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Naval Engineering

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Naval Engineering is the branch of engineering that focuses on the design, construction, maintenance, and operation of ships, submarines, and other marine vessels. It encompasses various disciplines, including hydrodynamics, structural analysis, propulsion systems, and marine systems, to ensure the safety, efficiency, and performance of maritime vehicles.
lightbulbAbout this topic
Naval Engineering is the branch of engineering that focuses on the design, construction, maintenance, and operation of ships, submarines, and other marine vessels. It encompasses various disciplines, including hydrodynamics, structural analysis, propulsion systems, and marine systems, to ensure the safety, efficiency, and performance of maritime vehicles.
ship construction (konstruksi kapal)
by wahyu naval
FIGURE 18.5 Construction of deep tanks
FIGURE 6.1 Typical aluminium alloy sections
Ship classification societies originally had varying specifications for steel: but in 1959, the major societies agreed to standardize their requirements in order to reduce the required grades of steel to a minimum. There are now five different qualities of steel employed in merchant ship construction and now often referred to as IACS steels. These are graded A, B, C, D and E, Grade A being an ordinary mild steel to Lloyds Register requirements and generally used in shipbuilding. Grade B is a better quality mild steel than Grade A and specified where thicker plates are required in the more critical regions, Grades C, D and E possess increasing notch-tough characteristics, Grade C being to American Bureau of Shipping requirements. Lloyds Register requirements for Grades A, B, D and E steels may be found in Chapter 3 of Lloyds Rules for the Manufacture, Testing and Certification of Materials.
FIGURE 7.1 Stress/strain relationship of shipbuilding materials
FIGURE 8.1 Vertical shear and longitudinal bending in still water
FIGURE 9.10 Metal cutting processes
FIGURE 10.1 Stress/strain relationship for parent/weld metals and butt/fillet weld detail
FIGURE 10.3 Backstep and wandering methods of welding
requisitioning information can be stored on the computer to be interfaced with the shipyards commercial systems for purchasing and material control. Sub-assembly, assembly and block drawings can be created in 2-dimensional and 3-dimensional form and a library of standard production sequences
FIGURE 14.1 Bulk carrier single shell side block unit
When any panel and the block assemblies are complete there will be some time buffer before their erection at the building berth, building dock or within the building hall to allow for any mishaps in the production schedule. Stowage is generally adjacent to the berth, dock or building hall and will vary in size according to the yard’s practice, some yards storing a large num- ber of units before transferring them to the berth or dock for erection in order to cut the berth/dock time to a minimum. Qanienrec af ereactinn far any narticnular chin vary fram chinvard tr chinvard
FIGURE 14.6 An erection sequence for a large double hull tanker
FIGURE 14.7 An erection sequence for a dry cargo bulk carrier
MECHANICAL LAUNCH TRIGGER (ELEVATION) FIGURE 15.3 Release arrangements for ship launch
FIGURE 16.4 Transversely framed double bottom construction
FIGURE 16.5 Longitudinally framed double bottom construction
FIGURE 16.6 Bulk carrier double bottom construction
the stern frame connection, at any shaft brackets, and in way of the hawse pipes where considerable chafing occurs. Further shell plate thickness increases may be found at the panting region, as discussed later in this chapter.
Figure 17.7 Bulk carrier — single side skin midship section
FIGURE 17.8 Bulk carrier — double side skin midship section
Stowing arm pedestal Closing arm pedestal
FIGURE 21.3 Stern frames
Construction in Tank Spaces
FIGURE 22.3 Longitudinal framing of oil tankers
FIGURE 22.4 12,700 tonnes Deadweight Oil Products/Chemical Tanker
5200 cu.m. SEMI-PRESSURIZED/FULLY REFRIGERATED LPG/NH, CARRIER
73 200 cu.m. FULLY REFRIGERATED LPG CARRIER
FIGURE 24.7 Cross-section of bulk carrier with side mounted 30 tonne wire luffing cranes
being affected by the lifting and lowering wire purchases which are led to hydraulic winches.
valve is fitted to a substantial box within the line of the shell plate containing the sea inlet opening (see Figure 26.2). This opening is to have rounded corners and be kept clear of the bilge strake if possible. The sea inlet box is to have the same thickness as the adjacent shell but is not to be less than 12.5 mm thick and need not exceed 25 mm. Sea inlets in tanker pumprooms within 40 per cent of the ships midship length are required to have compensa- tion generally in the form of a heavier insert plate in the shell. A grill may be fitted over the opening and a sacrificial anode will normally be fitted because the valve metal and steelbox set up a galvanic cell (see Chapter 27).
FIGURE 26.4 Diagrammatic arrangement of direct line cargo piping
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menghitung stabilitas kapal
by wahyu naval
Menghitung Stabilitas Kapal Kompetensi : Bangunan dan Stabilitas Kapal I -1 I. PENDAHULUAN A. Deskripsi Salah satu penyebab kecelakaan kapal di laut ,baik yang terjadi di laut lepas maupun ketika di pelabuhan, adalah peranan dari para... more
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Un mito da sfatare IL RADAR (italiano) NELLA 2^ GM UNA GUERRA TECNOLOGICA ED UN' OCCASIONE PERDUTA
by Gian Carlo Poddighe
Un tema trito e ritrito su cui si sono spesi inutilmente fiumi di inchiostro Nessuna difesa di inventori o primogeniture che non hanno alcun valore in una gestazione che è stata una scoperta collettiva e non può essere il vanto di un... more
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Design Principles of Ships and Marine Structures
by Bill Erick Castillo
S.C. Misra
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TEKNIK GALANGAN KAPAL
by Fauzi Imam HD
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La defensa de las Indias y del Mediterráneo, las Armadas Imperiales en el siglo XVI ( The Indies and Mediterranean defense, Imperial Spanish Armada in sixteenth century)
by Arturo Sanchez Sanz

2012, Historia Rei Militaris, Nº 2, pp. 6-17. ISSN 2254-7681

En el s. XVI mares y océanos se habían convertido en ajetreadas zonas de paso, confrontación, exploración, etc. por las que pululaban armadas, corsarios, piratas, comerciantes y aventureros tanto de coronas europeas como de reinos... more
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Reconstrução Virtual de uma Nau Quinhentista. FCT Report 2010
by Filipe Castro
Este projecto, teve como objectivo proceder à reconstrução de uma nau quinhentista, com base em informação arqueológica e documental, e analisar as suas características físicas e o seu desempenho. Com base nas fontes iconográficas,... more
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(2015). The Use of Copper and Lead Sheathing in Dutch East India Company Shipbuilding, International Journal of Nautical Archaeology
by Wendy van Duivenvoorde
Much has been written on the use of lead and copper sheathing in post mediaeval shipbuilding, yet evidence for such hull protection by Dutch shipwrights in the 17th and 18th centuries has received little attention. A discussion of the... more
Figure 1. Preserved section of Batavia’s sternpost with oak cover planking and pine sheathing boards. The well-preserved pine sheathing boards from the sternpost’s starboard side are displayed separately and thus not shown in this photograph. (Photograph: Wendy van Duivenvoorde)
Figure 2._Oak cover planking on port side of sternpost, Batavia shipwreck, BAT 6433 C-BAT 6439. (Illustration: Wendy van Duivenvoorde)
Figure 3. Oak cover planking on starboard side of sternpost, Batavia shipwreck, BAT 6246—-BAT 6251. (Illustration: Wendy van Duivenvoorde)
Figure 4. Fragments of copper sheathing and tacks from sternpost, Batavia shipwreck. (Photograph: Patrick Baker, with the permission of Western Australian Museum)
Figure 5. Fragments of copper sheathing protruding along the edge (left) from underneath the starboard pine sheathing of the sternpost, Batavia shipwreck. (Photograph: ABC Peach’s Australia, The Unlucky Voyage, 1990, with the permission of Western Australian Museum) It must be noted that the shipwreck Site G in Galle Harbour, Sri Lanka, yielded fragments of copper sheathing, found during an archaeological investigation
Figure 6. Copper tacks for fastening copper sheets to the sternpost, Batavia shipwreck. (Illustration: Wendy van Duivenvoorde)
Figure 8. Detail showing sheathing nail holes along edge of exterior of outer layer of copper sheet, Vergulde Draak ship’s sternpost, GT 3169 A. (Photograph: Patrick Baker, with the permission of Western Australian Museum)
Figure 9. Reconstruction of multiple layers of Vergulde Draak sternpost sheathing, GT 3169 A-C, GT 1442. (Illustration: Wendy van Duivenvoorde)
Figure 7. Exterior surfaces of copper sheets, possibly from Vergulde Draak’s sternpost sheathing, GT 92 A—D. (Illustration: Wendy van Duivenvoorde)
Figure 11. Copper sheathing in situ next to the hull timber to which it was originally attached, Site G, Galle, Sri Lanka. (Photograph: Patrick Baker, with the permission of Western Australian Museum (SL-A-10)) Figure 10. Fragment of copper sheathing, 92/GH/102, Site G, Galle, Sri Lanka. (Photograph: Patrick Baker, with the permission of Western Australian Museum (MA4464-41))
Figure 12. Detail of copper sheathing fragment stamped ‘NANTES’, 92/GH/102, Site G, Galle, Sri Lanka. (Photograph: Patrick Baker, with the permission of Western Australian Museum (SL-0-40))
Table 1. Copper and zinc content from copper-alloy sheet, Site G, Galle, Sri Lanka India ships (Van Duivenvoorde, 2012: 247-8). And while the use of double planking is better known on whaling ships, according to Cornelis de Jong (1972: 126; 1978: 19; 1979: 5, note 73; Zorgdragers, 1727: 330), the first historic references for reinforcing Dutch whalers with an additional layer of oak planking date only to 1660, coinciding with the beginning of Dutch fishing and whaling in the icy waters along the north and west coast of Spitsbergen (De Jong, 1978: 19). The Dutch joint-stock companies and VOC had been double-planking their ships since 1595 and 1602, respectively, (Van Duivenvoorde, 2015: 147-9, 186-7), more than half a century earlier. Moreover, De Jong makes no mention of historic accounts pertaining to the protection of stems, sternposts, or keels of Dutch whaling ships with either metal or wooden sheathing (1972: 126; 1978: 19; 1979: 5, note 73).
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ANSYS Parametric Design Language Guide (APDL)
by Zulham Mochtar
APDL stands for ANSYS Parametric Design Language
A scripting language that you can use to automate common task or even build your model in terms of parameter (variables).
The parameter NTEMP could be an array of temperatures at selected nodes; NTEMP(1) = -47.6 could be the temperature at node 27, NTEMP(2) = -5.2 could be the temperature at node 43, and so on. Similarly, EVOLUM could be an array of element volumes, and COMPSTRS could be an array of nodal component stresses, with each column representing a particular direction (X, Y, Z, XY, YZ, XZ, for example).
Figure 3.4: A Graphical Representation of a Table Array As shown in the above example, when configuring a table array you must set
Figure 3.5: An Example *VEDIT Dialog Box for an ARRAY
3.10.5.4. Filling an Array From a Data File Using *VREAD Figure 3.6: An Example *VEDIT Dialog Box for a TABLE You can fill an array from a data file using the *VREAD command (Utility Menu> Parameters> Array Parameters> Read from File). The command reads information from an ASCII data file and begins writing it into the array, starting with the index location that you specify. You can control the format of the inform- ation read from the file through data descriptors. The data descriptors must be enclosed in parenthesis and placed on the line following the *VREAD command. See Vector Operations (p. 35) for more information about data descriptors. The data descriptors control the number of fields to be read from each record, the width of the data fields, and the position of the decimal point in the field.
This same example, done via command input, would look like the following:
Figure 3.8: A Sample 2-D TABLE Array Dialog Box This same example, done via command input, would look like the following:
Figure 3.9: A Sample 3-D TABLE Array Dialog Box
Figure 3.10: Time-History Forcing Function
In the following example, the result array is first dimensioned (Z1). The *VOPER command then adds columr 2 of X to column 1 of Y, both starting at row 1, and then places the result into Z1. Notice that the starting location (the row and column index numbers) must be specified for all array parameters. The operation ther progresses sequentially down the specified vector. The examples below illustrate the use of some of these commands. Refer to the Command Reference for syntactical information about these commands. For all of the following examples, the array parameters (of type ARRAY) X, Y, and THETA have been dimensioned and defined.
Figure 3.11: Sample Plot Using *VPLOT, ,arrayval(1,1) ,2 Figure 3.12: Sample Plot Using *VPLOT, , tableval (1,1) , 2 The following are example *VPLOT commands and their resulting plots. Note that since ARRAY data is un ordered it is plotted as a histogram; TABLE data is ordered and is therefore plotted as a curve.
Figure 3.14: Sample Plot Using *VPLOT, tableval(1,0),tableval(1,1) ,2 Figure 3.13: Sample Plot Using *VPLOT , table2(1),tableval(1,1) ,2
3.10.9. Modifying Curve Labels When you use *VPLOT to create your curves, default labels are assigned. Normally, the label for curve 1 is “COL 17 the label for curve 2 is “COL 2” and so on; the column number is the field containing the dependent variables for that particular curve. You can use the /GCOLUMN command to apply your own labels to the curves (any string of up to eight characters).
Figure 3.15: Sample Plot With User-specified Labels
As with the *CREATE command, parameters are not evaluated but are written verbatim into the macro file. Note that you do not make the last line a *END command.
4.1.5. Using Macro Library Files As a convenience, ANSYS allows you to place a set of macros in a single file, called a macro library file. You can create these either through the *CREATE command or through a text editor. Given that macro librarie tend to be longer than single macros, using a text editor normally provides the best approach.
4.6. Using the STATUS and _RETURN Parameters in Macros
*ask,parml, ‘username (enclose the username in single quotes) |
Figure 5.2: A Typical Multiple-Prompt Dialog Box
The following is a complete list of APDL operators:
In ANSYS, you define a TABLE parameter "Ttx" using the *DIM command (Utility Menu> Parameters> Arra Parameters> Define/Edit). Specify 4 rows, 5 columns, 1 plane, row label of TIME, and column label of X- COORD. Note that the data table you created has four rows and five columns of data, plus the row and column index values. Then read in the file as described earlier, specifying 2 skipped lines. The TABLE array in ANSYS would look like this: For this example, create (in a spreadsheet application, a text editor, etc.) a 2-D table named "T2data" con- taining temperature data as a function of time and x-coordinate and read it into a TABLE array parameter called "Ttx." The table, in its ASCII form, would look like this:
In ANSYS, you define a TABLE parameter "Ttxy" using the *DIM command (Utility Menu> Parameters> Array Parameters> Define/Edit). In the case of a 3-D table, the table is dimensioned according to the number of rows, columns, and planes of data. The first column (TIME) is the row index values and the first row is the column index values. Specify 4 rows, 5 columns, 2 planes, row label of TIME, column label of X- COORD, and plane label of Y-COORD. Note that the data table you created has four rows and five columns
The following table lists the various specification commands and the vector and matrix array commands that they affect. In the following, the results array (CMPR) is dimensioned. The two *VFUN commands, in conjunction with the preceding *VMASK and *VLEN commands, then compress selected data and write them to specified locations in CMPR. The complement to the COMP operation is the EXPA operation on the *VFUN command.
Table 4.1 _RETURN Values
Additional *get commands for a new entity=PRODUCT
Check for Ansys gateway commands/feature RPR4
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La protección de las costas en el Mundo Micénico, el caso de Pilo (Coast defense in mycenaean world, the case of Pylos)
by Arturo Sanchez Sanz

2014, Revista de Historia Militar 1, pp. 1-15. ISSN: 2254-3619

For the reconstruction of the military Mycenaean world scarcely we possess the information extracted from diverse slats written in Linear B, as well as the remains of some pictorial representations and scanty archaeological remains... more
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Ship Construction
by wahyu naval
FIGURE 2.1 Principal ship dimensions
FIGURE 3.4 Bulk carriers
FIGURE 3.5 Oil tankers
FIGURE 5.1 Steel sections of shipbuilding
FIGURE 6.1 Typical aluminium alloy sections
Since stress is directly proportional to strain, the stress is equal to a constant which is in fact the slope of the straight line part of the graph, and is given by:
FIGURE 7.2 Charpy impact test
FIGURE 8.1 Vertical shear and longitudinal bending in still water
WELDING CIRCUIT
FIGURE 9.6 Metal inert gas welding
TUNGSTEN INERT GAS (TIG) PROCESS
FIGURE 9.7 Electro-gas and Electro-slag welding
FIGURE 9.8 Friction welding heated to a given temperature, and a confined stream of oxygen is then blown onto this area. The iron is then oxidized in a narrow band, and the molten oxide and metal are removed by the kinetic energy of the oxygen stream. A narrow parallel sided gap is then left between the cut edges. Throughout the cutting operation the preheat flame is left on to heat the top of the cut since most of the heat produced by the reaction at the cutting front is not instantaneous, and tends to be liberated at the lower level of the cut only. Alloying elements in small amounts are dissolved in the slag and removed when cutting steel. However, if they are present in large quantities, alloying elements, especially chromium, will retard and even prevent cut- ting. The reason for this is that they either decrease the fluidity of the slag
FIGURE 10.1 Typical mild steel stress/strain relationship of parent and weld metal
FIGURE 10.2 Plate edge preparations
FIGURE 10.6 Inspection of welds
FIGURE 11.1 Shipbuilding process
FIGURE 13.1 Numerical flame cutting control system
PLATE ROLLS’ Heavy duty bending rolls used for rolling shell plates, etc., to the correct curvature are hydraulically operated. Two lower rolls are provided and are made to revolve in the same direction so that the plate is fed between them and a slightly larger diameter top roll which runs idly (see Figure 13.3). Either or both ends of the top roll may be adjusted for height, and the two lower rolls have adjustable centres. With modern bending rolls, plates up to 45 mm thick may be handled and it is possible to roll plates to a half circle. These large rolls are also supplied with accessories to allow them to undertake heavy flanging work with the pressure exerted by the upper beam, for example, ‘troughing’ corrugated bulkhead sections.
3-dimensional steel units to form the ship structure into which the outfit and equipment was fitted at the berth and after launching at the fitting out quay. Piping systems, ventilation and the machinery units were fitted into the erected hull as independent items. Likewise the accommodation spaces were lined out and fitted with the furniture and other fittings in situ. Whilst the production methods applied to the steelwork fabrication and erection were time saving and cost-effective the haphazard and largely uncontrolled methods of outfitting detracted from the overall production engineering of the ship. Rather than plan outfit installation on a total ship system basis it is today common practice to plan this work for zone installation, the zone corresponding to a main compartment area which may be broken down into blocks or smaller assemblies. Pre-outfitting of each assembly or block may
FIGURE 14.4 Cabin/toilet module
FIGURE 14.5 An erection sequence for a general cargo ship
FIGURE 14.6 An erection sequence for a bulk oil tanker
FIGURE 14.7 An erection sequence for a dry cargo bulk carrier
FIGURE 14.8 Typical block erection
MECHANICAL LAUNCH TRIGGER (ELEVATION) FIGURE 15.3 Release arrangements for ship launch
FIGURE 16.4 Transversely framed double bottom construction
FIGURE 17.2 Side shell with transverse framing
FIGURE 17.3 Web frame and tank side bracket
FIGURE 17.4 Panting arrangements forward
FIGURE 18.1 Plain watertight bulkhead
FIGURE 18.4 Construction of deep tanks
FIGURE 18.5 Shaft tunnels
FIGURE 18.7 Small solid pillars
FIGURE 19.4 Hatch openings
FIGURE 19.7 Portable hatch covers and bulwarks
FIGURE 21.3 Stern frames
FIGURE 21.6 Sterntubes
FIGURE 21.7 Bossings and ‘A’ brackets
FIGURE 22.1 Midship section of coastal tanker with trunk
Bottom plating 20mm thickness amidships Drain holes Keel plate 1250mm x 27mm thick Bottom longitudinals 425mm x 14.5mm O.B.P.
FIGURE 22.4 Longitudinal framing of oil tankers
FIGURE 22.6 Longitudinally framed oil tanker
Longitudinal bulkheads which are oiltight may be conventionally stiffened 1 may be corrugated with the corrugations running horizontally. Vertical orrugated centre line bulkheads may be fitted. Conventional stiffening is rranged vertically where the side framing is vertical, and arranged longit- dinally when the side is longitudinally framed. Vertical webs are fitted to he longitudinal bulkhead when this is corrugated or longitudinally framed. ‘orrugated longitudinal bulkheads are only permitted in ships of less than 00 m in length.
5200 cu.m. SEMI-PRESSURIZED/FULLY REFRIGERATED LPG/NH, CARRIER
4000 cu.m. FULLY PRESSURIZED LPG CARRIER
73 200 cu.m. FULLY REFRIGERATED LPG CARRIER
FIGURE 24.1 Stiffening in way of mast and heavy derrick
FIGURE 24.2 Derrick rigs
when the door is opened. Combined side door/hatch covers are fitted in designs where the ship is low in the water relative to the height of quay in order to provide sufficient head room for forklift truck operation (see Figure 25.4). With the side port elevator system referred to above a combined door/hatch is fitted to the hatch carrying part of the tower which houses the upper part of the cargo elevator.
FIGURE 26.1 Bilge piping arrangement
the sea inlet opening (see Figure 26.2). This opening is to have rounded corners and be kept clear of the bilge strake if possible. The sea inlet box is (0 have the same thickness as the adjacent shell but is not to be less than 12.5 mm thick and need not exceed 25 mm. Sea inlets in tanker pumprooms within 40 per cent of the ships midship length are required to have compensa- ‘ion generally in the form of a heavier insert plate in the shell. A grill may se fitted over the opening and a sacrificial anode will normally be fitted ecause the valve metal and steelbox set up a galvanic cell (see Chapter 27).
FIGURE 27.2 Aluminium to steel connections
FIGURE 28.2 Midship section of refrigerated cargo ship
FIGURE 28.3 Insulation details
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Clasificacion y tipos de buques
by Francisco López
Ing. Naval
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Mind the stratigraphic gap: Roman dredging in ancient Mediterranean harbours
by Christophe Morhange

2010

"It is generally speculated that primitive harbour dredging began during the Bronze Age along the Nile, Euphrates, Tigris and Indus rivers1. For the Roman period, Vitruvius gives a few brief accounts of dredging, although direct... more
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Le criticità ed i condizionamenti nello sviluppo della Regia Marina negli anni '30. Gian Carlo Poddighe
by Gian Carlo Poddighe
Una rivisitazione della situazione degli Apparati Motore a vapore della Regia Marina Italiana, in relazione alle deficienze ed alle cause, nel contesto dell' industria e della cantieristica italiana degli anni 30 del secolo scorso. La... more
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NCVS 2014
by arif sakato
Rules about Marine Vessel by Ministry of Transportation
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Pengelasan (Welding) dalam Pembangunan Kapal Baja
by Reva Permadi
Proses pembangunan kapal merupakan suatu aktivitas yang dilakukan mulai dari perencanaan kapal (desain) sampai dengan penyerahan produk kapal kepada pemilik kapal. Pembangunan kapal ini dilakukan melalui suatu tahapan proses yang salah... more
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general arrangement
by wahyu naval
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Prinsip Kerja Pompa dan Kompresor
by Ilyas Ramadhan
Pompa : Mesin fluida yang digunakan untuk memindahkan fluida dari satu tempat ke tempat lain. Dalam menjalankan fungsinya tersebut, pompa mengubah energi gerak poros untuk menggerakkan sudu-sudu menjadi energi tekanan pada fluida.... more
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Multi-objective Hydrodynamic Optimization of the DTMB 5415 for Resistance and Seakeeping
by Andrea Serani and 
4 more
Matteo Diez
Omer Goren
Gregory Grigoropoulos
Michel Visonneau

2015, FAST 2015 - 13th International Conference on Fast Sea Transportation, Washington DC, USA

The paper presents recent research conducted within the NATO RTO Task Group AVT-204 “Assess the Ability to Optimize Hull Forms of Sea Vehicles for Best Performance in a Sea Environment.” The objective is the improvement of the... more
Abstract: The paper presents recent research conducted within the NATO RTO Task Group AVT-204 “Assess the Ability to Optimize Hull Forms of Sea Vehicles for Best Performance in a Sea Environment.” The objective is the improvement of the hydrodynamic performances (resistance/powering requirements, seakeeping, etc.) of naval vessels, by integration of computational methods used to generate, evaluate, and optimize hull-form variants. Several optimization approaches are brought together and compared. A multi- objective optimization of the DTMB 5415 (specifically the MARIN variant 5415M) is used as a test case and results obtained so far using low-fidelity solvers show an average improvement for resistance and seakeeping performances of nearly 10 and 9%, respectively.
Figure 1. INSEAN - Computational panel grid (G1)
Figure 2. INSEAN/UI - Panel-grid convergence analysis (WARP)
are very small and grid G1 is deemed adequate for current studies. Figures 3a, 3b, and 3c show a comparison with EFD data from INSEAN (Olivieri et al, 2001), revealing a reasonable agreement especially for low speeds. Seakeeping results are presented in Figs. 3d and 3e in terms of heave and pitch response amplitude operators (RAOs) at Fr=0.41 and head wave. The trend is compared to UI data (Longo and Stern, 2005), showing a reasonable agreement at least for peak values and peak frequencies. Table 2 summarizes the main results for the original hull. Design Space Definition and Sensitivity Analysis. Four orthogonal basis functions and associated design variables are used for the hull, whereas two functions/variables are used for the sonar dome, as summarized in Table 3. Three design spaces are assessed:
Table 3. INSEAN/UI - Orthogonal functions parameters, for shape modification Table 4. INSEAN/UI - Multi-objective deterministic particle swarm optimization results A preliminary sensitivity analysis is performed, for calm water at Fr=0.25 (18 kn) and Fr=0.41 (30 kn), and for the seakeeping merit The design space C.1 has produced the most promising design, with an improvement of nearly 6.7% and 6.8% for F1 and F2, respectively. It may be noted that the design spaces C.2 and B.2 provide an average reduction of the objective functions F1 and F2 larger than C.1 (Table 4). Nevertheless, C.2 design also gives
Figure 5. INSEAN/UI - Pareto fronts for design space C.1 and C2 Figure 6. INSEAN/UI - Selected optimal shape for design space Cl Figure 7. INSEAN/UI - RAOs of heave (a) and pitch (b) at Fr=0.41 in head wave, and roll (c) at Fr=0.25 in 30 deg stern wav
Figure 8. INSEAN/UI - Wave elevation pattern and pressure field of the selected optimal hull for design space C.1, compared with the original
Figure 10. ITU - A graphical representation of static ANN during recall period
Figure 9. ITU - Design variables (control points) on the hull Table 7. ITU - Computed viscous resistance components of the original hull form scaled model (LBP = 20 m)
Figure 12. ITU - Predicted and measured (circles) heave RAOs in head seas (180 deg)
Figure 11. ITU - Panel distribution over the hull and its free- surface vicinity
Figure 13. ITU - Regression performance of the ANN training
Figure 15. ITU - Comparison of the cross sections of the initial and the optimal hull forms BACT RTE UP EUMIECUEUUEE CTEM SCECRLEUEE UT EMER UPLEUMIEEGE UM FEM Ele LIAO on 250 variant hull forms and their performances in resistance and seakeeping and on a trained ANN over the sample space, a SQP
Figure 14. ITU - Experimental area (sample space) and Pareto frontier determined by means of ANN and SQP where w = 0,0.1,...,0.9, 1.0 is employed as a weighting factor. The selected optimization algorithm is based on sequential quadratic programming (SQP) within Matlab optimization toolbox, since it is very suitable for constraint optimization problems whose design variables include upper and lower bounds. Schittkowski (1985) showed the success of this algorithm in many aspects such as accuracy, efficiency and
Figure 17. ITU - Contour plot of the wave patterns of the initial and the optimal hull forms (30 kn) Figure 16. ITU - Wave deformations of the initial and the optimal Fig hull at 18 and 30 kn and
process is carried out to optimize the prescribed aggregate objective function with weighting factors w. The optimal forms for each weighting factor (wW) are investigated by considering Fe mbinea in the ANN training process (see Table 8). The SQP application on the metamodel provided by ANN gives an optimal point, which is expected to be part of the overall Pareto front. An optimal point is selected on the Pareto front according to the changes in the Pareto curve, in order to give favorable results for both F1 and F2. Figure 14 shows F1 vs F2 values of the variant hull forms, the approximated Pareto front and the optimal design. The comparison of the cross sections of the initial and the optimal hull forms can be observed in Fig. 15. Wave deformations of the initial and the optimal hull forms, for 18 and 30 kn, are presented in Fig. 16, which points out the success of the selected optimal hull. The contour plot of the wave patterns of the initial and the optimal hull forms can be compared in Fig. 17. The summary of the seakeeping performance of the present multi-objective Figure 18. NTUA - Spline sheet on the computational grid
Figure 19. NTUA - Hull variants of the multi-objective optimization (a), and body plans of the (red) optimized hull compared to the (black) parent hull (b) SWAN2 2002. The Ship Wave ANalysis is a software package for the hydrodynamics analysis developed at MIT (Kring and Sclavounos, 1995). SWAN2 2002 distributes quadrilateral panels over the ship hull and the free surface to derive numerically the steady and unsteady free-surface potential flow around ships, using a three-dimensional Rankine Panel Method in the time domain. Only the calm water results are used in the present study. A batch file is used to integrate SWAN2 with the CAESES/FFW. Additional calculations in calm water have been carried out via a potential flow code developed in-house at Laboratory for Ship and Marine Hydrodynamics (LSMH) of NTUA (Tzabiras, 2008). The code solves the non-linear potential flow around the ship, by calculating iteratively the free surface, while both the dynamic and kinematic conditions are satisfied on it. The free surface and the solid boundary are covered by quadrilateral elements. The distribution of panels varies, being denser near geometrical discontinuities and areas of expected high pressures. The Laplace equation is solved according to the classical Hess and Smith (1968) method. An iterative Lagrangian procedure is adopted to cope with the non-linear problem, in conjunction with an Eulerian solution of the vertical momentum equation. Table 12 has been derived on the basis of this method. Within CAESES/FFW, the geometry of the hull form is represented by a set of basic curves, providing topological information (design waterline, centerline, deck-line) and a set of 19 section curves. All of them are either F-splines, or B-splines. The hull surface is generated by interpolating the parametric- modelled section curves. The parent hull is split into three regions: the main hull, the sonar dome and the skeg, assigning specific design variables for each of them. A total number of ten design variables is employed, five of which are used to define the sonar dome. Table 11 includes the upper and lower values of the design variables.
Figure 21. NTUA - Wave deformations of the parent and optimized hull at 18 kn
Figure 20. NTUA - Comparison of the wave elevation generated by the initial and the optimized geometry for the Fr=0.25
Figure 23. INSEAN/UI - Effects of the low-fidelity solver on the optimization outcomes: preliminary sensitivity analysis for total resistance improvement in calm water ECN/CNRS has verified the optimized geometry by INSEAN/UI (Fig. 6). At the current stage, the verification includes only calm water performance of the original and optimized C.1 geometries, in full scale, and at moderate and high Froude numbers (Fr=0.25 and 0.41). The hull performances are computed in a free to sink and trim condition by combining the free-surface and moving mesh capabilities with a rigid body motion solver for the flow/motion interaction. Table 14 summarizes the normalized computed forces and motions to reach the final equilibrium state. Concerning the EFD data for the original geometry in model scale (from IIHR; Longo and Stern, 2005), only the trim angle and the sink can be compared with the CFD values, under the hypothesis that the scale effect is weak on these quantities. EFD predicts a trim angle of 0.085 deg at Fr=0.25 and -0.421 deg at Fr=0.41 and the measured sink value is 0.189 at Fr=0.25 and 0.619 at Fr=0.41. Under the aforementioned hypothesis, this is in agreement with the CFD values from Table 14. It may be noted that the computed trim is close to the experiments for both RANSE and potential flow; for the computed sinkage, the agreement appears correct with RANSE, whereas it is under predicted at both speeds with the potential flow (see Table 3).
Table 1. DTMB 5415 main particulars (full scale)
Table 2. INSEAN/UI - Potential flow solver solution for the original hull Multi-objective Hydrodynamic Optimization of the DTMB 5415 for Resistance and Seakeeping
Figure 4. INSEAN/UI - Sensitivity analysis of the design variables
Table 6. INSEAN/UI - Summary results for selected designs (F2)
Table 8. ITU - First 10 hull variants in terms of the regression coefficients for each control point on the hull (from the database used in ANN training process)
Table 9. ITU - Comparative seakeeping performances
SPP-86. The seakeeping qualities of the parent and the variant hull forms are calculated by the SPP-86 code, developed at LSMH of NTUA to implement the Salvensen, Tuck and Faltinsen (1970) strip theory. The code distributes Kelvin sources along the wetted part of each ship section following Frank (1967) method. The estimated dynamic responses encompasses vertical and lateral motions, velocities and accelerations and velocities at specific points for a variety of wave frequencies and heading angles.
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Steve Murdoch, ‘Surfing the Waves : Scottish Admirals in Russia in their Baltic Context’ in Journal of Irish and Scottish Studies, 3, 2 (2010), pp.59-86.
by Steve Murdoch
This article explores the migration of Scottish mariners into foreign service in the 17th and 18th centuries. It challenges any notion of 'special relationship' between Scotland and a particular maritime nation (as is often claimed) by... more
Appendix IV: Scottish Shipbuilders in Scandinavia and Poland-Lithuani 1580-1650
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Performance analysis of ducted marine propellers. Part II - Accelerating duct
by Rodolfo Bontempo and 
1 more
Marcello Manna

2018, Applied Ocean Research

This paper completes the work presented in the companion paper [Bontempo et al., Appl. Ocean Res., 58 (2016) 322 - 330] by presenting the investigation of the flow around a propeller ducted with a so-called accelerating duct. To this aim,... more
Fig. 7: Effect of the chord variation onto the performance coefficients.
Fig. 8: Duct geometries characterised by the best ideal propulsive efficiency for Crp = 2 and Cr = 4. efficiency can be computed as
Fig. 6: Effect of the maximum camber variation onto the performance coefficients.
respectively. In the above equations, Cr is the thrust coefficient defined as Cr = T/($pU2,Arot), where T is the overall thrust, U. is the free stream velocity, p is the fluid density, and A,.; is the rotor swept area. Note that, the contribution to the overall thrust T has to be split between the rotor (To¢) and duct (Tuuce) thrust, so that Cr = Cryrot + Crduct- Finally, the quantity Tduct; appearing in the above equations, is defined as Tauct = Crauct/Cr. By convention Cr duct as well as Tduct are considered to be positive if the axial pressure force exerted by the fluid on the duct is concordant to the rotor thrust and vice versa. Having said that, from equation (1) it can be easily shown that if the duct axial force is concordant to the rotor thrust, i.e., Crduct > 0 and Tauct > 0, then the axial velocity at the disk for the ducted configuration is greater than the one of an open propeller (C'r,duct = Tduct = 0) with the same Cr value. For this reason, a duct which experiences a pos- itive thrust is also named “accelerating duct”. In this case it is easy to prove from equation (2) that a propeller enclosed in an accelerating duct is characterised by an higher 7;q value in comparison with an open propeller with the same Cr. Finally, inspecting equations (1) and (2), it can be readily understood that both w, and nia are monotonically increasing function of Tg,,-¢ as well as of Cr.auct (see also Figures 2 and 4 of the companion paper [2]). As stated in Section 1, the so-called accelerating duct of- ers the possibility of increasing the propulsive efficiency in comparison with an open propeller characterised by the same overall thrust coefficient. In the companion paper [2], the flow around a ducted propeller has been qualitatively investigated by means of the axial momen- tum theory [3, 4, 52] which, assuming the flow to be steady, inviscid, incompressible and axisymmetric, mod- els the rotor with an actuator disk introducing a uniform jump in the static pressure across it without any change in the axial and radial velocity. Further assuming that the tangential velocity is zero everywhere and neglect- ing the effects of the wake convergence [43-46], the axial momentum theory returned that the area-averaged di- mensionless axial velocity at the disk U, and the ideal propulsive efficiency read [2]
Although the axial momentum theory can give some insights on the operating principles of ducted propellers, it cannot evaluate the thrust exerted on the duct for a prescribed geometry and for a given overall thrust coef- ficient. Moreover, it should be recalled that equations 1) and (2) are valid only for a uniformly loaded disk [2]. Finally, the axial momentum theory disregards all non- inear contributions associated to the wake contraction and rotation. For these reasons, both in Part I and II of this work the nonlinear and semi-analytical actuator disk theory of [6] is employed. In this approach the axisym- metric, inviscid, steady and incompressible flow through a ducted actuator disk is modelled as a superposition of ring vortices arranged in the rotor wake and along the duct surface. The method strongly couples the flow in- duced by the duct and the rotor, and takes into account the slipstream contraction and rotation, and the radial variation of the rotor load. Moreover, contrarily to the axial momentum theory, it can evaluate the duct thrust for a given rotor load and duct geometry. To give an example, both equation (2) and the semi-analytical ac- tuator disk method are used to evaluate the variation of the maximum value of 7;q with the overall thrust coeffi- cient for a NACA 5415 duct section (see Figure 1). The latter is characterised by a unity ratio between the chord and the actuator disk radius ogg, and by an incidence (angle between the chord line and the rotor axis) equal to 12.5°. As in Part I, for this and for all successive sim- ulations reported in the paper, the advance coefficient is set equal to 0.5 and the propeller load is modelled as a second order polynomial of the Stokes stream function. Moreover, since equation (2) requires the knowledge of Tduct (@ quantity that cannot be evaluated by means of the momentum theory) the duct thrust computed by the semi-analytical method is employed. Inspecting Figure 1 it can be observed that a large difference appears between
mass flow swallowed by the rotor m, and ideal propulsive efficiency nia) for a given duct geometry and for each prescribed value of the overall thrust coefficient Cy. Al- though the analysis will be carried out for 0 < Cr < 10. only those operating conditions characterised by a maxi- mum value of the canonical pressure coefficient less than the Loftin’s critical value 0.8 will be considered. To give an example, the aforementioned semi-analytical actua- tor disk method is used to evaluate the variation of the maximum value of Cc with the overall thrust coefficient or a NACA 5415 duct section (see Figure 1). Inspect- ing Figure 2, it can be observed that max(C) is greater than the critical value 0.8 both for low and high values of Cr. For low values of the overall thrust coefficient Cr, the mass flow swallowed by the rotor is small (see equa- tion (1)), and, consequently, the front stagnation point is placed on the duct inner surface. Hence, a high veloc- ity peak exists on the duct external surface in the leading edge region as a consequence of the large curvature of the near wall streamline. Therefore, in these circumstances, a high pressure recovery must take place along the ex- ternal surface. This could result in a Cy, value greater than 0.8 leading to a separation zone (represented as a grey area in Figure 2) along the duct external surface. Conversely, for high Cr values the front stagnation point is typically located on the upper surface and the Ch has a maximum on the inner surface.
‘ig. 4: Maximum value of the canonical pressure coefficient. D_ left; D, right
Fig. 5: Effect of the maximum thickness variation onto the performance coefficients.
Fig. 9: Mean effects on the ideal propulsive efficiency of the main factors and first-order interactions. Top: Cp = 2. bottom: Crp = 4.
Fig. 11: Plots of factor effects for the SN ratio.
Tab. 1: Factor levels for the one-factor-at-a-time analysis. Tab. 2: List of the investigated duct cross section profiles.
Tab. 3: Effects of varying one factor at a time (Crp = 2; D_,) Tab. 4: Effects of varying one factor at a time (Cr = 4; D41).
with ApBoCo. However, this could be a wrong conclu- sion since all it can inferred about the optimum level of A, for example, is that A. is optimal when B and C are set to level 0 (if B and C are not fixed at BoCo, then A+; could not be the optimum level) and that a 1.65% increase in 7;q is obtained moving from Ag to Ay; with Bo and Cp fixed. Another drawback of the one-factor-at- a-time analysis is that the interactions existing between two or more factors cannot be evaluated. In particular, tor at a time, while keeping all other factors fixed. Al- though this kind of approach was very useful to verify some of the axial momentum theory outcomes and to obtain interesting insights on the effect of the design fac- tors variations, a few shortcomings exist. For example, inspecting the results of Table 4 it could be inferred that, in this one-factor-at-a-time analysis, the optimal levels of A, Band C are Ai;B,,C_, which should correspond to a 1.65 + 2.25 + 0.56 = 4.46% increase in nq in comparison
Tab. 7: Cross product array (Cr = 4). Pareto principle, namely the Pareto ANOVA method (see Park [54] for details) whose results are reported in Tables 8 and 9 for the case Cr = 2 and Cr = 4, respectively Figure 9 represents the factor effects for both cases Cr = 2 and Cr = 4. Only the main effects (the effect of a single factor) and those of the second order interactions are reported in the figure since the effects of the higher order interactions are extremely small. The data show that, for each value of Cy, a beneficial effect on 7;g can be obtained by increasing the thickness and camber, and by decreasing the incidence. Contrariwise, the main effect of the chord is positive or negative depending on the value of Cr. However, as previously pointed out, the optimum level of C is always C1, for both Cp = 2 and Cr = 4. This discrepancy is obviously due to the presence of three important interactions, namely AC, BC and CD, which significantly affect the value of the response variable 14, especially for Cr = 4.
Tab. 5: Factor levels for the orthogonal array analysis. Tab. 6: Cross product array (Cp = 2).
Tab. 9: Pareto ANOVA table (Cr = 4.)
the last row shows the percentage contribution ratio de- fined as the ratio between the square of the difference (row 4) and the sum of all elements reported in row 4. This contribution ratio is obviously a measurement of the factor significance in comparison with all other factors or interactions. scending order. It can be concluded that, in the inves- tigated design space, factors B, A and D are the most significant. However, the chord and the interactions AC, BC and CD are also significant, a fact that is verified by applying a classical ANOVA approach whose results are not reported here for the sake of brevity.
Tab. 10: Pareto ANOVA table for the SN ratio (Cr = 2) Tab. 11: Pareto ANOVA table for the SN ratio (Cr = 4
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Guerra per la Sicilia e guerra della Sicilia. Il ruolo delle città siciliane nel primo conflitto romano-punico
by Claudio Vacanti

2012

In Sicily, at the beginning of the First Punic War, Rome was able to rely on the sole support of Messana. Yet, only one year later, and without any decisive Roman victory, the cities of Eastern Sicily and Segesta, followed by the King of... more
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Master's Thesis: Foil Control Design for Hydrofoil Craft
by Enzo Lazo
A hydrofoil craft is known for the ability to lift its hull out of the water, increasing the hydrodynamic efficiency of the boat. This work details the experimental process of developing a computational control system for the foils of a... more
Table 4.8: PID Control Parameters Figures 4.38 to 4.40 show the unit step response for each of these con-
be obtained with smaller control gains for the estimated transfer function.
For K, = 34.68, Kk; = 4.25.
For K, = 45.82, K; = 41.07, Ka = 0.95.
4.44 to 4.46.
State-space controller
Table 2.1: 6 DOF standard motion notation used for marine vehicles. (SNAME, 1950) To determine the equations of motion, two reference frames are considered:
Raspberry Pi logging pseudo-algorithm
Table 4.2: Foil Angle Calibration
Table 4.3: Foil Angle Calibration Statistics table lists some useful statistics: Both MSE and standard deviation values are sufficiently small. Maximum
Arduino’s pseudo-algorithm for filter analysis experiment are listed below.
Table 4.4: Filter Statistics
Table 4.5: Preliminar datasets
Table 4.7: Second-Order Estimated Models
outcome of this experiment.
Figure 4.29: Comparison between actual and simulated response
Table 4.6: First-Order Estimated Models
trollers. Figure 4.38: Step response for P controlled plant
Figure 4.32: Comparison between actual and simulated response
Figure 4.33: Comparison between actual and simulated response
signal u(t) from dataset DO5 on the computed transfer function. PID Control Law for Estimated Transfer Function
Figure 1.2: Hydrofoil Configurations: surface piercing and fully submerged. (IHS, 1998) piercing and fully submerged, as shown in Figure 1.2.
Let the position-orientation vector 7 with respect to the earth-fixed frame be defined and the linear-angular velocity vector 1 with respect to the body-fixed frame be
dynamics of a marine vehicle can be derived (Fossen, 1994): matrix and 7 is a generalized vector of forces and moments, defined as which can be be linearly superposed by different components, based on the gen-
adding a reference precompensator NV, as shown in Figure 2.4.
shown on Figure 3.1. Some definitions are made about the parts of Figure 3.1, as follows: 3.1. General System
equires cooling fan for temperature contro
present work.
for experimental tests is shown in Figure 3.6. Figure 3.6: Computer Architecture for Experimental Tests
for physical connection. The variable to be controled is hydrofoil angle, shown in drofoil system, which consisted of hydrofoil, linear actuator, and mechanical parts
The second part consisted in identifying the black-box transfer function. An
Thus a driver motor is usually required. Figure 4.3 shows how it works.
Table 4.1: Driver-actuator characterization Since there is a non-linearity (range) resulting in zero speed to the linear
to a value of zero (See Figure 4.4).
part that the Foil Angle potentiometer was mounted on (See Figure 4.11).
Figure 4.18: Responsiveness of 10 and 20 Hz one pole low-pass filters
Figure 4.21: Noise rejection for 10 and 20 Hz one pole low-pass filters
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Arquitecturas flotantes
by FUNDACIÓN JUANELO TURRIANO
Entre la segunda mitad del siglo XIX y las primeras décadas del XX, razones técnicas, económicas y sociales impulsaron la aparición y la conquista del mar por un tipo de barco desconocido hasta entonces, el gran barco de pasajeros.... more
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Bellum Piraticum. La Armada romana que conquistó el Mediterráneo (Bellum Piraticum. The Roman Navy that Conquered the Mediterranean)
by Arturo Sanchez Sanz

2024, Historia de la Guerra Especiales, 7, pp. 11-18. ISSN 2530-0377

An 1 refiere 30 hombres que se traen de cinco lugares y están «yéndose como remeros a Pleurón». PUERTO PRINCIPAL -Voldhokiliá. MAS DE 150 KM DE COSTA -SOBRE TODO ZONAS ROCOSAS SISTEMA DE VIGILANCIA DE LA COSTA (An 657, An 654, An 519, An... more
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Full-scale Fluid-structure Interaction Simulation and Experimental Validation of High-speed Planing-hull Slamming with Composite Panels
by Matteo Diez and 
1 more
Dong-Hwan Kim

2016, 31st Symposium on Naval Hydrodynamics

The current work presents a partitioned tightly coupled fluid-structure interaction (FSI) simulation of composite panel slamming for a high-speed planing hull including validation with full-scale experiments. The prediction capability of... more
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Optimizing Trimaran Yacht Hull Configuration Based on Resistance and Seakeeping Criteria
by Bagiyo Suwasono and 
4 more
Prabhawatya Poundra
Didik Hardianto, Ir., MT
I Ketut Aria Pria Utama
I. Ketut
An investigation into the optimization of a trimaran yacht, which is equipped with axebow, was carried out numerically. The study was focused on the analysis of resistance and seakeeping which can provide the best performance to the... more
In order to satisfy the needs of a comfortable vessel and help tourist in marine-tourism transportation sector, a design model of trimaran based on resistance and seakeeping criteria is developed. The principal particulars and body plan of model are shown in Figs.1 and 2 and Tables 1 and 2. Separation between hull is made fixed on the length of main-hull and the S/L is 0.078. Table 1. Trimaran Vessel A,B and C Principle Particulars
Table.3 Trimaran A,B and C Total Resistance Seakeeping Analysis
The resistance analysis was carried out by using Computational Fluids Dynamics (CFD) software. CFD is « branch of fluids mechanics that uses numerical analysis and algorithms to solve and analyze problems that involv: fluids flow, and computers are used to perform the calculations which were required to simulate the interaction o liquids and gases with surfaces defined boundary conditions [5]. In all of these approaches, the same basic procedure is followed.
Table.2 Trimaran A,B, and C CFD Results
Table 5. Trimaran Vessels RMS (180°) Table.7. Trimaran Vessel RMS (0°) From the simulation that had been done, the results from each wave’s directions can be shown in the table.5, 6 and 7. For the Added resistance from each models, will be attached as additional data. tables for each wave coming directions to the ships.
Table 6. Trimaran Vessels RMS (90°)
Table.8 Vessel B RMS and Resistance Table.7 Vessel A RMS and Resistance Table.9 Vessel C RMS and Resistance
Tables 7, 8 and 9 showed that the 0° wave headings gave more bad impact both in the added resistance to the ship due to the hull form in the ship stern is bigger than the form of the bow. Tables 13,14 and 15 also showed that the 90° gave the worst impact due to the existence of the heave, pitch and roll motions, which the 180° and 0° only having heave and pitch motion only.
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« Un ingénieur de la Marine à l’école des constructeurs du « commerce » : Chevillard le cadet à Saint-Malo pendant la guerre d’Indépendance américaine », Stéphane Blond, Liliane Hilaire-Pérez et Michèle Virol (dir.), Mobilités d’ingénieurs en Europe, XVe-XVIIIe siècle, Rennes, PUR, 2017, p. 101-127
by David Plouviez
Au cours de l’année 1777, le secrétaire d’État de la Marine Sartine décrète un programme de construction de dix frégates pour faire face à la guerre qui débute contre l’Angleterre, et choisit Saint-Malo, un port de commerce, pour en... more
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A Gestão do Projeto de uma Canoa de Ferrocimento
by Igino Giordani
Monografia apresentada ao Curso de Graduação em Engenharia Mecânica da Universidade Federal de Pernambuco, UFPE, pelo aluno, Igino Giordani da Silva Guerra, sob a orientação do Professor D. Sc. Juraci Carlos de Castro Nóbrega, como... more
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Outrigger RC Boat Model Hull Development As A High Speed Craft Based On Resistance and Lift Force
by Bagiyo Suwasono and 
2 more
H.M.A. Akbar, A. Sahir
Ali Munazid, ST., MT
A hull development of outrigger RC boat model, which was made as planning hull was carried out numerically. The observation focus on the analysis of resistance and lift force which were produced by the boat while cruising that can enhance... more
Also in this research the boat categorized as a planning hull boat. By definition, a planning hull boat described as a hull form which is configured to develop the positive dynamic pressure, so that it’s draft decreases and with increasing speed. The dynamic lift reduces the wetted surface area and therefore also the drag. Planning hulls are more efficient at higher speeds, although they still require more energy to achieve these speeds [3]. Therefore this research shall focus on the hull development of an outrigger RC model boat which then hoped to be a good start in the power outrigger type boat development. To enhance the accuracy in the results data which will be gathered in this research, the boat shall be conditioned with three different demi-hulls positions with fixed S/L ratio which is 5.45 measured from the main hull outer body to the outer body of the demi-hull and also fixed hull positions differences, one with the aligned forepeak and the other is not aligned which pictured in Fig.1
Fig.2. Lines Plan of Outrigger RC Model. In order to expand the usage of the outrigger boat, a RC power outrigger boat design is developed based on resistance analysis. The principal particulars of the models are shown in Table 1 and Fig. 2.
The simulation in Fig.3 shows that the model A is having less fluids pressure due to a larger S/L ratio anc asymmetric outrigger hulls placement which then leads to a higher turbulence effect (TED and TKE). The difference of the second RC model is that the model B is having lower turbulence effects (TED and TKE) due to the smaller value of S/L ratio and asymmetric outrigger hulls placement, besides that these factors also leads to the pressure enhancement especially in the after peak part of the model. The model C is having the highest value of turbulence eddy dissipation due to the larger S/L ratio and the symmectric outrigger hulls placement. Because of the value of the S/L ratio is the same as model A the approximation of the turbulence kinetic energy value is near. The CFD simulation then used to clarify the total resistance calculation based on the fluids flow model measurements to enhance the accuracy of the results data in this research and the water condition in this research was assumed as smooth water. Based on Savitsky planning theorem in hydrodynamics evaluation of planning hulls in smooth water, it has been found that the flow which separated from the chine may reattach to the side of the prismatic hull at some distance forward of the transom for certain combinations of C,, B, r, and mean wetted length- beam ratio\. An empirical formulation of the slope of the line through the data is [7]:
Table.2 Outrigger RC Model (A) (B) (C) from CFD Results Because of the lift only happen in the first beat of the model’s speed, the research then focused on the first 1 m/s of the RC boat speed, which have the most impact of the lift force that caused by the existence of the hydrodynamic pressure so that the model had a trim moment that can be express mathematically as:
Table 3. Outrigger Model Results From the total and slender body resistance calculations, some results also had been found as follows:
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KONSTRUKSI MELINTANG KAPAL
by Fauzi Imam HD
Length Between Perpendicular ( LPP ) : 96,00 m Breadth ( B ) : 16,20 m Depth ( H ) : 7,80 m Draught ( T ) : 5,60 m Coefficient Block ( CB ) : 0,67 m Data Penunjang z(vertical distance of the structure's load centre above base line ): 7,80... more
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Prognostic enhancements to diagnostic systems for improved condition-based maintenance [military aircraft
by Carl Galy

2002, Pain Medicine

In recent years, numerous machinery health monitoring technologies have been developed by the US Navy to aid in the detection and classification of developing machinery faults for various Naval platforms. Existing Naval condition... more
Figure 1 — Hierarchy of Prognostic Approaches In general, health management technologies will observe features associated with anomalous system behavior and then relate these features to useful information about the system’s condition. In the case of prognostics, this information relates to the condition at some future time. Inherently probabilistic or uncertain in nature, prognostics can be applied to system/component failure modes governed by material condition or by functional loss. Like diagnostic algorithms, prognostic algorithms can be generic in design but specific in terms of application. Various approaches to prognostics have been developed that range in fidelity fom simple historical failure rate models to high-fidelity physics-based models. Figure 1 illustrates the hierarchy of potential prognostic approaches in relation to their applicability and relative costs. This paper will discuss some generic prognostic implementation approaches and provide some specific
H u a ealth management system architectures must allow for the integration of anomaly, diagnostic, and prognostic (A/D/P) technologies from the component level all the way p through the vehicle or platform level. In general, A/D/P technologies observe features associated with anomalous system behavior and relate them to useful information bout component or system condition. Before getting into some specific examples of diagnostic and prognostic techniques applied to different aspects of an air vehicle, a brief description of some of the more common technical approaches are given. The software modules are currently in prototype development stage. Figure 2 - PEDS Plug and Play "Toaster" Model
Figure 3 - Outline of the OSA/CBM Architecture MIMOSA is a not-for-profit trade association founded in 1994 and incorporated in December of purpose is the development and pu conventions for information exchange machinery maintenance information systems. The core o the MIMOSA development activity is t (Common Relational Information Schema). The second 996. Their genera blication of open between plant and he MIMOSA CRIS version of the CRIS (CRIS V2.1) was re and is publicly available at the MIMOSA website [http://www.mimosa.org/]. The CRIS defines a relationa eased in May 2000 database schema for machinery maintenance information. The schema provides broad coverage of the types of data that need to be managed within the CBM domain.
Figure 4 - Experienced-Based Approach has little or no sensed parameters associated with it. In this case, the prognosis of when the component will fail or degrade to an unacceptable condition must be based solely on analysis of past experience or OEM recommendations. Depending on the maintenance complexity and criticality associated with the component, the prognostics system may be set up for a maintenance interval (i.e. replace every 1000+/-20 Effective Operating Hrs) then updated as more data becomes available. Having an automated maintenance database is important for the application of experience-based prognostics.
Figure 6 - Feature/AI-Based Prognostics Utilizing known transitional or seeded fault/failure degradation paths of measured/extracted feature(s) as they progress over time is another commonly utilized prognostic approach. In this approach, neural networks or other AI techniques are trained on features that progress through a failure. In such cases, the probability of failure as defined by some measure of the “ground truth” is required as a-priori information as described earlier. This “ground truth” information that is used to train the predictive network is usually obtained from inspection data. Based on the input features and desired output prediction, the network will automatically adjusts its weights and thresholds based on the relationships between the probability of failure curve and the correlated feature magnitudes. Figure 6 shows an example of a neural network after being trained by some vibration feature data sets. The difference between the neural network output and the “ground truth” probability of failure curve is due to error that still exists, after the network parameters have optimized, to minimize this error. Once trained, the neural network architecture can be used to intelligently predict these same features progressions for a different test under similar operating conditions.
The purpose of this investigation was to identify features tha could be incorporated in an automated system for diagnosing clogged fuel nozzles. The main focus was diagnostics, but there is potential for incorporating a prognostics element giver sufficient clogging progression data. This example focuses largely on a feature-based approach. Figure 8 — Clean Nozzle and One with Severe Clogging Clogging reduces the efficiency of the combustion process and can create potentially damaging hot spots in the combustor and turbine sections. At startup, this is especially true to the extent that “hot starts” or “no starts” may be produced. For this project, Impact Technologies used test data from several start-ups of an Allison 501-K17, taken at NAVSEA Philadelphia, comprising both clean and fouled fuel nozzles.
Figure 7 - Physics-Based Prognostics
‘igure 9 — Feature Diagnostic Scalars at Baseline and under Degraded (Fouling) Conditions
Figure 10 - Borescopic Image of Salt deposits: 1* stage Blading
Figure 11 - Prognostic Model Visualization To manipulate the data into the form of this model, the time dependency of the test results had to be removed because of the unrealistic fouling rates. The percent changes in static pressure ratio, fuel flow, and CDT were recast in terms of 4 % pseudo-efficiency drops. This increment was chosen because it was the highest resolution that still permitted statistical analysis. With the assimilation of the data into these discrete bands, the statistical parameters (e.g., mean and standard deviation) can be ascertained for use in the prognostic model. Figure 11 shows the evolution of the compressor degradation for the LM-2500 test at 1% pseudo-efficiency drops (for visual clarity). The top two plots illustrate the distributions of pressure ratio and fuel flow respectively while the bottom two provide the joint probability distributions. Once the statistical performance degradation path is realized along with the capability to assess current degradation severity, the final step was to implement the predictive capability. The actual unit-specific fouling rate is combined with historical fouling rates with a double exponential smoothing method. This time series technique weights the two most recent data points over past observations. The following equations give the general formulation. (Bowerman, 1993). Figure 12 shows how this technique can give significantly different results than standard regression.
Figure 13 - Gear Model-Based Prognostics Under the Phase I SBIR effort a physics-based model for geartooth failure was developed. It illustrates the physics- based model approach. This model was chosen because it could be validated and calibrated on transitional (run-to- failure) data from the MDTB (Mechanical Diagnostics Test Bed) at the Penn State Applied Research Lab. This prognostic module is a near real-time, self-calibrating. physics-based statistical RUL predictor of gear tooth failure due to tooth spalling or low cycle fatigue (LCF)
Figure 12 - Prediction of Degradation Rates The test data made two essential contributions to the development of this prognostic model. First, it provided a means by which to validate an analytical model of how performance parameters change as a function of compressor fouling. Secondly, they gave insight into the sensitivity and statistical distributions of performance parameters as a function of load. Hence, having been developed and validated on real data, a large amount of knowledge is “built in” to the prognostic model.
Table 1 — Recorded Parameters from the Digital Control System When a compressor undergoes fouling, several key performance factors are affected. The most sensitive of these factors is the compressor capacity or referred mass flow. (Peltier et al, 1995) This is because loss of capacity comes from throat blockage and increases in roughness on the suction side of the blading. Unfortunately, in most practical naval applications, compressor capacity is not reliably determinable. The compressor inlet temperature (CIT), outlet temperature (CDT), inlet total pressure (CIP;) and discharge total pressure (CDP;) can typically be used to find compressor efficiency. (Boyce 1995) However CDT, CDP; are not standard sensors in most Naval platforms.
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Caveat Emptor - Building Ireland’s Small Navy 1945-49, pp 141-153.
by John Treacy
Over recent years, the Irish Naval Service has experienced an unprecedented and accelerated process of naval fleet replenishment, resulting in a fleet redefined by smart technologies. The P61 class marks a paradigm shift in long... more
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URANS Study of Delft Catamaran Total/Added Resistance, Motions and Slamming Loads in Head Sea Including Irregular Wave and Uncertainty Quantification for Variable Regular Wave and Geometry
by Matteo Diez and 
2 more
Daniele Peri
Yusuke Tahara

2012, 29th Symposium on Naval Hydrodynamics, Gothenburg, Sweden

A methodology is assessed for uncertainty quantification (UQ) of resistance, motions and slamming loads in variable regular wave representing a given sea state, and compared to irregular wave (benchmark) and deterministic regular wave... more
Figure 1; Lines plan of the Delft cat. 372.
Figure 4: Slamming loads; identification from pressure time-history (a); selection of pressure probe (b,c) and identification threshold (d) for current slamming studies. Max. emerging (e,f) and re-enetring (g,h) slams including pressure distribution. Figure 3: Amplitudes and periods for generic variable V(t).
Figure 5: Empirical versus theoretical CDF for (a) wave period T and (b) wave height H in sea state 6.
Figure 8: RAOs for AR (a,b), AC; (c,d), as function of encounter frequency f, and non- dimensional wavelength 1/L.
‘igure 9: RAOs for non dimensional heave z/L (a,b), and pitch 6 (c,d), as function of encounter frequency f, and non- dimensional wavelength //L.
Figure 10: Phase for non dimensional heave z/L (a,b), and pitch 6 (c,d), as function of encounter frequency f, and non- dimensional wavelength //L.
Figure 11: Energy spectrum of inlet boundary condition for sea state 6: (b) from raw FFT and (c) using best-fit.
Figure 13: FET of force X (a) non-dimensional pitch z/L (b) and pitch 6 (c) in sea state 6, at Fr=0.5.
Figure 15: Comparison of time history PDF for irregular wave benchmark and variable regular wave UQ. Empirical anc Normal density functions are shown: (a) force X, (b) heave 2/L, (c) pitch 6.
Figure 16: 2D UQ for variable regular wave: PDF of (a) force mean, mean-crossing amplitude for heave (b) and pitch (c) motions. Empirical distributions are compared with Normal (time mean) and Gamma (amplitudes).
‘igure 21: 1D UQ for variable geometry in calm water: PDF of (a) total resistance coefficient, (b) sinkage and (c) trim. Empirical distributions are compared with Beta.
Figure 19: 2D UQ forvariable regular wave: PDF of (a) emerging pressure jump and (b) re-entering pressure jump. Empirical distributions are compared with Gamma. ‘igure 18: UQ items; first and second harmonics amplitude of force coefficient X versus wave period and height (a,b) and versus encounter frequency and wave amplitude (c,d). Polyharmonic spline (k=2) is used to get contours. Black dots are MCMC items.
Figure 20: Geometric UQ: upper bound geometry for first KLE direction, (a) side [yellow], (b) bow and (c) stern views [dotted]; in green the original geometry.
figure 22: 1D UQ for variable geometry in deterministic regular wave: PDF of (a) force mean, mean-crossing amplitude for heave (b) and pitch (c) motions. Empirical distributions are compared with Beta.
gure 24; 3D UQ for variable regular wave and geometry: PDF of (a) force mean, mean- crossing amplitude for heave (b) and pitch (c) motions. Empirical distributions are compared with Normal (time mean) and Gamma (amplitudes). Figure 23: 1D UQ forvariable geometry in deterministic regular wave: PDF of (a) emerging pressure jump and (b) re- entering pressure jump. Empirical distributions are compared with Beta.
igure 25: 3D UQ for variable regular wave and geometry: PDF of (a) emerging pressure jump and (b) re-entering pressure jump. Empirical distributions are compared with Gamma.
Table 2: Sea states probability and spectrum parameters.
Table 3: Irregular wave inlet boundary condition: empirical distributions vs. theory for sea state 6.
Table 4: Comparison of theoretical and empirical values for Bretschneider spectrum in sea state 6.
Table 6: Verification and validation for calm water simulation at Fr=0.5; S; is solution of G1 or G2 and D is INSEAN EFD.
Table 7: Calm water simulation of Delft catamaran, Fr=0.5, Re=7.14x10°.
Table 8: Verification for Delft catamaran at Fr=0.5 in regular wave at T,, H) for sea state 6. Table 9: Simulation for Delft catamaran at Fr=0.5 in regular wave at T,, H, for sea state 6.
Table 10: Relevant parameters for Delft catamaran at Fr=0.5 in regular wave at T,, Hy for sea state 6.
Table 12: Statistical analysis of slamming loads and waves from irregular wave benchmark (probe B1).
Table 14: Variable regular wave (SS6): MC study for slamming loads.
Table 15: Comparison of deterministic regular wave (T), Hp) and UQ versus irregular wave benchmark.
Table 17: Comparison of slamming loads for deterministic regular wave (T,, Hp) and regular wave UQ versus irregula wave benchmark. Table 18: Metamodels ranking for variable regular wave and original geometry: 2D UQ for resistance,and motions
Table 19: Variable geometry in calm water: MC study for resistance, sinkage and trim.
Table 20: Variable geometry in deterministic regular wave (T,,H,): MC study for resistance and motions.
Table 21: Variable geometry in deterministic regular wave (T,,H,): MC study for slamming loads.
Table 22: Variable regular wave (SS6) and geometry: MC study for resistance and motions.
Table 23: Variable regular wave (SS6) and geometry: MC study for slamming loads.
Table 24: Metamodels ranking for variable geometry in calm water: 1D UQ for resistance, sinkage and trim.
‘able 25: Metamodels ranking for variable geometry in deterministic regular wave (T,,H,): 1D UQ for resistance, heave and pitch motions. Table 26: Metamodels ranking for variable regular wave and geometry: 3D UQ for resistance and motions.
Table 27: Metamodels ranking overall (average of UQ problems for resistance and motions)
Table 28: Added resistance and energy consumption at different sea states and Fr=0.5.
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Statistical Validation of a High-speed Catamaran in Irregular Waves
by Matteo Diez

2016, 31st Symposium on Naval Hydrodynamics

The paper presents an improved statistical validation method for irregular wave simulations, with application to the Delft catamaran at Fr=0.425 and (scaled) sea state 5. The procedure is based on non-overlapping and moving block... more
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Tunç Çağı Sonunda ilk Deniz Savaşları / The Beginning of Naval Warfare and the End of the Bronze Age (Aktüel Arkeoloji 41, pp. 28-39), 2018
by Jeff Emanuel

2018, Aktüel Arkeoloji

Throughout human history, the sea has served as a means of subsistence, transportation, and communication, as well as a place of danger and death. From the time ships first set out with cargo on board, there have probably been pirates... more
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ownership cost drivers in ship design and construction
by Guedj Youri and 
1 more
Peter Sanders
There is a perception that Naval ships cost too much to buy, specify, operate, maintain, sustain and dispose of. The reality or otherwise of this perception can only be determined through a structured cost analysis approach. Through the... more
Figure 1 - Time Related C ost Impacts Figure 1 gives a qualitative indication of the cost impact of decisions throughout a generic acquisition process. This relationship is well known, understood and is essentially intuitive. However, in practice many of the approaches taken in. ship design do not adhere to the principles and practices this relationship alludes to.
Figure 3 - Andrew's Overall of Ship Design Process
“The ultimate goal of the Axiomatic Design is to establish a science base for design, and to improve design activities by providing the designer with a theoretical foundation based on logical and rational thought processes and tools.” [5]. While the classic and intuitive engineering design process is iterative, the Axiomatic Design process consists of generating basic and independent requirements, and focuses on selecting the best means to achieve the requirements. It breaks down a complex engineering problem into "simple" sub-problems, which are easier to solve: Axiomatic Design is a systems design methodology using matrix methods to systematically analyse the transformation of customer needs (CRs) into functional requirements (FRs), design parameters (DPs) and process variables (PVs). The methodology has been in development since 1990 by Dr. Suh Nam Pyo at MIT, Department of Mechanical Engineering [5]. The product development process is divided into four domains that are connected by three mappings, as shown in Figure 5.
Figure 4 - Cost/Performance trade off So, in simple terms the objective is to set up a series of models and decision matrices to allow a trade-off between ownership costs and effectiveness/performance. This concept is illustrated in Figure 4.
Figure 6 summarises the mapping process applied to ship Jesign after basic ship requirements have been defined (cf. Table 1). Figure 6 Axiomatic Approach A pplied to Naval Engineering Table 1 - High Level Customer Requirements
The process starts with the design of ship's systems that define the weight, space and area requirements. The hull is finally designed using the quantities imposed by the design of the ship's systems (DP1, DP2, DP3, DP4, and DP 5) and the performances defined by the customer attributes (CAs). The resulting synthesis model process is shown in Figure 7. The above operation allows the representation of a simplified and systematized design, where the influence of a design parameter on the functional requirements is well defined, and understood.
By this means, ship system costs are optimised during the design process and overall ship cost is assessed when the design has converged. This is a complex process for Naval ships. Figure 8 - Cost Oriented - Functional Ship Design Process (BMT D&T)
Figure 9 Set-Based Design process [10] For each system, the ranges of solution and associated requirements on other systems are communicated to each engineering discipline. Regions of feasibility are assessed by intersection of the different range of solution (cf. Figure 9). The range of solution for each discipline is reduced by elimination of subsystems solution that do not contribute to the total system solution. As the design space reduces in size, the level of detail increases and risk and cost estimates are evaluated with increasing accuracy.
designers. Instead of trying to modify the initial concept to reach convergence and stability of design, the process focuses on designing the appropriate hull form to support the ship's systems. The ship is a platform that supports various complex systems and allows them to be moved through the water with performances fixed by the designer.
Figure 11 - Example of Fuzzy Logic
Figure 12 - Block C oefficient Definition
The application of the axiomatic approach to the early ship design stages consists of first identifying the constraints governing the design, then identifying the functional requirements and the associated design parameters.
Table 4 - Additional Design C onstraints Their analysis results in the formulation of a decoupled design, illustrated by a lower triangular design matrix (cf. Equation 2) where the Independence Axiom is respected and the Information Axiom is satisfied.
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Naumachiae in roman amphitheatres – myth or reality ? in: International Archaeological Symposium: "Navigare necesse est: from Prehistory to the Early Middle Ages" / Međunarodno arheološko savjetovanje "Navigare necesse est. Od prapovijesti do ranog srednjeg vijeka", Materijali, vol. 23, Pula 2011.
by Marin Buovac
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The Entry of History in Naval Science
by Massimo Corradi
The writings that most closely belong to the discipline of history, and in particular the history of shipbuilding, are papers containing arguments quite different from each other, or very informative or very specialized. The scientist is... more
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Ship hydrodynamic optimization by local hybridization of deterministic derivative-free global algorithms
by Matteo Diez and 
3 more
Andrea Serani
Umberto Iemma
Fasano Giovanni
Simulation-based design optimization methods integrate computer simulations, design modification tools, and optimization algorithms. In hydrodynamic applications, often objective functions are com-putationally expensive and noisy, their... more
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Regulasi yang Berkaitan dengan Machinery Installations pada Kapal Khusus (Special Purpose Ships)
by Arnan Abdurrofi
Pada dasarnya dalam mererncanakan sebuah kapal, semuanya harus memenuhi syarat-syarat regulasi, tujuan dari dirancang dan diterapkannya regulasi tersebut salah satunya untuk keselamatan kapal itu sendiri karena menyangkut kehidupan orang... more
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La battaglia di Desenzano del 1439 e la Val Lagarina (Galeas per montes), "Quaderni del Borgoantico", 17, 2016, pp. 59-61
by Paolo Cont
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Aprovisionando de madera el arsenal de Cartagena: el proyecto de Manuel Bernia y las flotaciones por el río Segura (1784-1793)
by María Amparo López Arandia
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A ring vortex free wake model for uniformly loaded propellers Part I - Model description.
by Rodolfo Bontempo and 
1 more
Marcello Manna

2018, Energy Procedia

District heating networks are commonly addressed in the literature as one of the most effective solutions for decreasing the greenhouse gas emissions from the building sector. These systems require high investments which are returned... more
Figure 1. Sketch of the rotor vortex model. Left: Joukowsky model. Right: vorticity decomposition.
Figure 3. Sketch of the discrete wake vortex model in a meridional view. Figure 4. 3D sketch of the ring vortex set-up.
Figure 3. Sketch of the discrete wake vortex model in a meridional view.
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The Career of the Indies
by Fernando A P Pereira
The Career of the Indies was the culmination and simultaneously turning point in Portuguese expansion. Indeed, the Portuguese Discoveries were started with the ultimate goal of reaching the mythical Indies, lands that have always... more
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Hydrodynamic ship design optimization considering uncertainty
by Matteo Diez

2015, NAV 2015, 18th International Conference on Ships and Shipping Research, Lecco, Italy

The development of advanced and efficient tools for uncertainty quantification and design optimization under uncertainty of ships operating in a real scenario are described. Under the assumption that objective functions and constraints... more
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Design optimization of the waterjet-propelled Delft catamaran in calm water using URANS, design of experiments, metamodels and swarm intelligence
by Matteo Diez

2013, 12th International Conference on Fast Sea Transportation, FAST2013, Amsterdam, The Netherlands

A URANS-based design optimization for the waterjet-propelled Delft catamaran is presented. Iterative Latin hypercube and Hammersley sequence are used to generate initial designs; multiple metamodels are applied to reduce the computational... more
Figure 1: Delft catamaran barehull, original vs. optimized (Chen et al., 2013
Figure 2: Waterjet design optimization flow-chart
Figure 3: Overset grids for hull and waterjet duct and nozzle
Figure 4: Waterjet design space (a) including gp (original WJ), g; (WJ-1) and g, (WJ-2), and sensitivity analysis (b)
Figure 5: Surrogate-based design optimization using iterative LHS with M = 9 (a), 17 (b), 33 (c), 65 (d). Contours are made by PHS
Figure 6: Surrogate-based design optimization using HSS for global DoE (a), M = 40, and refinement (b), M = 60. Contours are made by PHS
Figure 7: PSO convergence for objective function (a) and optimal design variables (b) using SRBF.
Figure 8: Original (a) and optimized (b) waterjet designs
Table 2: Particle swarm optimization coefficients
Table 5: Performances of optimized design
Table 4: Summary of optimization results
Table 3: Grid size for waterjet propelled Delft Catamaran
Table 1: Delft Catamaran main particulars (372 original model) and conditions Note: Length parameters without unit are normalized by L,,
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Armando Marques Guedes (2018), Economia, Política, e Voluntarismo. A distribuição dos clusters dos pontos de amarração dos cabos de fibras ópticas submarinas na Bacia do Atlântico e a retoma de uma centralidade de Portugal em nexos marítimos recriados (Jornal da Economia do Mar)..docx
by Armando Marques-Guedes
draft do artigo a ser publicado em meados de Julho 2018 num número especial do Jornal de Economia do Mar
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CFD-based multiobjective stochastic optimization of a waterjet propelled high speed ship
by Matteo Diez and 
1 more
Yusuke Tahara

2014, 30th Symposium on Naval Hydrodynamics, Hobart, Tasmania, Australia

The paper describes the development and demonstration of Simulation Based Design (SBD) methods, which have been developed through the long-term international collaboration among three institutes. The methods are capable to solve... more
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