Naval Engineering

Proposed ship-based long-range electromagnetic guns require input energies greater then 100 MJ, at peak powers in excess of 50 GW, and at average power in the tens of megawatts. This paper describes a conceptual pulsed-power system for driving these types of guns. A generic design was developed based on state-of-the-art power-supply, capacitor, and switching technologies. Results of modeling and parametric studies are presented, and key issues that impact system size and configuration are explored. An assessment is made of the feasibility of integrating this type of system into an electric-drive ship.

MGPS Cofferdam is an equipment to be attached at the submerge part of the ship’s hull, to create an watertight environment for the safety cutting, welding, or another underwater activities. The activity here for the MGPS Cofferdam is the changing of the rise pipe at side of the submerged part of hull.

A one-dimensional non-intrusive Polynomial Chaos (PC) method is applied in Uncertainty Quantification (UQ) studies for CFD-based ship performances simulations. The uncertainty properties of Expected Value (EV) and Standard Deviation (SD) are evaluated by solving the PC coefficients from a linear system of algebraic equations. The one-dimensional PC with the Legendre polynomials is applied to: (1) stochastic input domain and (2) Cumulative Distribution Function (CDF) image domain, allowing for more flexibility. The PC method is validated with the Monte-Carlo benchmark results in several high-fidelity, CFD-based, ship UQ problems, evaluating the geometrical, operational and environmental uncertainties for the Delft Catamaran 372. Convergence is studied versus PC order P for both EV and SD, showing that high order PC is not necessary for present applications. Comparison is carried out for PC with/without the least square minimization when solving the PC coefficients. The least square minimization, using larger number of CFD samples, is recommended for current test cases. The study shows the potentials of PC method in Robust Design Optimization (RDO) and Reliability-Based Design Optimization (RBDO) of ship hydrodynamic performances.

En este trabajo de fin de máster, se ha realizado una evaluación de riesgos laborales en buques mercantes, para proponerlo como un modelo y estandarizar el proceso llevado a cabo.
El proceso de evaluación de riesgos, se basa en la evaluación general de riesgos que el Instituto Nacional de Seguridad e Higiene en el trabajo expone en su manual de referencia.
Debido a la alta siniestralidad de los incendios ocurridos a bordo de los buques mercantes, se ha realizado un análisis del riesgo de incendio.
Una vez realizada la evaluación de riesgos, se han identificado aquellos riesgos catalogados como moderados e importantes y se exponen las medidas necesarias a implantar con el objetivo de eliminar o reducir y controlar dichos riesgos.

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 often embarrassed in reading these books because they are written from a humanistic, and they are not scientific-technical papers, sometimes they are complemented with mathematical formulas and diagrams written in obsolete languages, designed to discern the paths of history passed, and adjacent to a discipline that looks to the near future and not in the past, a history too often forgotten. The Scientia navalis or Naval Science, which Leonhard Euler (1707 - 1783) was a teacher and somewhat precursor, from time immemorial languishing on the shelves of libraries, neglected by scholars. This occurred because the discipline has come to self-awareness, especially in the contemporary age, when, following the example of the Galilean revolution, the community of surveyors and scholars of mechanics oriented his attention to the problems of shipbuilding and vessel operations, which at first seemed disciplines entrusted only to the skill of the shipwright, carpenters and the Masters and Shipmasters on board ships, as well as to the wisdom of tradition. History, however, is a fascinating and fruitful field of study for some guidance because by understanding what has been achieved in the past, has been able to establish a more consistent definition of science and technology to be used in applied in the design and construction. Even for shipbuilding, in fact, the sedimentation of knowledge of the past passed down orally by the shipwright to their students and then taught in the schools of Naval Engineering in France scrolls and founded by Jean- Baptiste Colbert (1619 - 1683) Secretary of the French Navy in the seventeenth century, has been able to point the way to address and solve static and structural problems, but also those related to material behaviour and then, thanks to the Enlightenment of the eighteenth century, those relating to navigation and manoeuvring of vessels. Only in this way it was possible to achieve those goals of technical and technological developments that have allowed the massive shipbuilding industry in the nineteenth century, following the same “logic” that guided the ancient builders and shipwrights, thus obtaining accurate and effective design and construction solutions.

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 prototype hydrofoil craft. The thesis objective is to develop a control law that when combined with a careful integration of mechanical and electronic components, can maneuver the hydrofoils. Optimal linear quadratic regulators and PID control were the methods utilized. Successful foil control laws were obtained. The foil control system achieved is intended to serve as the foundation for craft motion control, a necessary element for applications in marine dynamics.

The paper investigates on the effects of the hydrodynamic solver on the multi-objective hull-form optimization of the DTMB 5415 model in calm water. Potential flow and RANS are compared. The former is formulated and implemented using two linearization approaches (Kelvin and Dawson), combined with two methods for the wave resistance. The Pareto fronts for the reduction of the resistance at two speeds are obtained by a multi-objective particle swarm optimization and are significantly affected by the potential flow formulation. A correlation analysis with RANS is shown, in order to suggest the most effective potential flow formulation for the present case.

Pre-and post-swirl fins-based energy-saving devices (ESD) are designed to improve the propulsive performances of a twin-screw ship. To this aim, BEM and RANSE calculations are employed. Depending on the application, a simple actuator disc model (post-swirl) with radially varying load or a combined BEM/RANSE method for self-propulsion prediction (preswirl) are required. Both the approaches are included in a framework for a design by optimization, where systematic variations of the ESD geometry are used to explore the design space and maximize the energy-saving effect of the devices. Considering the particularity of the case selected for the study, results show encouraging improvements that reach a promising 5% in the case of the combined action of both devices.

Métodos de arqueo en el siglo XVL por José Luis Rubio Serrano29 Las dos piedras con naves en relieve de la catedraly torre inclinada de Pisa, por Laureano Carboneil Relat.... 71 La lucha anticorsaria en Valencia durante la Edad Media. El episo dio protagonizado por Pere Cabanyelles, por Andrés Díaz Borras105 Establecimiento del asiento de avería en el comercio de Indias, por

This article discusses several minor refinements to Titanic's design based on experience with some specific riveted joints on Olympic (similar changes were then incorporated into Olympic and Britannic).  It is a greatly expanded version of an article originally made available on the Titanic Research & Modelling Association (TRMA) website in 2005, which published information about these changes for the first time.  This expanded article appeared in the British Titanic Society journal Atlantic Daily Bulletin in December 2019.

NASCITA ED EVOLUZIONE DEI CONTAINERS

Una rivoluzione recente quella dei containers e del trasporto marittimo degli stessi, una rivoluzione strisciante che oggi è diventata condizione del benessere, una rivoluzione scarsamente percepita dall’ opinione pubblica sino a che la sua importanza non è apparsa in tutta la sua gravità e implicazioni in occasione dell’ incaglio di una mega-portacontainers nel canale di Suez.
Oggi si parla di portacontainer da decine di migliaia di TEU, numero enorme di “pezzi” la cui movimentazione richiede una organizzazione complessa ma anche capillare, attenta ai minimi dettagli, nonché una attenta gestione tecnico-nautica della nave
Al gigantismo delle “navi madre” che possono solo scalare terminali attrezzati, sempre più specializzati, si è aggiunto il controllo di questi “snodi” da parte  della stesse “mani”, pochi operatori che, abbiamo visto nella “prova generale” del blocco del Canale di Suez, possono mettere in ginocchio l’ economia mondiale, agendo su poche leve di comando.

Come si è giunti a questo? come premessa ad un’ analisi di questa situazione, è utile conoscere come, in pochissimi anni, si sia arrivati a questa gestione degli scambi, in particolare per la parte marittima.

Questo articolo è stato originalmente richiesto, a fini divulgativi,  da Italian Shiplovers per pubblicazione nel dicembre 2020

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 yang ada dikapal. Begitu juga dengan Special Purpose Ships (SPS) juga harus memenuhi persyaratan regulasi yang berlaku. Kali ini Penulis akan memaparkan lebih lanjut kaitannya dengan regulasi SPS kaitannya dengan Machinery Installations yang akan dijelaskan dalam Bab Pembahasan.

The Future Frigates Program SEA 5000 is the largest naval shipbuilding project in Australian history, the centre piece of the continuous National Naval Shipbuilding Enterprise. This paper, by former Parliamentary Secretary for Defence David Feeney shows that Australia will be paying nearly double per frigate as compared to the contemporary US and UK Frigate programs. Even though the Strategic Update 2020 highlights Australia’s rapidly deteriorating strategic environment, Feeney shows the Government has deliberately structured the frigate program so that it delivers capability more slowly (extended to 2044) and at greater cost (an additional A$9.3 billion). He argues the key reason for this deliberate slow down in the construction rate of the frigates is to enable the “implementation of a stable, deliberate and continuous shipbuilding drumbeat” so as to “end the ‘boom and bust’ cycle of naval shipbuilding, delivering sovereign capability and certainty for industry.” The paper explores the challenges of shipbuilding, the policy tensions and trade offs, and offers suggestions for how to get SEA5000 back on track.

The method of analysis of cavitation in marine propellers that takes into account the Burrill Diagram is one of the most used by designers worldwide. The literature has reported this technique as reliable and quite useful in the design of fixed pitch conventional propellers. However, an accurate execution of the method shows that the calculations for cavitation at 2.5% on the back of the blades can indicate this percentage as having happened after cavitation at 10% or even after cavitation at 20%, which makes it physically impossible. In  addition,  there  may  be  negative  values of  expanded  area,  which  results  in  a  wrong indication of cavitation. In this sense, cavitation prediction calculations for five diameters were performed: a small commercial component of 0.25 m, a large of 10 m, belonging to a large oil vessel and three intermediaries, for comparison of results and reinforcement of conclusions. Within the examples of propellers tested, it was possible to conclude that the Burrill  Diagram  works  well  for  constructive  blade  angles  between  60  and  67  degrees, paired  with  a  45-degree  angle,  with  an  inclination  to  the  left.  But  most  of  the  time,  it provides false indication of cavitation for angles less than 60 degrees and greater than 67 degrees. It was also possible to verify that the larger the propeller diameter, the smaller the error range in the 2.5% cavitation indication. In view of these facts, the Burrill Diagram method does not become invalid, but it is concluded that it must be used with due care, within the indicated safety range.

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 CFD/CSD (computational fluid dynamics/ computational structural dynamics) FSI is shown for composite bottom panels with different layout and resulting stiffness. The CFD is performed using the code CFDShip-Iowa, whereas the CSD implements a modal expansion based on modes and frequencies predicted by the commercial FE code ANSYS. One-and two-way (tightly coupled) CFD/CSD FSI is performed using deterministic captive regular-wave simulations, modeling the sea trial conditions. Simulations provide details of slamming events, including correlation of re-entering and emerging pressure peaks with motions and correlation of pressure and strain peaks. Statistical estimators of experimental pressure and strain are used for the validation. Errors between deterministic CFD/CSD FSI and sea trial expected values are fairly large and equal on average 19%. However, experimental uncertainties from aleatory sea conditions are also large. For all cases and validation variables, errors are always smaller than the standard deviation of experimental data. The main effect of the two-way coupling is the reduction of pressure and strain peak values. Numerical and modeling issues are identified for both CFD (spatial and temporal resolution, environmental and operating conditions) and CSD (damping). The current results are overall promising, laying the groundwork for long term research on development and validation of high-fidelity two-way CFD/CSD FSI, including extensions to multidisciplinary optimization (MDO).

The U.S. Navy is considering developing an electromagnetic railgun for use on future ships for long-range shore bombardment missions. The goals are to provide support for ground forces in a timely fashion, increase the ship-to-shore standoff distance, and improve ship survivability in combat situations. This paper describes the parameters of a notional railgun design that may be capable of supporting the Navy's needs. The Naval Surface Fire Support mission requires a railgun capable of firing high-energy projectiles for ranges of 300-500 km with a firing rate of up to 12 rounds per minute. The notional system described here is intended to meet these requirements while providing the ability to take advantage of the integrated electric drive architecture to be used on the next generation destroyer. Several important technology issues will need to be addressed before the feasibility of such a system can be demonstrated. These issues are identified and discussed.

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 muntuk menghitung beban geladak cuaca CRW( service range coefficient ) : 1 ( for unlimited service range )

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 archaeological and historical evidence pertaining to the application of copper and lead sheathing by the Dutch long-distance trading companies outlines the argument for the innovative character, experimental use—on ships’ hulls—and standardization—on sternposts—as early as 1602. Archaeological evidence presented mainly comes from the Dutch East Indiamen Nassau (1606), Mauritius (1609), Batavia (1629), Vergulde Draak (1656), and Buitenzorg (1760).

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, documentos da época e nas peças encontradas no fundo do rio Tejo junto ao forte de São Julião da Barra (referentes a uma nau naufragada em 1606), é possível estabelecer configurações plausíveis para o desenho das formas do casco e aparelho destes navios, e testá-los por meio de processos científicos, em ambientes controlados.

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 singolo, o di un gruppo Nessuna intenzione di trattare ancora né di elettronica, frequenze e prestazioni né di scontri il cui successo sia stato condizionato dal radar; ... solo una serie di spunti, basati non sulla definizione di quali studi o progetti fossero più o meno avanzati o validi, da una parte o dall' altra, sugli aspetti industriali, su quanto e come nuovi concetti si fossero veramente trasformati in tecnologie e, ancora più importante in dottrine di impiego, da lì, quanto e come avessero avuto pratica applicazione in produzioni industriali ed in quali serie, con quali aspettative e soprattutto con quale accettazione. Non voglio né tanto meno posso parlare di prestazioni ma solo di diffusione degli apparati, in primo luogo dal punto di vista delle serie industriali e di allestimento delle unità Un lavoro sui radar sviluppato da un GN appare certamente strano se non fuori luogo: non deve preoccupare, non parlo né degli " apparecchi " né del loro funzionamento, sempre per me molto misterioso con quegli ingombranti, ed anche un po' pretestuosi ed esigenti, scatoloni con cui mi confrontavo a bordo, ma del radar come sistema integrato e di cosa ha comportato studiarlo, industrializzarlo, metterlo a bordo, utilizzarlo ed adattarsi a questo invadente vicino… Troppi libri zeppi di dati e di tabelle (per ingannare) scritti da personaggi che né sono mai stati su una nave né hanno la minima idea di cosa fosse in effetti un radar all' epoca … …ed anche in merito agli apparati radar " Gufo " , frettolosamente prodotti e tardivamente imbarcati sulle nostre navi maggiori, i racconti di quelli che li avevano " vissuti " citano solo caratteristiche mediocri, da far disperare i comandi in merito alla loro reale operatività, in continua contestazione con l'industria che li costruiva.

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 awak kapal yang tidak memperhatikan perhitungan stabilitas kapalnya sehingga dapat mengganggu kesetimbangan secara umum yang akibatnya dapat menbyebabkan kecelakaan fatal seperti kapal tidak dapat dikendalaikan, kehilangan kesetimbangan dan bahkan tenggelam yang pada akhirnya dapat merugikan harta benda, kapal, nyawa manusia bahkan dirinya sendiri. Sedemikian pentingnya pengetahuan menghitung stabilitas kapal untuk keselamatan pelayaran, maka setiap awak kapal yang bersangkutan bahkan calon awak kapal harus dibekali dengan seperangkat pengetahuan dan keterampilan dalam menjaga kondisi stabilitas kapalnya sehingga keselamtan dan kenyamanan pelayaran dapat dicapai. Modul Menghitung Stabilitas Kapal sebagai bagian dari Kompetensi Bangunan dan Stabilitas Kapal yang pada dasarnya merupakan materi kurikulum yang berfungsi untuk mengembangkan kemampuan siswa SMK Bidang Keahlian Pelayaran Niaga, dan untuk diterapkan ketika berdinas diatas kapal khususnya dalam tugas-tugas menjaga kondisi stabilitas kapal yang dapat berpengaruh terhadap keselamatan pelayaran. Modul ini di dalamnya berisi materi yang disajikan dalam beberapa bahan Kegiatan Belajar yaitu :

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 satunya yaitu pembentukan blok – blok badan kapal yang dilakukan di building berth. Kemudian blok-blok tersebut disatukan menjadi blok yang  lebih besar di assembly area. Aktivitas penyambungan blok-blok kapal tersebut tidak lepas dari aktivitas pengelasan. Proses pengelasan ini sangat penting dikarenakan untuk melakukan joint bagian-bagian hull kapal. Dimana dalam proses pengelasan (welding) tidak boleh ada kesalahan sekecil apapun baik berupa crack, over heat, dan sebagainya. Proses pengelasan ini merupakan bagian yang amat vital dalam proses pembangunan kapal.
Maka dari itu dalam proses pengelasan diperlukan hal-hal yang harus diperhatikan oleh para surveyor dan para welder. Dalam makalah ini akan dibahas mengenai beberapa hal yang berkaitan dengan welding.

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 assessment systems such as ICAS (Integrated Condition Assessment System) employ several fault detection and diagnostic technologies ranging from simple thresholding to rule-based algorithms. However, these technologies have not specifically focused on the ability to predict the future condition (prognostics) of a machine based on the current diagnostic state of the machinery and its available operating and failure history data. An advanced prognostic capability is desired because the ability to forecast this future condition enables a higher level of condition-based maintenance for optimally managing total life cycle costs (LCC). A second issue is that a framework does not exist for "plug-and-play" integration of new diagnostic and prognostic technologies into existing Naval platforms. This paper outlines such prognostic enhancements to diagnostic systems (PEDS) using a generic framework for developing interoperable prognostic "modules". Specific prognostic module examples developed for gas turbine engines and gearbox systems are also provided.