High performance marine glass can be characterized as a product that offers safety from accidental or intentional breakage, as well as resilience over time. The composites that fall into this category often include strengthened glass, tough, durable interlayers that bond the glass, and coatings that provide improved solar optical performance. In addition, the laminate composites deliver acoustical benefits, as well as security benefits beyond the basic safety performance of the material. This paper presents the components that comprise high performance marine glazing, the testing that the products go through, and examples of yachts and vessels that have incorporated high performance features into their glazing specifications.

Offshore wind energy is developing rapidly in the United States, particularly off the East coast, which has an extensive continental shelf and where the water depths are such that wind turbines founded directly on the seabed are the most attractive. Of the various foundation configurations that are feasible, it is the monopile that is expected to be most widely used. Another feature of the US East coast is that it is hurricane-prone region, which poses some unique challenges to designers. This paper summarizes research work undertaken to investigate how the role of modern optimization techniques can contribute to the design of such installation and does not establish any realistic project related implications. The project addresses the design of a 15 MW turbine, which represents the upper limit capacity of currently available wind turbines.

The PoNA USV represents the first Unmanned Surface Vehicle built for the Portuguese Navy in collaboration with Arsenal do Alfeite, S.A. and CINAV (the Portuguese Navy's naval research centre). This vessel reflects the current decade's newfound interest and investment in the development of unmanned platforms for military applications by NATO's Armed Forces. Featuring a catamaran hull shape and a versatile modular central platform, this 3.4 meter long vessel is designed to be employed in a wide array of missions and scenarios by the Portuguese Navy. It's innovative modular structure allows custom payloads up to 140kg to be easily exchanged in the field allowing the USV to be employed in different tasks accordingly. The following paper describes the entirety of the design development process for the USV, from concept development to the detailed design according to MCA standards for multi-hull vessels, as well as the ensuing construction and sea trials of the USV, integrating both composite materials and aluminium in its construction. All the design and manufacture challenges faced through this process are also detailed in the paper. From the development of spreadsheets for initial sizing, power predictions and hull resistance, the use of CAE software for design, hydrostatic and stability analysis, loading condition calculations and finite element analysis purposes. Resistance tests in the Portuguese Naval Academy's Ship Model Tank are also expanded upon in the paper, along with the design and construction of a simple sensor for the model resistance tests. The use of 3D printing for rapid prototyping is also addressed in this work. The PoNA USV is currently under design development in the Portuguese Naval Academy and is due to enter service in the summer of 2020.

Weld residual stresses on ship structures were significantly investigated by taking a three-step approach. Step 1 is to measure residual stress on small samples in laboratories to validate measurement methods, Step 2 is to measure residual stress on three test panels made of DH36, HSLA-65, and HSLA-80 in a shipyard, and Step 3 is to measure residual stress on a large mock-up unit and on a tie-down. Step-1 and Step-2 study, presented in SNAME-2017 conference, concluded that portable x-ray equipment can be used in a shipyard environment to provide reliable measurements. Residual stress measurements were successfully measured on small welded joints, DH36 panel, and HSLA-65 panel, but not on HSLA-80 panel. The reason for poor measurements on the HSLA-80 panel was that the primer on HSLA-80 surfaces blocked the diffracted x-ray. To achieve a good measurement, mechanical grinding and electro polishing were investigated to remove the primer before measurement. The least electro polishing time required to remove the compressive stress induced by mechanical grinding was established by experimental trials. With the electro polishing process, reasonable measurements were achieved on the HSLA-80 panel, a tie-down, and the knuckle joints of the large mock-up unit. This paper reports the measured stresses on HSLA-80 panel, the tiedown, and the knuckle joints.

According to the International Maritime Organization performance standards for protective coatings, it is mandatory to manage the paint condition on the surfaces of cargo hold and ballast tanks of a ship. Since this surface coating can be damaged by burning during welding work while building a ship, it is necessary to understand the conditions in which backside burning occurs and to accordingly consider precautions against backside burning. In this study, we develop a method to evaluate prevention measures against backside burning by conducting welding experiments and constructing a computer simulation.

The aim of this study is to design an alternative rescue outfitting system for saving the castaways from the sea. The proposed outfitting rescue system is capable to board the refugees from the sea in short period of time and to manage the rescue operation in high security level against the possibility of injuries. The study includes the basic calculations of the rescue vessel as well as the design of the rescue outfitting system. The system can be used by similar vessels, which are working on the rescue operations for the refugees from the open sea or coastal areas.

Based on the tooling for a Sea Ray 240SD, a specific hull structure was designed which utilizes the concepts of Membrane Hull Technology (MHT). This study discusses the effects that the changes in framing and hull shell laminate thickness have on the weight and structural response of the hull, as well as the cost benefits. MHT involves increasing the number of transverse frames and longitudinal stringers while reducing the height relative to traditional hull structures. By utilizing MHT, the area of unsupported spans of the hull shell is reduced, thus allowing for a decrease in hull laminate thickness while maintaining hull strength. The cockpit sole is framed transversely and suspended from the deck, thus isolating it structurally from the hull structure. This combination of hull and deck structure is capable of much higher deflections without failure compared to that of a traditional hull structure, thus increasing elastic energy absorption and decreasing shock loading.

Installing traditional insulation on marine structures is labor intensive and thus expensive, while insulation's long-term performance is typically reduced or greatly compromised by wet working conditions or mechanical damage. The purpose of this presentation is to highlight use of spray-on insulation materials and how their performance compares to traditional materials. Also to document the spray-on materials' better thermal performance, lower cost, lower weight and faster application than traditional materials.

Analytical expressions for the effective elastic properties of orthotropic, and laminated plates are presented for represented for representing swage panel subjected to extension and bending. A methodology is described for analyzing the swaged panels as effective, orthotropic flat plates. The equivalent rigidities of the laminated plating are established by matching the in-plane and flexural stiffness of the swage panel with those of the laminated plate. The required properties of the effective plating include the dependent Young’s modulii, shear modulus and Poisson’s ratios for each layer of a multi-layered elastic laminate. Three-ply and five-ply models are developed. This methodology allows for the use of well-known plate theory equations or assessing plate strength and stability. It also allows for the use of large-scale finite element modeling of the panels within conventional simulation packages such as those used for whole-ship structural modeling. The advantage in this analytical approach is to avoid the need for modeling the detailed, fine-scaled swage shell geometry in finite element analyses.

The United States Coast Guard is responsible for completing all of its statutory missions in U.S. waters surrounding Alaska. In the past, patrols in these waters have been limited to areas outside of the seasonal sea ice boundary, plus one or two icebreaker patrols per year. Recently, due to reduced sea ice areal coverage and the associated increases in commercial activity, demands for a Coast Guard presence in the Alaskan Arctic have increased significantly. In addition to ongoing efforts to increase the size of the icebreaker fleet, these demands have caused the U.S. Coast Guard to operate non-ice-strengthened cutters in areas where sea ice could be encountered, and to evaluate the capabilities of these cutters to operate in ice. This paper presents results of engineering studies completed over the past several years to evaluate the capabilities of current and future cutters for operations in ice and cold temperatures. These studies, which are also applicable to naval combatants, include: (1) definition of sea ice characteristics variations with season and geographic location; (2) evaluation of the ice-transiting capabilities of non-ice-strengthened hull structures; (3) analysis of potential increases in safe operating areas for different levels of ice strengthening; (4) evaluation of the capabilities of existing rudders, propellers, struts and shafting to withstand ice impacts; (5) assessment of possible cold temperature operating issues for deck equipment; and (6) analysis of the capabilities of HVAC, electrical and seawater systems to operate in cold air and water temperatures. Findings for each of these studies are discussed and results are presented. In addition, lessons learned from actual operations are included where appropriate. Finally, recommendations are offered for future class-specific engineering evaluations and operating considerations when non-ice-strengthened vessels are assigned to operating areas where sea-ice and cold temperatures may be encountered.

The two most important tasks of ice breaking ships are first to secure a sailing route by breaking the thick sea ice and second to sail efficiently herself for purposes of exploration and transportation in the polar seas. The resistance of ice breaking ships is a priority factor at the preliminary design stage; not only must their sailing efficiency be satisfied, but the design of the propulsion system will be directly affected. Therefore, the performance of ice-breaking ships must be accurately calculated and evaluated through the use of model tests in an ice model basin before construction starts. In this paper, a new procedure is developed, based on model tests, to estimate a ship’s ice resistance during continuous icebreaking in level ice. Some of the factors associated with crushing failures are systematically considered in order to correctly estimate her ice-breaking resistance, while the effects of the hull geometry, as reflected in the length, breadth, and draft of ships, are considered in calculating buoyancy and clearing resistance. Multiple regression analysis is calculated with each ice resistance component. This study is intended to contribute to the improvement of the techniques for ice resistance prediction with ice breaking ships.

Shipping in ice covered Polar waters is increasing and new ice classed ships are built to replace older ice strengthened fleet. Selection of suitable ice class for ships operation is an important but not simple task. The process of selecting an appropriate ice class is of high importance both from a safety as well as an economical perspective, but the selection process is still based on accumulated experience and traditions within the areas of existing operations. The increased exploitation of the Polar waters, both seasonal periods and geographical areas, as well as the introduction of new international design standards, reduces the relevancy of using existing experience as basis for the selection, and new methods and knowledge have to be developed. Based on the full scale measurements of ice loads during summer 2013-2014 in the Antarctica, the structural strength of the South African research vessel S.A. Agulhas II has been evaluated to assess the suitability of the chosen ice class of the vessel. The new polar code and especially the new Polar Operational Limit Assessment Risk Indexing System (POLARIS)is applied on this vessel to evaluate the suitable ice class. It is found the PC 3 is the most suitable ice class for ships navigating in harsh Antarctic ice conditions.

For maintenance of navigation during wintertime in Arctic seas, icebreakers create the wide channels in the fast ice cover or pack ice cover at water areas near to ports with intensive vessel traffic. Within such wide channels cargo ships and tankers can move in both directions independently without icebreaker pilotage among small ice floes. Because the cross-sectional dimension of the channel is restricted, the ships are forced to displace from the center and move on a close distance between their board and border of channel. The space between ship hull and borders is filled by small ice floes, and its concentration near the starboard and portside differs. The ice resistance on each board also differs. Therefore, side force and yawing moment arise that are able to cause the collision with the channel border. This paper contains the detailed problem definition and the main points of the mathematical model of vessel interaction with the channel border. As an example of model application possibilities, the simulation of loads on the hull of the vessel was performed. Outcomes of the investigation are dependent upon the side force and yawing moment on the distance from the channel border and ice conditions.

The U.S. shale gas boom inspired the marketing demand for a very large containment system (VLEC). Among various kinds of possible cargo containment systems (CCS) for VLEC, the Type-C independent tank is considered to be a reliable, robust design and is a competitive candidate. There are a number of design challenges to design and construct Type-C tanks suitable for VLEC. Thicker plate is generally used, and hence there is more significant tank shrinkage. In addition other factors to be considered includes sloshing, thermal stresses induced by large tank dimensions, and the interaction between tank and hull structure under low temperature conditions. Since the VLEC cargo tank concept design and material selection have been done, the possible maximum thickness of steel plate that may be adopted has been verified. The feasibility of Type-C cargo tank’s application in VLEC project has been researched and verified by various kinds of calculation and analysis, including IGC-based rule check and finite element analysis (FEA), low temperature shrinkage analysis, sloshing analysis, thermal stress analysis, etc. Construction cost and time schedule have also been investigated and compared among three kinds of CCS based on a certain yard case. Some useful conclusions have been presented for VLEC CCS selection.

The IACS Harmonized Common Structural Rules (CSR-H) for Bulk Carriers and Oil Tankers has been issued on 1st Jan 2014, and will enter into force on 1st July 2015 to supersede the current CSR version (CSR-BC or CSR-OT). The latest amendments to 01 Jan 2014 version of CSR-H give lots of significant modifications on fatigue assessment. The purpose of this study is to introduce the main changes for fatigue requirement in such amendments, and evaluate their rationality based on some detailed FE analysis for some key issues. Meanwhile, the impact on the structural design, especially on the scantlings, will be discussed as well as some proposal. Some typical bulk carriers and oil tankers are investigated.

This paper presents a method to optimize an oil tanker cargo hold’s structural scantlings based on stiffened panel ultimate limit states. Two different tanker models and their results are presented demonstrating this optimization procedure using models of varying mesh densities. The full ship finite element models are loaded with multiple load cases, design bending moments, external hydrostatic pressure, and internal tank pressure. The working stresses of a stiffened panel, which are used for the panel’s ultimate limit states assessment, are obtained by 3D finite element analysis. Each stiffened panel is then optimized using multi-objective genetic algorithms for its weight and safety. The optimization process is performed on two different versions of the same vessel: one with all stiffeners defined explicitly and one with internal stiffeners (allowing the stiffener layout to be changed during the optimization). The numerical results show that the proposed method is very useful to perform ultimate strength based ship structural optimization with multiple objectives, namely minimizing the structural weight and maximizing structural safety.

Ceramic compounds have been around for many years, but the research to find which compounds, what size, crystalline structure and density would perform to block “heat load” is the keys the selecting the correct compounds to use. “Blocking heat load from radiation or resisting the absorption and loading of heat when used over a hot surface” is determined by the aspects stated above. None of this could be determined from the ceramic catalogs of listed compounds stating referenced characteristics. To determine how a compound would react in a paint/coating form could only be realized by trial and error when the compound is mixed in a resin solution with other compounds to see the result. This process has taken 23 years and over 3600 compounds to find 12 compounds that will continue to work when wet and mixed with other materials. As to the corrosion encapsulation without the need for sandblasting, this was studied after finding that most all corrosion protection specifications require sandblast, primers and top coats which over time did not perform as theory had projected. Part of the reason is due to the time frame after the blast is performed before the paints are applied. By the time the paints are applied a flash rust or bloom has set up and the surface is now out of specification and the result is a failure of the system. Research was applied on how a corrosion coating could be made to first penetrate deep into the pores of metal or rust, then swell and encapsulate the pores and/or surface rust before it sets up to 6780 psi surface tensile strength. In this way, the surface rust is used as the profile needed to anchor the coating and add to the strength of the coated film.

In this paper, problems associated with a current method for triangle heating, which is used by an automated thermal forming system, are addressed, and an improved method for handling the problems is proposed. The existing algorithm may yield heating information, which is applicable only for a limited range of plates in terms of thickness and may cause undesirable deformation such as ‘over-bending’ and buckling on the boundary. Therefore, a lot of man-hours are required for the correction of the deformation, which would significantly delay the fabrication process. To solve these problems, new formulae covering an extended range of plates are proposed, and the effect of the initial curvature of a plate is considered in the computation of heating information to prevent unexpected deformation. It is shown that the proposed method can induce a desirable amount of deformation on a plate and improve the accuracy of the automated thermal forming system for forming a convex shape. Various examples used in the ship construction are taken to demonstrate the performance of the proposed method.

Weld shrinkage data models were developed for thin uniform and complex ship-panels to predict in-plane shrinkage. The complex features in the thin panels include cutouts, inserts, multiple thicknesses, and non-rectangular shaped panels. By analyzing the measured data, it was found that there was no clear indication that a cutout affected the overall panel in-plane shrinkage although it induced more out-of-plane distortion. It was observed that the inserts induced additional butt joint across-weld and along-weld shrinkage and did not affect the fillet-weld shrinkage. The weld shrinkage data models were embedded in Microsoft Excel spreadsheets for ease of use. The spreadsheets permit the user to input the panel design parameters including material type, plate thickness, stiffener shape, spacing, and length, and overall panel dimensions, as well as complex-panel features that include inserts, multiple plate thicknesses, and non-rectangular-shaped panels. The user can also provides fabrication details, such as the welding process, weld sizes, welding parameters, and the use of fixtures.

In this paper, structural integrity of ship structures is discussed using Finite Element analyses. Buckling behaviors of shell structural components are investigated taking into account geometric and material nonlinearities. Recommendations are made to Naval Architects based on tools developed throughout the research.