The U.S. Navy Surface Fleet currently possesses no minelaying capability, instead relying on air and submarine assets. In the context of growing challenges to U.S. naval supremacy, this represents a significant strategic capability gap. Due to the asymmetric nature of mine warfare, the only feasible solution to close that gap must be cost-effective. This study develops a concept design for the conversion of a commercially available working boat to a minelayer in the form of an affordable, modular and rapidly scalable “bolt-on” system with flexible implementation to a variety of parent hulls and payload capacities.

The U.S. 2021 National Defense Authorization Act (NDAA) requires one main propulsion system and one electrical generation and distribution system of the Navy’s Large Unmanned Surface Vessel to be qualified by a Senior Technical Authority. To address this, related Navy offices and the American Bureau of Shipping (ABS) developed a process for a Navy-specific qualification for USV program equipment and systems to support verification of both design and reliability. This paper presented includes detailed discussions of the process increments (Product Design Assessment, Technology Readiness, Reliability Qualification) and a review of the full process using an example.

After more than one hundred years the Titanic is still probably the most remembered ship in the world. This paper briefly discusses the history of the Titanic from why the White Star Line decided to build the Olympic class ships through the recently signed treaty protecting the ship. It is shown that many of the design features of the ship were far ahead of the rest of the industry but that some compromises were against the naval architect’s desires. A number of myths concerning the ship are dispelled. The circumstances leading up to the collision with the iceberg and the sinking of the ship are examined followed by an analysis of the sinking; the discovery of the ship; and finally after almost thirty-five years, a treaty to protect the ship.

With the impact of increased fire resistance requirements that NAVSEA is invoking on ship programs, and the lack of structural doors (i.e., watertight) that are also fire resistant, the industry can benefit from having a compliant option for structural doors that maintains the required internal shipboard fire zone boundaries using only one structural door. Currently using either legacy Navy standard watertight single doors or the new standardized family of watertight single doors tested for pressure and shock qualification during the prior NSRP project, would require installation of two doors in close proximity to one another at fire zone boundaries. One that serves as a fire barrier and the other serving to maintain watertight integrity, or some other mitigating design. A fire resistant watertight door design will reduce the area and volume penalty to ship designs compared to alternate methods and will reduce the ship cost due to having fewer doors to purchase and install. Upon incorporation in a revised Navy standard drawing, these drawings are expected to be invoked on current and future shipbuilding contracts, which will provide a strong basis for widespread implementation after the project is completed.

This paper analyzes weather data recorded by typical oceanographic buoys using data analytics and regression techniques. Time series data over a period of more than four decades (1976 – 2020) are reviewed and profiled. A set of key variables including seasonality, wind speed, wind direction, wave period, wave direction, etc., are screened from the buoy measurements to build a predictive model based on multiple linear regression for significant wave height prediction. A sensitivity analysis is then conducted for the available weather window corresponding to specified threshold operational limits of the significant wave height. Key insights are presented along with suggestions for future work to assist marine operators in planning and derisking offshore operations. Utilizing the algorithms and workflows presented in this paper, a user can increase confidence in weather window prediction, and develop safer, efficient offshore operation plans.

The United States Army operates several classes of landing craft, which provide combatant commanders with waterborne maneuver capabilities essential for accomplishing a range of critical missions unique to the Army. These missions involve transport of personnel, cargo, and equipment from advanced bases and large sealift ships to ports, inland riverine regions, as well as remote undeveloped coastlines and beaches. Recognizing the significant roles these vessels play and will continue to play in achieving Army objectives, Army leadership allocated funding to design and build a new class of high performance landing craft: Maneuver Support Vessel (Light) (MSV(L)). The primary mission of MSV(L) is to conduct movement and maneuver of combat-configured Brigade Combat Team force elements such as one M1A2 main battle tank, or two Stryker vehicles, or four Joint Light Tactical Vehicles, each with its crew. MSV(L) will have beaching capability and be able to operate at speeds significantly in excess of any current Army landing craft. The Army Watercraft Systems organization was tasked with overseeing development of requirements and specifications, source selection and acquisition, along with contract, finance, and engineering management of the MSV(L) Program. A contract to develop the detailed design and build a series of vessels was awarded in September 2017. Launch of the initial vessel is planned during the fourth quarter of 2021.

Ocean towing in general, and non-routine tows in particular, present unique technical challenges to towing vessel owners/operators, salvors, the offshore oil/gas and wind industries, and others. When such tows “go wrong”, the harm to human life, property and/or the environment can be significant. The authors have drawn from their work on the Towing Safety Advisory Committee’s investigation of the grounding of the MODU Kulluk to present methods and considerations in analyzing ocean towing evolutions, both “routine” and “non-routine”. (TASK 14-01) The methods and considerations presented should be employed in advance of a towing evolution, but can be used in accident reconstruction and forensic analysis when an evolution has failed. The methods presented are iterative, and consider 2 x 6 degree freedom of motion (of the towing vessel(s) and towed vessel respectively) and characteristics of the towline, and facilitate determination of: Worst Case Conditions. Extreme Towline Tension (ETT) as a function of sea state and speed. Limits of the Tow (Go-No Go Criteria). Recommended Catenary Length as a function of sea state and speed. Size and Selection of the Towing Vessel and Gear, including: Required Bollard Pull. Required Strength, Characteristics and Condition of the Towline. Limits and Set Points of the Towing Winch, Automatic or Manual. Required Strength and Characteristics of the Synthetic Emergency Towline and its methods of deployment and connection. Working Load Limit (WLL) of the Shackles, Delta Plate and Attachment Points. Required Strength and Characteristics of Bridles, Pendant and Surge Gear/Shock Lines. The authors further explore the implications of single point failure modes, redundancy in gear and towing vessel(s), high cycle fatigue, and strain monitoring.

The Marine Forensics Committee is twenty-five years old and has had a number of investigations of ship wrecks and losses to better understand the causes of maritime accidents using ROV’s. AUV’s, advancements in underwater electronics, flooding and sinking simulations as well as the development of procedures for a casualty investigation. Some of the highlights from the twenty-five years of research and investigation of historical ship losses will be summarized.

This paper presents the concept and design of a tanker powered by, and carrying, liquid hydrogen (LH2). Beyond the realization of a complete reduction in carbon emissions, the concept is closely related to the authors’ proposal for a rethinking of ship operation with a substitution of Just-in-Time (JIT) by Warehouse-in-Transit (WIT). Ways to fund a LH2 tanker is also reviewed and suggested.

In May of 2020 a container ship sailing along the eastern coast of Australia encountered a storm and lost a number of containers. The loss of containers was not unusual, about 1400 containers are lost each year on average. What was unusual was the large number of containers on this one ship. Coincidentally, MARIN releasted a report in September 2020 investigating similar losses of large number of containers from container ships going to northern Europe. Then, between October 2020 and February 2021, seven ships on a northern Pacific route from China to the USA loss between 3,000 and 4,000 containers and had a large number of container stacks roll over. This paper is a independent generic assessment of a marine forensic investigation taking a systems engineering approach to look at the broad spectrum of possible causes of container stacks rolling over and lossing containers. The paper discusses weather effects on the stability and motions of the container ships and the securing of the cargo containers. The paper goes into detail about the underlying issue of the container stacks and their heights such that at decreasingly smaller angles of heel or rll, the line of action of the weight of the higher containers passes outside the base of the stack thereby causing a overturning moment on the corners of the containers.

After almost a century the US Navy has reintroduced tumblehome into the design of naval combatants. This paper discusses some of the reasons tumblehome was originally designed into ships and why it served it owners well for many centuries. The transition from sail to steam power a little over a century ago led to a variety of problems with the combatant ships designed with tumblehome where the lack of damage stability caused a major loss of life as these ships sank so quickly. During World War I ships designed with tumblehome fell out of favor and some of the ships were actually modified to remove the tumblehome from the design. These changes in the design of tumblehome ships are discussed in this paper.

In this paper, we discuss partition acoustic performance in the marine environment. We give an overview of relevant standards, typical approaches to measurement, and calculation methodologies. A discussion of lab-tested partition performance and in situ measured values is provided in this paper, with commentary on typical flanking paths. Applicability of the Rw criteria to the marine industry and practical aspects of performing these tests in a marine environment are also discussed. These new requirements may help improve the life and safety of marine workers. However, to be effective many details of partition design, installation, and testing must be properly executed.

This paper provides the results of model tests in ice to evaluate the performance of the USCG Mackinaw Icebreaker which equipped with two podded propulsors and compares with the data obtained from the full-scale ice trials. The objective of this collaborative model test program between the NRC and USCG was to understand the capability and limitation of the model tests with podded vessels in ice. As a result, the model tests showed a good agreement with attainable speeds at selected power levels but an overestimation of the ice resistance by an average of 7 % (from -10 % to 25%). Further discussion of podded icebreaker performance including turning circle tests in ice is provided and future work is proposed. This paper also provides a discussion of two different flexural strength test methods, which are simple beam and cantilever beam tests.

As in automotive, the use of lithium-ion batteries onboard vessels is increasing rapidly. Whether in hybrid or all-electric mode, the technology makes possible significant to even game-changing reductions in fuel consumption and emissions. However, as their use increases, so too will negative impacts both before installation on the ship and after removal. At the front end, this paper will explore the abundance of the raw materials, their mining and related ecological and societal concerns. At the back end, reuse markets and recycling will be covered including cost drivers and emissions. Recycling will examine the methods and their efficiencies, module disassembly problems and neutralization of remaining charge. The paper will close with environmental risks in disposal.

At the center of litigation involving vessel collisions and allisions is the history of the movement and interaction of the vessel with its surroundings. Forensic analysis of an incident, and sometimes litigation, seeks to resolve the causes and timing of the vessel movements. Simulation and animation are tools to analyze the vessel movements, and simulation is a tool to analyze the actions and possible alternative actions that could have been taken by the operators. Animations can serve to present reconstruction of the accident in a visual form. Animation is also a tool used to explain complex events and devices to a less technically sophisticated audience. This paper provides examples of simulations and animations that enhance understanding of marine accidents and describes the characteristics that may make these tools suitable for use in litigation.

Iron has a property called "auto-ignition". For cutting, that property is the mechanism for the oxy-fuel cutting process. When iron is heated to the auto-ignition temperature 1,315 degrees Celsius (2,399 degrees Fahrenheit), then the iron will ignite, and "burn" in normal atmosphere, and at lower temperature of 900 degrees Celsius, or less, in the presence of pure oxygen. The method of heating is irrelevant, because the chemical reaction with the oxygen is the primary mechanism of the cutting. For standard oxy-fuel cutting, the metal is cut almost entirely by that exothermic chemical action. The surface of the iron is melted by the heat of the oxidation reaction. The force of the oxygen stream quickly moves the oxide which is produced away from the cut-zone. This ensures a clean liquid iron surface on which the oxygen stream impinges. The heat to keep the cut going - once it has started - is provided partly by the burning oxygen plus fuel mixture, and partly by the heat from the chemical reaction of the heated iron with the oxygen. The new cutting process uses induction heating of the iron/steel instead of burning oxygen plus fuel. Oxidation of the iron is still the primary heat source to melt the iron, and the oxygen stream force removes the oxidized iron, so the oxygen can continue to reach the melted iron. Induction is many times as efficient for heating the iron to the auto-ignition temperature. So, a cutting system consisting of the induction heating and then followed by a stream of oxygen can cut many times faster than oxy-fuel. Also, a combination of induction heating and a plasma torch can heat the metal even faster. So the hybrid induction-plasma process has also been invented. The plasma, while very hot and precise, is not an efficient heating mechanism. But, by combining the induction with plasma, the high quality of a plasma cut is achieved, but the cutting speed can be 10X, or more, faster than using the plasma alone.

While transiting off the Southeastern Connecticut coast in 2019, F/V Emma & Maria experienced a knock down incident. This paper investigates the causal factors of this event, specifically focusing on stability challenges common to the New England commercial fishing fleet. After identifying contributing factors to the incident, an incline test was conducted to determine the center of gravity of the recently modified vessel. A stability, seakeeping and operability analysis, across a range of operational and worst-case conditions, is presented to determine the limitations of the vessel. To improve vessel operability, the addition of concrete ballast in the aft bilge is proposed, resulting in an improvement in both vessel stability and seaworthiness. Possible improvements to current fishing vessel regulations are also suggested to improve the safety of the fleet.

Gaseous fuels have been the subject of intensifying interest from the marine industry over the past decade. Spurred by rapidly changing economic and political landscapes, vessel owners and operators are driven to find new ways to balance operating costs with environmental impact. As we adopt new technologies toward this goal, our knowledge base on gaseous fuels has been dominated by considerations relevant only to LNG. Advances in prime mover technology and changes in domestic energy production have made Propane a viable fuel option for a much broader range of vessel sizes and power outputs. To help level the field, this paper presents a comparison between LNG and Propane as shipboard fuels.

The US Navy is working to decentralize strike capability from fewer high value assets onto numerous and more affordable small platforms. An advancement of the feasibility of Navy’s distributed lethality concept, this study examined the conversion of Freedom Class Littoral Combat Ships to strike-capable platforms by replacing existing helicopter aviation facilities with a variety of missile launching systems and enabling sensors. The study produced and analyzed a tradespace of 384 variants with different vertical launching system (VLS) configurations, missile loadouts, and bolt-on weapon systems to ultimately choose an optimal combination of high performance and low cost.

The purpose of this paper is to discuss and document the evolution of the SOLAS subdivision and damage stability regulations, with a primary focus on recent developments to improve the survivability level of passenger ships after the SOLAS 2009 probabilistic subdivision and damage stability regulations were adopted on 20 May 2005 and subsequently entered into force on 1 January 2009. SOLAS international regulations represent a consensus standard and during their development there are frequently details that are not well documented. This paper is intended to provide that documentation and explain the recent progression of this sometimes convoluted development work.