Papers, Authors & Abstracts

The SNAME Annual Meeting will feature the offical release of dozens of technical papers and over 50 hours of cutting-edge technical presentations. Prospective attendees can review the paper abstracts immediately upon their release.  Annual Meeting registrants have immediate access to the current draft of papers.  See the Schedule Page for information on paper presentations. 
Maintaining Marine Diesel Emissions Using Performance Monitoring
Herb Roeser (V), Trans Marine Propulsion Systems, Inc.
Dilip Kalyanker (M), Trans Marine Propulsion Systems, Inc

Ships are an integral part of modern commercial transport, leisure travel, and the military system. A diesel engine was used for the first time for the propulsion of a ship sometime in the 1910s and has been the choice for propulsion and power generation ever since. Since the first model used in ship propulsion, the diesel engine has come a long way, with several technological advances. A diesel engine has a particularly high thermal efficiency. Added to it, the higher energy density of the diesel fuel compared to gasoline fuel makes it inherently the most efficient internal combustion engine. The modern diesel engine also has a unique ability to work with a variety of fuels, like diesel, heavy fuel oil, biodiesel, vegetable oils, and several other crude oil distillates, which is very important considering the shortage of petroleum fuels that we face today.

In spite of being highly efficient and popular, and in spite of all the technological advances, the issue of exhaust gas emissions has plagued the diesel engine. This issue has gained a lot of importance since 1990s when IMO, EU, and the EPA came up with the Tier I exhaust gas emission norms for the existing engine in order to reduce the NOx and SOx. Harsher Tier II and Tier III norms were later announced for newer engines. Diesel fuels commonly used in marine engines are a form of residual fuel, also known as dregs or heavy fuel oil, and are essentially the by-products of the crude oil distillation process used to produce lighter petroleum fuels like marine distillate fuel and gasoline. They are cheaper than marine distillate fuels but are also high in nitrogen, sulfur and ash content. This greatly increases the NOx and SOx in the exhaust gas emission. Ship owners are trapped, on one hand, between the need to use residual fuels (due to cost of the large volume of fuel consumed) in order to keep the operation of their ships to a competitive level and, on the other hand, the need to satisfy the stringent pollution norms as established by the pollution control agencies worldwide.

Newer marine diesel engines are being designed to meet the Tier II and Tier III norms wherever applicable, but existing diesel engine owners are still operating their engines, with the danger of not meeting the applicable pollution norms worldwide. Here we make an effort to look at some of the measures that existing marine diesel engine owners can take to reduce emissions and achieve at least levels prescribed in Tier I. Proper maintenance and upkeep of the engine components can be effectively used to reduce the exhaust gas emissions.

We introduced a pilot program on diesel engine performance monitoring in North America about two years ago, and it has yielded quite satisfying results for several shipping companies. More and more ship owners are looking at the option of implementing this program on their ships.

Numerical Modeling of Dynamic Stability Events on a High Speed Catamaran
Sean Kery (M), CSC Advanced Marine Center
Michael Webster (M), Austal Ships
Janelle Prange (V), University of Virginia & CSC Advanced Marine Center

A dynamic stability event— not to be confused with ordinary or damaged transverse stability—is a sudden and seldom occurring event that can result from an unusual dynamic response in some combinations of speed, heading, ship motions phase and wave field. This paper defines several dynamic stability events and describes a process developed to investigate them. The process involves model tests, numerical analyses, and a high speed catamaran test vessel. The strengths and weaknesses of model testing are compared to numerical analyses, and the overall validity of the results is discussed.

Zero Emissions Vessels
John W. Boylston (LM) Naval Architect
Bret S. Smart (M) Student, Massachusetts Institute of Technology
John P. Wise (M) Naval Architect, Metal Shark Aluminum Boats

This paper proposes a LNG-fueled coastal RO/RO for the East Coast of the US trade to meet upcoming Emission Control Area (ECA) requirements. The exhaust system for this vessel is proposed to be a wet system so there is no airborne emission. The CO2 remaining in the exhaust system is removed in the exhaust stream, and remaining exhaust components are combined with cooling water to provide a cooling effluent that meets Environmental Protection Agency (EPA) requirements. The concept design is carried to the point of determining operating economics, and the environmental effect of operating such ships is assessed as compared to conventional truck traffic. It was found that each ship will reduce East Coast highway truck traffic by over 1900 trucks per week. Since there are no emissions from the ship, each ship will also bring environmental advantages. It appears the ship would be economically competitive with conventional truck transport: the cost for transporting a single 53’ trailer via ship is roughly $996, compared to $1245 via truck. Furthermore, the proposed three vessel shipping service could potentially remove nearly 300,000 vehicles from the road annually.

Operational Evaluation of Stern Boat Deployment Systems
R. Sheinberg1 (FL), C. Cleary1 (M), F. DeBord1 (M), W. Thomas1 (M), R. Bachman2 (M), J. St. John3 (M), S. Minnich2 (M)

Stern-ramp deployment of small boats is an essential feature of all new U.S. Coast Guard cutters. The first new cutter to enter service equipped with a stern-ramp is the USCGC BERTHOLF, the lead Maritime Security Cutter Large (WMSL). During the summer of 2009 a series of sea trials was completed aboard BERTHOLF to define safe operating conditions for stern launch and recovery, develop recommendations for system design improvements, and provide performance data for use during evaluation of future designs. This paper summarizes the results of the boat launch and recovery sea trials and provides recommendations for the design of future systems. Findings are compared to those given in a previous paper presented at the 2003 Annual Meeting (Sheinberg et al 2003) and revised design considerations are presented. These considerations include ramp geometry, limiting ship motions, small boat design features, and special systems such as well water flow management systems and boat capture mechanisms. Finally, the issue of predicting the performance of these systems using physical and numerical modeling techniques is revisited, design criteria are critically assessed, and the importance of operator training is discussed.

1. U.S. Coast Guard Surface Forces Logistics Center
2. Naval Surface Warfare Center Carderock Division
3. Science and Technology Corporation

Designing Effective Machinery Control and Alarm Systems in the Age of Unattended Engine Rooms
Stephen Kemp (M), Stephen G. Kemp Marine & Process Controls LLC
Matt Arcy, P.E. (V), Chevron Energy Technology Company

This paper examines the evolution of shipboard machinery control and alarm systems, from the steam ships of the mid-20th century, which had little or no automation, to the unattended engine rooms of today, with their distributed control systems and remote monitoring of machinery systems. The authors, who together have extensive experience in operations, maintenance, and automation design in the maritime and petrochemical industries, believe the rapid development of PC-based monitoring and control systems has led to cluttered displays, an overload of information to the operators, and unnecessary alarms which can mask deteriorating conditions in shipboard systems. In particular, the authors are disturbed by weak accountability standards and the lack of any requirement in modern regulations for an engineering or deck officer to respond to a machinery alarm by attending to it locally (i.e., physically going to the area of the alarm to examine the machinery space). This local acknowledgement feature was present on one of the first ACCU ships approved by ABS almost 40 years ago, although the rules at the time did not specifically address this issue. Regulations today require only that an alarm be acknowledged at the central control room (CCR) or engine control room (ECR), which may or may not be in or part of the machinery space. The authors believe that local acknowledgement of alarms is a fundamental component of good watchstanding, and is therefore critical to the effective design of machinery control and alarm systems.
The authors propose a system design which combines PC-based terminals with simple, highly visible alarm indication utilizing light board displays. Light boards were the forerunners of the PC for annunciation of alarms, and the authors believe these simple, rugged devices can be effectively employed to provide the ship’s officers and crew members with extremely fast and reliable indication of the condition of the ship and machinery plant. They focus the attention of the ship’s officers on the light boards rather than on the multiple screens and pages of alarms on the ship’s PC’s, which often dilute the urgency of alarms because there are often so many on the display.
Finally, the authors introduce the concept of a “clear alarm board” required for sailing. By separating the alarms into categories that are displayed on the light boards, the most critical of these alarms can be chained into permissives for starting the propulsion system, or be part of a pre-departure review process that addresses operation under “non-clear board conditions”. The authors also propose removing alarms from the system that are not truly alarms, but rather “events” that do not require acknowledgement, and suggest that better system design can eliminate many of these all together.
By requiring local acknowledgement of alarms with the re-introduction of the light boards the authors believe that ships will be more professionally operated, and will provide the ship’s officers with a more clearly defined and visible indication of the condition of the machinery spaces.

Prediction of underwater noise for environmental impacts: Evaluation of a commercial vessel and offshore structure
S. J. Lee (V), H. J. Kim (V), J. H. Lee (V), J. H. Kim (V) and J. S. Seo (V), Samsung Heavy Industries Co., Ltd

The study of the environmental impact of underwater noise has become increasingly visible. Recently, underwater noise regulation has become an international concern. Therefore, the mitigation of underwater noise emission in operation is an important factor in the design of environmentally friendly ship and offshore structures. As a ship building company, in order to meet the increasing demand for an eco-friendly vessel, Samsung Heavy Industries Co., Ltd. has developed a standard procedure to estimate underwater noise in the initial design phase. This procedure can be used both to design a low-noise vessel and also to evaluate environmental impacts. In this paper, the procedure employed to estimate underwater noise is presented with results from full-scale measurements.

Robert G. Allan, P. Eng. - Executive Chairman, Robert Allan Ltd.
Kenneth D. Harford, P. Eng. - President, Robert Allan Ltd.
Derek Noon - Manager of Engineering, Robert Allan Ltd.
Jody Bjerkeset, P.E. - Site Contract Engineer, Robert Allan Ltd.
Chief James Dalton - Battalion Chief; Marine Division, Fire Department of New York
Chief William Siegel - Chief (Retired); Marine Division Fire Department of New York

The "Three Forty-Three" is the first of two new fireboats of this design. The second vessel is due for completion later in the year. These major, fast response fireboats were designed to specifically address the fire-fighting and rescue needs of the greater New York harbor, including the New Jersey shore. This includes the capability within the vessel to respond to any chemical, biological, radiological, and nuclear (CBRN) incident.
The fireboats are designed for a response speed of 17.4 knots, with a low-wake, 12 knot cruising/patrol speed. The powering, seakeeping, and wake generation characteristics of the semi-displacement hull form were all verified in an extensive model-testing program. The resulting propulsion system is a unique, quadruple screw, controllable pitch propeller (CPP) configuration.
The paper focuses on the various initial studies performed to establish the basic design configuration, the model testing and performance verification process, the value engineering studies performed, the many unique design features of the fire-fighting and emergency response capability of these vessels, and the performance trials results. Finally, the challenges of managing a major shipbuilding project for a major civic Government Client such as FDNY concludes the paper.

LNG as a Vessel and General Transportation Fuel: Developing the Required Supply Infrastructure
Gary W. Van Tassel (M) Principal, VT Design, LLC and Manager, LNG Technical, Argent Marine Companies

LNG holds great promise as a transportation fuel making significant reductions in emissions and green house gases. The road to increased use of LNG as a heavy transportation fuel in the U.S. is the development of a coherent LNG supply infrastructure. The existing LNG import terminal infrastructure can be leveraged to implement a safe and reliable fuel supply infrastructure. This paper will discuss the transshipment of LNG, by an AT/B LNG carrier, from existing U.S. LNG import terminals, in a hub and spoke arrangement.

Implications of Performing Tugboat Stability Analysis with Fixed Trim Assumptions
W. J. Foster (M) JMS Naval Architects & Salvage Engineers
& T. B. Powell (M) JMS Naval Architects & Salvage Engineers

Tugboat and towboat stability analysis may be performed with either “fixed trim” or “free to trim” methodologies under the current Code of Federal Regulations (CFR). The “fixed trim” method allows the vessel’s draft to change with increasing heel angle, while maintaining constant trim until the trimming moment is zero. The “free to trim” method is representative of how the vessel will behave, allowing the vessel to trim until the trimming moment is zero, with no restrictions on draft or trim. The use of the fixed trim method originally simplified the calculations performed by naval architects and produced accurate results for traditional model bow tugboats that were predominant. However, as tug styles and computers have evolved, the methodology is no longer as relevant or necessary.

The paper quantifies what affect the fixed trim method has on the calculated righting energy at large angles of heel and determines when the method is no longer valid. The analysis looks at tugboats currently in operation representing a range of design characteristics and ages. The results show that the fixed trim method may provide a reasonably accurate righting arm curve for traditional model bow tugboats in some loading conditions. However, the fixed trim method can result in unrealistic and exaggerated righting arm curves for many foc’sle bow tugboat designs particularly in the intermediate and load line conditions. As older tugs are modified and new design trends evolve, it is important that naval architects understand the underlying reasoning behind the regulations that are applied to these vessels.

The issue has become particularly relevant as older Load Line tugs are being repowered, modernized and, in many cases, converted into modern articulated tug and barge (ATB) units. These older tugs were not originally designed to the current stability standards and it is often a challenge for these vessels to comply.

Prediction and Verification of the Maneuverability of Naval Surface Ships
F.H.H.A. Quadvlieg (M) Senior Project manager / Knowledge coördinator Manoeuvring - MARIN
E. Armaoğlu (V) Project manager - MARIN
R. Eggers (V) Project manager - MARIN
P. van Coevorden (V) Hydromechanical specialist – Material Department - Dutch Ministry of Defense / Royal Dutch Navy

The NATO Specialist Team for Seaway Mobility has progressed significantly in the development of new mission oriented maneuvering criteria in the format of a NATO STANAG. This work is finalized in July 2010, and the STANAG is now submitted for ratification to all NATO member countries. Navies can now include maneuverability requirements in their vessel specification more comprehensively and accurately. Obviously, this will have implications for the prospective ship designers and builders, who will be obliged to meet these requirements.
The objective of the paper is to create awareness that these criteria are approaching soon. Tools and methods are to be brought in the starting blocks to be able to assist in the design of the vessels in accordance with the criteria.
The paper explains the prediction & verification procedures of vessel compliance. First, the philosophy and approach of the criteria is explained and discussed. Discussing all criteria is a task too detailed for this paper, because there are up to 240 criteria, depending on missions and capabilities. A selected subset of criteria is discussed in this paper.
An example of the verification process is carried out for one ship: the naval combatant benchmark vessel 5415M. The reader will be guided through the steps of: selection of criteria, selection of tools and the verification itself. The contents of the steps will be different in each loop of the design spiral. This paper shows methods to predict and verify compliance with each requirement in both the conceptual and detailed design stage. In the conceptual design stage the verification is done by performing numerical simulations and in detailed design stage these simulations are augmented by a smart selection of scaled model tests.

Real Time Local Sea State Measurement using Wave Radar and Ship Motions
E. M. Thornhill (M) Defence R&D Canada – Atlantic
D. C. Stredulinsky (V) Defence R&D Canada – Atlantic

The Canadian Navy is exploring operator guidance systems designed to promote safer and more efficient operations in a seaway. These systems require accurate real time information on the local sea state. Recent sea trials with a wave radar system, which can produce directional wave spectra from the back scatter produced by conventional navigational radar, have generated good direction and frequency measurements, but wave height was found to be less reliable. However, by combining the wave radar measurements with ship motions, these wave height measurements are greatly improved. This paper presents some background of at-sea wave measurement, a description of the combined wave radar / ship motions procedure, and the results from several sea trials.

Boosting Ship Efficiency
Oskar Levander (V), Wärtsilä Ship Power Technology

Ship efficiency has become an increasingly important subject for ship designers and owners. Both the predicted high cost of fuel in the future and the need to reduce emissions is driving this strive for improved efficiency.
IMO is also seeking measures to reduce the CO2 emissions from ships, and their proposed Energy Efficiency Design Index (EEDI) aims at ensuring that future vessels will be more efficient. However, the index is a little bit controversial and all people do not think that the evaluation method will achieve the good intention of the regulation in the best possible way. The currently proposed formula is more affected by the ship speed than the actual efficiency improvement of the ship technology. There is also a danger that the index might cause a modal shift away from sea transport to land based alternatives, which would not aid in the reduction of greenhouse emissions at all. The proposed EEDI calculation method should be altered in order to avoid the current shortcomings and be more affective in stimulating the introduction of more efficient ships.
Two ship concepts, a large RoRo vessel and a Cruise ferry, have been developed to highlight different technologies that can be used to improve efficiency and to create a picture of what can be achieved by applying just a few simple design features. The design work shows that the power demand can be reduced significantly with already basic naval architecture methods. Optimisation of main dimensions for life cycle cost rather than building cost alone can give large savings. Also new propulsion concepts, such as triple shaft lines or Wing thrusters yield clear propulsion power savings. Other measures to reduce fuel consumption, such as waste heat recovery and wind power also show clear gains.
Vessels operating inside future emission control areas (ECA) will face new requirements regarding emission limits. The study shows a clear advantage of using LNG as fuel. Both operating costs and emissions can be reduced. Also abatement technologies for reducing sulfur emissions is promising compared to the alternative of using distillate fuels.
The development work shows that large efficiency improvements can be gained with novel ship designs using today’s state of the art technology.

Identification of Critical Sea States for Sloshing Model Tests
Booki Kim (M), American Bureau of Shipping (ABS)
Min-Cheol Ryu (V), Jun-Hyung Jung (V), Daewoo Shipbuilding and Marine Engineering (DSME) Co., Ltd.
Yungsup Shin (M), American Bureau of Shipping (ABS)

This paper presents a methodology for identifying a set of irregular sea states for sloshing model test conditions that are most likely to produce large sloshing pressures on tank walls. To identify the sea states, first the sloshing pseudo-response amplitude operator (RAO) is defined based on the total sloshing wave energy that is the sum of kinetic and potential energies on the free surface. The mathematical model is formulated in the frequency domain within the regime of potential flow theory. A concept of sloshing intensity is then introduced to define the sloshing severity in an irregular sea state based on the area under the sloshing wave energy response spectrum curve. The tank is expected to induce violent fluid motions for high sloshing intensity values, and, as a result, its walls experience large sloshing impact pressures. The validity of the proposed methodology is investigated by comparing the results of the numerical analysis to those of the model test for the cargo tank of a floating liquefied natural gas terminal. Favorable results in identifying critical sea states for the sloshing test conditions are obtained for several filling levels. The proposed methodology can be utilized as a pre-screening procedure for selecting relevant sea states at the initial phase of the sloshing model test and for use in the selection of sloshing flow simulation conditions

Model for Environmental Assessment of Container Ship Transport
Hans Otto Holmegaard Kristensen (M), Senior researcher, TheTechnical University of Denmark (DTU)

A generic computer model for systematic investigations of container ship designs is described in this paper. The primary statistical data on container ships used for the model development are also presented. The model can be used to calculate exhaust gas emissions from container ships, including emissions of carbon dioxide (CO2). A calculation procedure to estimate the newly designated Energy Efficiency Design Index (EEDI), which is under development at the International Maritime Organisation (IMO), is included in the model. Different ship design parameters have been varied to see the influence of these parameters on the EEDI. It is found possible to reduce EEDI by roughly 20 % without reducing ship speed, but only by changing some of the design parameters, such as reducing the sea margin by using a derated main engine, increasing the length of the ship by 5 %, and reducing steel weight by 3 % via steel weight optimization.