Proceedings of the First Chesapeake Power Boat Symposium (summary)

The First Chesapeake Power Boat Symposium

March 7-8, 2008,

Saint Johns College, Annapolis Maryland USA

Performance Test Protocol

For Small Power Boats

Richard Akers (

M, SNAME

),

Small Craft Engineering, L L C

Clifford Goudey (

M, SNAME

), mit

Sea Grant College Program

T H E F I R S T C H E S A P E A K E P O W E R BOAT SYMPOSIUM

A N N A P O L I S , M A R Y L A N D , M A R C H 2008

U.S. Flag Group Owned Superyachts; A New Market for Designers, Shipyards and

Ship Managers

I

The opinions expressed in Ihis paper are those of the authors and do not necessarily reflect the opinions or official policy of Ihe Coast Guard or the Department of Homeland Security.

ABSTRACT

The market for superyachts has been growing at rates above 15% for several years (Beckett, 2007) and has represented a significant large powerboat market. One growth area in this market is vessels designed for group ownership, because as the individual cost o f ownership decreases, people w i t h less wealth are brought into the market. Since wealth follows a power cui-ve, a five f o l d decrease in ownership cost represents far more than a five f o l d increase in potential owners. However, group ownership requires significant changes in the paradigm o f use, design and management, including significantly more use i n U.S. waters, meaning U.S. flagging and inspection

becomes more advantageous (in part due to reduction in tax benefits o f offshore flagging). Therefore group-owned U.S. flag superyachts potentially represent an opportunity for designers, management companies and builders, but have significant regulatoiy constraints on design and operation that have to be considered.

NOTATION

M C A Maritime Coastguard Agency

IC GRT International Convention Gross Register Tonnage

OECD Organization for Economic Co-operation and Development

RePowering for Fuel Economy and Performance

-Methods for Engine and Propeller Selection

Frank W. DeBord P E , Member

A B S T R A C T

In the past several years, higher fuel prices combined vilh availability of modern, light-weight diesel engines has made diesel re-powering of older gasoline boats increasingly attractive. However, the differences in performance characteristics behveen diesel and gasoline engines, combined with the relatively limited knowledge of most boatyards and engine distributors with respect to performance prediction, can make the selection of engines and appropriate propellers difficult at best. Using an actual

example of re-powering a 1977 Bertram 33 Convertible, this paper discusses a range of performance prediction methods for engine and propeller selection. These methods range in complexity from simple spreadsheet calculations based on known speed versus RPM with the "old" engines, to a variety of rigorous calculations based on empirical and computational methods. These methods M'ould be suitable for a variety of situations ranging from simple calculations by an owner completing a preliminary cost

trade-off, to detailed engineering calculations more suited for a large, expensive project where performance must be accurately predicted. Results of each method are compared to actual trials data and

recommendations are offered for application of the prediction methods to projects with vaiying complexity and objectives. In addition, practical and engineering issues that must be addressed when completing a re-powering are discussed.

QUADRAPOD

A i r - A s s i s t C a t a m a r a n

.^m 3o T H E F I R S T C H E S A P E A K E P O W E R BOAT SYMPOSIUM

lif A N N A P O L I S , M A R Y L A N D , M A R C H 2008

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QUADRAPOD

Air-Assist Catamaran

Andrew P. Dize, Baltimore, Maryland ABSTRACT

QUADRAPOD is an air-assist catamaran liull form developed to further advance the use o f surface effect ship (SES) technology. The primary advantages presented by the Q U A D R A P O D technology include a significant reduction in propulsion power levels and fuel consumption to achieve a given design speed, and a low-wake signature to reduce wave energy to levels lower than a conventional semi-displacement catamaran hull form. The QUADRAPOD technology is able to achieve these benefits due to the unique hull geometiy which incorporates hydrodynamic l i f t from conventional shaped planning hulls and air cavities to provide additional h f t which results in reduced wetted surface resistance. The air cavities are unique in that no flexible skirts are required to maintain cushion pressure. In addition to the hull geometiy elimination o f high-maintenance flexible skirts, the hull design also allows for the use o f conventional propellers, water jet propulsors, or surface drive units with no air ingestion interface issues. The Q U A D R A P O D air-assist catamaran hull form is a US and internationally patent-pending and trademarked technology that is currently being developed for use in commercial and militaiy vehicle/passenger ferry applications. Size applications have been studied for vessels up to 650 feet in length.

INTRODUCTION

The Q U A D R A P O D (QP) technology is a hybrid surface effect ship (HY-SES). ft incorporates the resistance reducing features o f an air cavity ship (ACS) as well as the high-performance capabilities found in a surface effect ship (SES) combined into a conventional catamaran platform. The QP design combines pneumatic lift (approximately along 1/3 of length o f each catamaran hull) features o f an SES with the hydrodynamic lift (approximately 2/3'''''s o f length) features o f a high-speed planning boat. It is the incorporation o f hydrodynamic planning surfaces both forward and aft o f the air cavity that provides the QP hull form with a unique ability to maintain the vessel on air cushion in many differing sea states, without the use o f high maintenance flexible skirts.

These unique hull features allow the QP technology to be integrated with any number o f propulsors systems without any loss in propulsors efficiency due to air/water interaction typically found in ACS/SES designs.

Figure 1 - QUADRAPOD Hull Form

In that regard, the QP hull form ideally lends itself for use on larger vessels in the reduction o f powering and fuel consumption or an increase in speed. The speed versus fuel consumption trade-off decision becomes an operational one for the owner depending on the payload and operational requirements o f the vessel. The QP design provides the vessel owner with flexibility to decide whether speed at the sake o f fuel consumption or higher cargo capacity at a lower nominal speed (but always higher than conventional ship platforms) is desired.

The QP hull form has been incorporated onto a catamaran platform for the following reasons:

a. A catamaran platform provides a large working deck which allows for multiple vessel

C n n T B S L i t i a P i i r * r i i T i a

U S C G - NIOSH C O Update:

• Modeling of C O Intrusions on Express

Cruisers

• Evaluation of Indmar Catalytic Technology for

Propulsion Engines

Alberto Garcia, M.S.

James S. Bennett, Ph.D.

Kevin H. Dunn, M.S., CIH

Scott Earnest, Ph.D., CSP, PE

Ronald M. Hall, M.S., CIH

David A. Marlow

T H E F I R S T C H E S A P E A K E P O W E R B O A T SYMPOSIUM

'^K '• ) ) '§ A N N A P O L I S , M A R Y L A N D , M A R C H 2008

A Parametric Study of Dynaplane-Type Planing Motorboats

Eugene P. Clement, David Taylor Model Basin, (Retired)

John G. Hoyt U I , Hydroinechanics Department, David Taylor Model Basin, Naval Surface Warfare

Center, Carderock Division West Bethesda, Maryland, USA

ABSTRACT

Conventional planing motorboats, when running relatively fast, are supported mainly by dynamic l i f t . However, these boats are not configured so that the dynamic l i f t is produced efficiently. Therefore they have unnecessarily high drag. The hull drag o f planing motorboats can be approximately halved by incorporating the features that produce dynamic l i f t effectively. The required features are longitudinal camber cui-vature o f the planing area, appropriate size o f the planing area for the design speed and weight, operation at optimum angle o f attack, and relatively high aspect ratio o f the planing area. A planing motorboat configuration that incorporates those

features, the Dynaplane, has been developed, and its superior performance has been validated by the testing o f models and prototype boats.

Calculations o f t h e resistance o f Dynaplane-type boats for a wide range o f values o f the significant design parameters have now been made. The calculations show that only the single factor o f deadrise angle significantly affects Dynaplane resistance at planing speeds. Accordingly it has been possible to give a method f o r calculating planing-speed resistance of Dynaplane type boats, quickly and easily, for wide ranges of^ values o f deadrise angle, weight, size, and speed.

CARDEROCK DIVISION _NSWCCD

T H E F I R S T C H E S A P E A K E POWER

BOAT SYMPOSIUM

A Parametric Study of

Dynaplane-Type Planing

Motorboats

E u g e n e P. C l e m e n t a n d J o h n G - H o y t III

Hydromechanics Department, David Taylor Model Basin,

Naval Surface Warfare Center, Carderock Division

West Bethesda, Maryland, USA (Retired)

Hydromechanics Department, David Taylor Model Basin,

Naval Surface Warfare Center, Carderock Division

T H E F I R S T C H E S A P E A K E P O W E R B O A T SYMPOSIUM

Stray Current Electrolytic Corrosion: An Unrecognized Enemy®

Principal, Alan Ross Hugenot, Inc.,Naval Architects & Marine Surveyors, San Francisco, California

Chairman, Panel on Motor Yachts and Service Craft, SNAME Small Craft Technical and Research Committee

HEAVILY CORRODED ALUMINUM HULL IS TYPICAL OF RAPID ION LOSS DUE TO AC STRAY CURRENT CORROSION IN HOT MARINAS (Photo January 18, 2008, at San Francisco Boat Works).

ABSTRACT

P R E A M B L E : This paper examines the state of the art regarding Electrolytic Corrosion which is often mis-named as electrolysis. This corrosion of underwater metals is understood to be caused by stray currents passing through the water surrounding a vessel regardless of source. Such current flow causes corrosion (ion loss) of any immersed metals which happen to serve as the grounding conductor for any stray electrical currents.

Normally, with Direct Current (DC) stray currents the ion

loss at the metallic receptor (anode) is continuous, but because the majority of DC stray currents are of galvanic origin they occur at extremely low amperages (measured in milli-amps). Consequently, cumulative ion loss is slow and a long time passes before deterioration may be noticeable. To protect underwater metals against galvanic DC corrosion, cathodic protection techniques utilizing sacrificial zinc anodes were developed during the first half of the 20"* centuiy, at a time when nearly all small boats ehher had no onboard circuitry or only had 12 volt DC electrical systems.

,,vltR Bo

' T H E F I R S T C H E S A P E A K E P O W E R B O A T S Y M P O S I I I I M

ANNAPOLIS, M A R Y L A N D . M A R C H 2Ó08

P R O T O T Y P E O F A S M A L L m c H - E r FICTENCY CRUISING MOTOR Y A C H T DESIGN

Eric Jolley - Bieker Boats, Seattle, USA

T H E F I R S T C H E S A P E A K E P O W E R B O A T SYMPOSIUM

A N N A P O L I S , M A R Y L A N D , M A R C H 2008

New Varieties of Fast Air-Assisted Boats

Konstantin Matveev, Washington State University, Pullman, WA, USA

ABSTRACT

Marine vehicles intended for ultra-Iiigh-speed applications can beneficially use the air for drag reduction and l i f t augmentation. New types o f air-assisted marine craft include air-lubricated boats, aerodynamically supported multi-hulls, and ram craft with jet-induced l i f t . This paper reviews the current state o f these technologies, full-scale specifications o f some existing boats, experimental data, relevant mathematical theories, and future research directions.

INTRODUCTION

The air-assisted boats can achieve veiy high speeds (from 60 to above 100 knots) in safer and more economical manner than traditional fast boats. The complete transition to aerodynamic support in this speed range is not practical for boats with reasonable weight density. A combination o f aerostatic, aerodynamic, and hydrodynamic l i f t can be realized on such craft to achieve high performance.

Three novel types o f fast air-assisted boats, comprising the author's cuiTent research topics, are schematically illustrated i n Figure 1. The first concept includes a family o f fast air-lubricated boats with macroscopic air cavities on the hull bottom (in contrast to bubbly fiows). This technology is known as A i r Cavity Ship (ACS). The so-called artificial cavitafion or air venfilation o f the bottom o f a modified planing hull helps increase speed by about 20% at the same power level as for a non-ventilated boat. Besides the resistance advantage, ACS demonstrates some improvement in seaworthiness, which is an important operational factor for fast sea-going marine vehicles.

The second kind o f air-assisted craft is a vehicle with hybrid support comprising hydrodynamic l i f t o f trimaran planing hulls and aerodynamic l i f t o f a wing-shaped platform. While a demonstrated lift-drag ratio o f Aerodynamically Supported Trimaran (AST) models is

similar to that o f high-performance planing boats, the dynamic instability pertinent to planing hulls at veiy high speeds is effectively suppressed on AST. This results in doubling the speeds achievable in safe manner at the same payload characteristics.

P A R V

Figure I - Concept schematics o f A i r Cavity Ship (ACS), Aerodynamically Supported Trimaran (AST), and Power

Augmented Ram Vehicle (PARV).

The third technology is based on the combination o f the air-jet-induced lift, aerodynamic support due to fonvard motion, and hydrodynamic l i f t produced by multi-step planing hulls. Power Augmented Ram Vehicle ( P A R V ) o f this kind is an ultra-fast and truly amphibious craft with maximum speeds well above 100 knots at several hundred ton displacement. PARV can operate at lower thrust-to-weight ratio (around 0.2) and higher payload-to-thrust-to-weight ratio (around 0.5) than competing air-supported amphibious transports.

Characteristics o f three types o f air-assisted vehicles are summarized i n Table I , where some properties are

2 0 0 8 SNAME Chesapeake Power Boat S y m p o s i u m

D e s i g n & A n a l y s i s of integrated P r o p u l s i o n S y s t e m s for H i g h

-S p e e d C r a f t

Brant R. Savander, Ph.D., P.E.

Maritime Researcli Associates

Ryan J. Kamphuis

MFU Detroit Diesel

Cornel Thill, Dr.-Ing.

Maritime Research Institute of the Netherlands

Kevin D. Herman

Michigan Wheel Corporation

Scott Woodruff

MTU Detroit Diesel

The work documented herein has resulted from a collaborative research program funded by MTU Detroit Diesel In the high speed craft area with an emphasis on design and analysis of open shaft, strut, propeller, and rudder systems for recre-ational applications. The program combined both numerical and experimental hydro-dynamic analyses throughout the research process. The two primary areas of this effort were associated with planing hull and propulsor hydrodynamics. Numerical results from various ideal flow theories for both planing hulls and cavltating propel-lers are compared with model test results conducted at the Maritime Research Insti-tute o f t h e Netherlands (MARIN). The model testing program Included the traditional experimental matrix of EHP, appended HHP, SHP, and nominal wake survey all In the absence of any Influence of cavitation. Cavitation number effects were Included through a series of experiments In both a cavitation tunnel and depressurized towing tank at MARIN. Both the numerical and experimental findings are compared with full scale sea trial data from the subject craft, a 70 foot planing hull with a top speed of 50 knots. Research program challenges and areas for further development are pre-sented and discussed.

Introduction

The recreational, commercial, and military Industries have and continue to demand marine vehicles that are larger and faster than historical predecessors to support the expanding needs of high speed marine transport. Each Industry segment would like to carry more payload, over greater distances, at higher speeds. Marine die-sel engine and gas turbine manufacturers have developed many high power density products to meet these expanding markets. In all cases, a significant challenge Is always management of this power to drive the ves-sel.

Many successful projects In all industries have been documented. Conversely, the challenges are also apparent. The military seallft community Is confronted with the conflicting constraints of the need for a small transom from a hull resistance perspective. However, the same vessel requires sufficient transom beam to accommo-date the number of waterjets needed to absorb the large amount of available power. The commercial sector limitations are similar In nature to that of military Industry.

The First Chesapeal^e Power Boat Symposium

March 7-8, 2008,

Saint Johns College, Annapolis Maryland USA

Regarding Small Craft

Seakeeping

Dean Schleicher, P.E.

Donald L. Blount and Associates, Inc.

Regarding Statistical

{i

^iLm^

Relationships for Vertica \ ^ ^ ^ ^ /

Accelerations of Planing ^^^^

Monohulls in Head Seas

Dean Schleicher, P.E.

f^'^f.^ T H E F I R S T C H E S A P E A K E P O W E R B O A T SYMPOSIUM

A N N A P O L I S , M A R Y L A N D , M A R C H 2008

Discussion of Planing Boat Design

David Stimson, Stimson Marine/Boothbay Harbor Shipyard

Boothbay, Maine

The 19-1/2' Ocean Pointer planing at 15 knots with 25 hp

ABSTRACT

This is a non-technical paper based on the author's experience in designing and using economical low-powered planing boats. The discussion includes three designs in the 18 - 25' range that are designed to plane easily using 50 hp or less. Topics include the effect o f weight and hull shape on planing efficiency, handling, comfort and diyness, and aesthetics in boat design.

INTRODUCTION

When I was growing up in the 1960s, my stepfather often brought to my family's attention the fact that we as a societ)' were living a lifestyle based on a non-renewable resource - oil. He would point out how many calories o f fuel it took to produce and transport one calorie o f food, how much energy we were using for transportation, heating homes and water, and also for recreational uses. He made

us understand that there is a finite quantity o f oil accessible to us, that it is no longer being produced, and that therefore, the supply w i l l sooner or later run out. Yet, after forty years, in sphe o f our eai'ly prescient knowledge o f the situation, I don't believe that either he or I have significantly reduced our energy consumption. As long as each o f us feels that we are special, and therefore exempt from responsibilit)', the problem w i l l continue to escalate. With our present level o f knowledge and technology, there is no realistic alternative to o i l that can meet the world's demand for energy. Therefore, consei-vation is the only way for sui-vival in the short term. There are many ways we can consei-ve without giving up too much o f the lifestyle we have become used to. It is heartening to see that more and more people are finally taking the energy problem into their own hands - installing better insulation and more efficient lighting in their homes, supporting local agriculture and buying fuel-efficient cars. M y family and I now have a realistic goal to cut our energy use i n half

Economical

David Stimson/

Stimson Marine

Design

Boothbay, Maine

ing Powerboats

^^o^;^ T H E F I R S T C H E S A P E A K E P O W E R BOAT SYMPOSIUM

,71 A N N A P O L I S , M A R Y L A N D , M A R C H 2008

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Performance Prediction of Higli-Speed Planing Craft with Interceptors Using a

Variation of the Savitsliy Method

Srikanth Syamsundar, Stevens Institute of Tectinology, Hoboken NJ

Raju Datla, Stevens Institute of Technology, Hoboken NJ

ABSTRACT

A prismatic hull was used to study the effect o f interceptors on the performance o f planing craft. Interceptors are flat surfaces that are a small geometric projection o f t h e transom plane and cause an interruption in the water flow. This alters the pressure distribution on the hull bottom in a very dramatic manner leading to large variations in drag, running trim and heave. These parameters were measured in a model study using different interceptor penetrations, loads and center o f gravity locations. A n investigation o f the results shows that it is possible to predict the performance parameters using Savitsky's iteration method after accounting for the pressure induced due to the interceptor, the dynamic drag on the interceptor and variation in center o f pressure. A simple approximation to the drag force and an added normal force was derived and used i n conjunction with Savitsky's iteration method. The predictions are fairly consistent with the measurements. Addidonally the approximation for the added normal force was used to derive an equation for the non-dimensionalized added pitching moment.

NOTATION

a Distance between Df and CG (measured normal to Df)

A D Drag on Interceptor.

A N Added normal force due to interceptor ApM Added pitch moment due to interceptor A The area over which A N is assumed to

act.

As Total wetted spray area, b Beam

c Distance between N and CG ( measured normal to N )

A

C A L i f t coefficient = P y^j^i

~2

Dj. cos/?

Cf Friction drag coefficient = p 2 , , 2 2 ' CG Center o f gravity

CLP L i f t Coefficient for a planning surface with deadrise angle p

CLO L i f t Coefficient for a planning surface with deadrise angle 0 degrees

CLB Buoyant component o f l i f t coefficient. CLD Dynamic component o f l i f t coefficient. Cp The ratio o f the distance o f the center

of pressure fi-om the transom to the mean wetted length

V

Cy Speed Coefficient = D Total horizontal drag force d Draft o f the keel at transom

Df Viscous friction component o f drag (assumed acting parallel to the keel line, midway between keel and chine lines)

Dp Drag component due to pressure force, f Distance between T and CG measured

normal to the shaft line

g Acceleration due to gravity =32.2 ft/sec^

i Interceptor penetration Lc Wetted chine length

LCG Longitudinal distance o f center o f gravity fi-om the transom measui'ed along the keel.