Machinery Characteristics

Robert T. Young, president of The Society of Naval Architects and Marine Engineers, has announced the complete schedule for SNAME's 86th Annual Meeting to be held on November 16-18, 1978, at The New York Hilton Hotel.

The meeting actually begins on Wednesday afternoon, November 15, with the yearly Council meeting.

Technical sessions take place Thursday and Friday, and the evening events include the Annual Banquet on Friday and the Dinner-Dance on Saturday.

At the simultaneous technical sessions, 14 papers will be presented.

These have been specially selected so they present enough variety to interest all the attendees.

President Young will give his final message as president at the President's Luncheon in the Sutton Ballroom on Thursday the 16th. Featured on the program will be the presentation of several important awards—the Cochrane Award and the Joseph Linnard Prize. In the afternoon, at 4:00 p.m., the Annual Business Session will be held, where the members will act to elect a new president for a two-year term beginning January 1, 1979.

On Friday evening, the 17th, the Annual Banquet will take place in the Grand Ballroom. After the dinner, the Taylor, Land, and Davidson Medals will be presented.

The Banquet speaker will be Charles W. Robinson, vicechairman, Blyth Eastman Dillon & Co., Incorporated.

The David W. Taylor Medal, "For Notable Achievement in Naval Architecture and Marine Engineering," will be awarded to John J. Nachtsheim, Assistant A d m i n i s t r a t o r for Operations, Maritime Administration. The Vice Admiral "Jerry" Land Medal, "For Outstanding Accomplishment in the Marine Field," will be given to Rear Adm. William M. Benkert, USCG (ret.), president of the American Institute of Merchant Shipping. The Davidson Medal, awarded every other year, will be presented to Dr. Louis Landweber, p r o f e s s o r and research engineer, University of Iowa.

The 14 technical papers to be presented are: Paper No. 1—"Ship Sway, Roll, and Yaw Motions in Oblique Seas" by Rodney T. Schmitke.

Synopsis—A theoretical model is presented for the prediction of ship sway, roll and yaw motions in oblique seas. The low-frequency behavior of this model is examined, with emphasis on beam seas.

The prediction of roll damping is discussed in detail, including examples.

Extensive comparisons of predicted and measured roll response are made.

Paper No. 2—"Wave Statistics for the Design of Ships and Ocean Structures" by Michel K. Ochi.

Synopsis—This paper presents wave information needed for predicting responses of ocean systems in a seaway, specifically for design consideration. A series of wave spectra to be used for shortterm, as well as a series for longterm ( l i f e t i m e ) predictions are developed. Numerical computations are made on a semisubmersible platform; results are compared with those using wave spectra measured at various global locations.

Paper No. 3 — "Analysis and Control of Distortion in Welded Aluminum Structures" by Koichi Masubuchi and Vassilios J. Papazoglou.

Synopsis — Results of recent investigations on the subject are summarized. Three kinds of welding distortion are analyzed: longitudinal bending distortion, outof- plane angular distortion, and buckling distortion. Experimental results are presented and compared with predictions obtained by computer programs.

Paper No. 4 — "Effect of Hull Girder Stiffness Variations on Ship Structural Performance" by J. Harvey Evans and Roger G.

Kline.

Synopsis — A review of possible hull-stiffness problems reveals no cause for concern over insufficient stiffness per se. More relevant are whipping bending stress components from slamming or fatigue from springing. A procedure, based upon the "dynamic load factor" concept, is proposed for estimating whipping bending stresses during preliminary design, as a function of hull stiffness.

Paper No. 5 — "Analysis of a High-Power Water-Cooled Electric Propulsion System" by D.L.

Greene, C.J. Mole, W.P. Welch and W.R. Seng.

Synopsis—The results of a study of a new class of water-cooled d-c electric machinery, as applied to a destroyer-type ship, are reported.

The high-power density of this machine type makes it possible to take advantage of the arrangement and control flexibility of electric machines, without a volume and weight penalty. A description of expected ship performance and principal machinery characteristics is presented.

Paper No. 6—"Feasibility and Comparative Studies for the Use of Prestressed Concrete in Large Storage/Processing Vessels" by Ben C. Gerwick Jr., A.E. Mansour, Edward Price and A. Thayamballi.

Synopsis—The use of prestressed concrete for constructing storage/ processing vessels and oceangoing liquefied gas carriers may have certain advantages. The technical feasibility and safety of a 300- meter-long prestressed concrete vessel c a r r y i n g LPG in freestanding tanks is analyzed and evaluated. The results are compared with similar analysis of a steel hull designed on the basis of ABS requirements.

Paper No. 7—"Design of Bulbous Bows" by Alfred M. Kracht.

Synopsis—A quantitative design method for bulbous bows is presented, together with the necessary data, providing relationships between performance and main parameters of ships and bulbs.

The derived design charts show the power gain as functions of bulb parameters and allow the calculation of the required power of a bulb ship.

Paper No. 8 — "Prediction of Steady and Unsteady Marine Propeller Performance by Numerical Lifting-Surface Theory" by Justin E. Kerwin and Chang-Sup Lee.

Synopsis — A numerical liftingsurface theory for marine propellers has been developed at M.I.T., for use as a practical tool in the solution of both steady and unsteady flow problems. This paper presents a view of the theory and a description of the numerical methods employed, followed by systematic tests establishing the numerical convergence of the procedure and a number of specific comparisons with published experimental and theoretical data.

Paper No. 9 — "Hull Experiments on 24-Knot RO/RO Vessels Directed Toward Fuel-Saving Application of Copper-Nickel" by Eugene Schorsch, Richard T. Bicicchi and John W. Fu.

Synopsis—To evaluate coppernickel as a hull material in clad or sheathed forms for large commercial vessels, shipboard tests to determine Cu-Ni durability in h i g h - s p e e d vessel environment were performed. A rudder was sheathed and installed on a 24- knot ro/ro vessel; together with insulated and electro-chemically instrumented test panels. These tests indicated that the materials' erosion corrosion rates are within tolerable limits.

Paper No. 10—"Ice Effect Trials in Arctic Waters on CCGS Louis S. St. Laurent" by Peter G. Noble, Roderick J. Allan, Malcolm Dunne and Brian Johnson.

Synopsis — An Arctic probe was made in May 1977 with the CCGS Louis S. St. Laurent. Tests were carried out during the voyage from Nova Scotia to the western end of Lancaster Sound. Ship motions, accelerations and ice loads on the hull also were measured and are reported together with details of ice properties testing and the ship instrumentation system.

Paper No. 11 — "New Finnish Barge Carriers for the U.S.S.R." by Veikko Koskivirta, Veikko Heikkila, Mikko Niini and Heikki Harjuvaara.

Synopsis—The Finnish shipbuilding and engineering company Valmet Oy is currently constructing two 36,600-dwt barge carriers for the U.S.S.R., based on the Lykes SEABEE concept. The paper gives a brief description of the design and construction of the vessels. Main particulars of the 3,000-ton-capacity barge l i f t i n g and t r a n s f e r r i n g arrangements also are given.

Paper No. 12 — "Development and Application of a Computer- Controlled Ship's Frame Bender in the Automated Shipyard" by James B. Acton, Filippo Cali, Thomas P. Mackey and H.W.

Mergler.

Synopsis—A unique ship's frame bender with self-adaptive computer numerical control (CNC) has been developed and will be installed at NASSCO's San Diego shipyard. The CNC bender is compatible with existing shipyard automation programs using offset data generated by the shipyard's host computer, to bend or straighten frames automatically, resulting in significant cost savings and increased production efficiency.

Paper No. 13—"Modern Heavy- Lift Ships: State of the Art" by H.W. Janecke and W.F. Muir.

Synopsis—Types and concepts of modern heavy-lift ships are described and illustrated. Basic design characteristics and requirements are also discussed, together with typical heavy-lift gear and transfer equipment. Operation of heavy-lift vessels is covered with respect to planning, crewing and cargo handling. Also presented is an in-depth description of the first American-built modern heavy-lift ship.

Paper No. 14 — "Systems Approach to Offshore Crane Ship Operation" by Dan Hoffman and Vincent K. Fitzgerald.

Synopsis — The evolution of offshore crane vessels is described in relation to present design philosophy and operation criteria.

Currently employed methods of on- and off-line analysis for predicting and minimizing downtime are discussed. Actual on-site data is presented to document the substantial improvements in operability achieved by vessels employing these methods. Particular emphasis is placed upon the onboard computerized and monitoring system (HELM).