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Chesapeake Section Meets And Hears Two Papers At Naval Ship Research And Development Center The Chesapeake Section of The Society of Naval Architects and Marine Engineers held the sixth meeting of its 1972-73 technical pro- gram on March 14, 1973, at the Naval Ship Research and Development Center in Carde- rock, Md. The meeting began with a demonstration of a SWATH ship in waves in the Maneuvering and Ssakeeping Basin at the Naval Ship Re- search and Development Center. The group was also given a tour of the David Taylor Model Basin, which is over 3,000 feet long and one of the finest examples of a hydrodynamic towing tank in the world. The model basin has two parallel tanks, the first being a deepwater tank which is 22 feet deep and 51 feet wide, and the second being a high-speed facility capable of testing advanced ship concepts re- quiring high speeds in excess of 40 knots. This tour was followed by the social hour and din- ner. which were enjoyed by approximately 190 members and guests. Vice chairman Seth Hawkins opened the meeting by welcoming those in attendance and introducing distinguished visitors, including Phillip Eisenberg, national president of SNAME, Charles Zeien, executive vice presi- dent of J.J. Henry Co., Inc., and Capt. P.W. Nelson, Commander, NSRDC. After completing other normal Section busi- ness and after a few welcoming remarks by Captain Nelson, vice chairman Hawkins in- troduced R. Wermter, Chief, Ship Powering TELEPHONE/AREA CODE 504-384-3060 Principals of the Chesapeake Section meeting shown above at the Naval Ship Research and Development Center, left to right: R.J. Boswell, NSRDC, author; G.G. Cox, NSRDC, author; Phillip Eisenberg, national president, SNAME; Seth Hawkins, vice chairman, Chesapeake Section; R. Wermter, NSRDC, technical session moderator; Capt. P.W. Nel- son, Commander, NSRDC; C. M. Lee, NSRDC, author, and R. M. Curphey, NSRDC, author. Division, NSRDC, the moderator of the tech- nical session. Mr. Wermter stated that there would be two papers and introduced the five authors, representatives of the Ship Perform- ance Department, Naval Ship Research and Development Center, as being among the fore- most authorities in their fields. The authors of the first paper were C.M. Lee, R.M. Curphey, and H.D. Jones (Mr. Jones was not able to attend the meeting), and the tit'e of their paper was "Prediction of Motion and Hydrodynamic Loads of Catamarans." The authors summarized the reason for their work as follows: "A large useful area is one of the obvious advantages associated with catamarans. If this large deck area is to be ef- fectively utilized, it must behave as a stable platform. Thus, the advantages associated with catamaran hull forms may not be fully realized unless they have good seaworthiness character- istics which can compensate for the increased frictional resistance due to the increased wet- ted hull surface and the added structural prob- lems resulting from the cross-deck structure between the two hulls." Therefore, there is a definite need to develop analytical techniques to study the motion and hydrodynamic loads of catamaran-type hull vessels. This paper is a summary of the results of their efforts to ac- complish this task. The authors of the second paper were R.J. Boswell and G.G. Cox, both from the Ship Performance Department at NSRDC, and the title of their paper was "Design and Model Evaluation of a Highly-Skewed Propeller for a Cargo Ship." This paper presented the design process and model evaluation of a highly skewed propeller as compared to a normal propeller for a mod- ern cargoship. The design process was dis- cussed in detail, including considerations of cavitation, mean and fatigue strength, and pro- peller-excited vibratory forces. Model experi- mental results were presented which confirm the validity of the design process and show that the highly skewed propeller possesses pro- pulsion performance comparable to the nor- mal propeller now fitted to the ship, has less tendency toward cavitation erosion than the propeller, and possesses adequate strength for ahead and steady astern operation. Theoretical calculations indicate that the highly skewed propeller will produce lower vibration excita- tion forces than the propeller currently fitted to the ship. "Conrad builds barges with remarkable cost efficiency" CONRAD I NDUSTR I E S , INC. P.O. BOX 790/MQRGAN CITY, LA. 70380 Authorized Marine distributor for Westinghouse Turbine Renewal Parts, Port Electric maintains a complete stock of replacement parts in its own warehouse for immediate delivery. 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