February 1977 - Maritime Reporter and Engineering News

SNAME Philadelphia Section Hears Technical Paper On Pipelay Barge SEMAC I At Past Chairman's Night

The Philadelphia Section of The Society of Naval Architects and Marine Engineers held its third meeting of the 1976-77 season at The Engineer's Club in Philadelphia, Pa.

It was also Past Chairman's Night and was a pleasant occasion for renewal of old friendships for the 65 members and guests.

Following a social hour and dinner, a short business meeting was conducted. The Section chairman, Anthony C. Brown, formally opened the meeting by introducing all the past Section chairmen who were present.

A gold service commendation pin was presented to Maurice M. Morris for his outstanding services as the previous year's chairman of the Section. He was also presented with a "Certificate of Appreciation" in recognition of his efforts.

The technical session was opened by Edward J. Ciechon, meeting coordinator, who introduced Dr. Paul L. Rohmaller, project engineer, SEMAC I Project, author and presenter of the evening's paper entitled "Pipelay/Derrick Design for Rough Seas." The paper, along with a film presentation, discussed SEMAC I, a large semisubmersible pipelay/derrick barge designed specifically for use in rough sea areas. The barge will be capable of installing large-diameter pipeline in water depths exceeding 1,200 feet.

SEMAC I was designed to initially operate effectively in northern North Sea-type water depths and sea conditions. It utilizes the well-known semisubmersible concept, which provides a motion-reduced mobile platform to conduct operations in the design sea state of 15-foot significant waves. The twinpontoon variable draft feature also allows the barge to elevate all exposed deck machinery and other facilities well above the wave crests in the most severe seas without "running for shelter." The large size (433 feet long overall by 180 feet wide by 91 feet deep) provides adequate work and storage space and contributes to its reduced motion and increased stability.

SEMAC I was constructed by Alabama Dry Dock and Shipbuilding Company (ADDSCO), Mobile, Ala. ADDSCO constructed the barge by building components and then erecting these components using a large gantry crane. Detailed engineering for SEMAC I was accomplished by ADDSCO, J.J. Henry Co., Inc. and John Mackin and Associates.

The author concluded his timely and informative paper by summarizing the pipelay barge optimum design, reliability, and widetruss stinger concept.

The technical session was finalized with formal oral discussions by J.E. Abel, chief, Electrical Department, J.J. Henry Co.; K.

Gyswyt, chief, Scientific Department, J.J.

Henry Co., and R.B. McFadden, chief, Machinery/Piping Department, J.J. Henry Co.

Philadelphia Section chairman A.C. Brown presented Dr. Rohmaller with a "Certificate of Appreciation."

Other stories from February 1977 issue


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