Pacific NW Section Hears Two Papers At Annual Spring Meeting

Members and guests of the Pacific Northwest Section of The Society of Naval Architects and Marine Engineers met recently in Victoria, British Columbia, Canada, for their annual spring meeting. A technical session at which two papers were presented was held at the Officers Club, HM Dockyards, Esquamalt. In the evening, the group enjoyed dinner and dancing in the Georgian Room of the Empress Hotel.

The first paper, "Concepts Explored in the Gulf Span Ferry Design," was presented by Capt.

Kieth Farrell, RCN (ret.) of Case Existiological Laboratories, Ltd.

The object of the paper was to emphasize the scope of work detail necessary when constraints are severe. The paper presents a summary of the alternatives which were studies for the new seagoing ferries required for the service between Sidney, Nova Scotia, and Port aux Basques, Newfoundland.

A seasonally varying load of passengers, cars, and tractor trailers was expected, justifying a large fast vessel. Comparative studies were made to compare costs of a one-truck onecar- deck vessel with a two-truck two-car-deck vessel of diesel and gas turbine propulsion, and of a split stern hull versus a conventional stern hull.

Subsequently, further studies were carried out for a vessel with a small load, beam and speed. The effect of these new constraints are described within the paper.

The paper includes 13 illustrations and an annex presenting general comments regarding the damage stability of passenger/ car ferries.

The second paper, "Submersible Barge Trim, Stability, and Control," was presented by Walter J. Bloehmhard, a naval architect from Langley, B.C. In his paper, Mr. Bloehmhard stated that a "natural trim" phenomenon occurs in all water ballasting and leaking sequence. The trim angle that develops can reach an alarming magnitude. In the early days of submersible drilling barge development, experimental design found the answers to some of the operational problems resulting from this cause. This phenomenon has been consistantly misrep- resented as an instability problem.

In reality, it is purely a flotation and trim problem. Accurate solutions can be found in terms of a simple extension of ordinary hydrostatic theory presented within the paper.

Mr. Bloehmhard's paper contains sections on flotation and trim, stability, movement of the points B, G, and M emplacement of a subsea facility and a dissension of the natural trim phenom- HAGGLUNDS PROBE CLAMP AUTO. BALE CLAMP enon. The paper concludes by pointing out that the problems of stability and trim for small submarine workboats have not been resolved to the same extent as for ships and semisubmersibles. Yet, this is a very important and fastgrowing field.

Copies of both papers are available through the Section librarian, C.S. Bracken, Todd Shipyards, P.O. Box 3806, Seattle, Wash.

98124.

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