Monday, March 14, 2011

Penn Yan Sea Bird - Design 176


This class of production boats was developed around 1936 as a keel boat sold at an affordable price, around $750 (at late '30s dollar values mind you). The design is interesting. The boats were built using Penn Yan's "monowood" construction method.


In simplified terms the boats were built upside down over a steel mold of 2 layers of planking: 3/16" on the inside and 5/16" on the outside, separated by a layer of asphalt impregnated canvas. The planks were forced into place, the inner planking running athwartships and the outer layer running longitudinally, and then the entire mass was fastened using 76 copper nails/square foot which were driven against the steel mold. As a result the nails were clinched tight.

The entire shell was then rolled and a minimal number of keel floors and a couple of longitudinal girders were installed. The deadwood was then installed as was the ballast keel.

Here are the plans.


If you told me this boat wouldn't last I would believe you. Here are a couple of recent images of a Sea Bird. Notice how the hull is grossly out of shape.



Quite a number of boats were sold. One of the most active fleets was at the Seawanhaka Corinthian Yacht Club of Oyster Bay, Long Island. The Penn Yans were such a disaster though that the boats were eventually developed in fiberglass and built by another builder. I would not be surprised if the new hull and decks were constructed and all fittings, rigging, spar and keel were stripped off the old Penn Yan hulls and they were then discarded.

The class was then renamed the Seawanhaka Sea Bird Class. By 1939 there were 28 boats in the Seawanhaka fleet alone.

Principal Dimensions
LOA 24'-0"
LWL 15'-0"
Beam 5'-9"
Draft 3'-6"
Displacement 1,700 lbs
Ballast 760 lbs
Sail Area 175 sq ft

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