Pics of Sigma 36 From Ad on YachtWorld
Specs from ad
LOA - 36
Beam 10'3"
Displacement 15,000 Lbs
Draft - 6'

From the original brochure... "The SIGMA "38" is basically a performance boat. designed to win. and with a layout planned for efficient racing, from her workable navigation nook to her large sail locker in the forepeak. But she is no racing machine alone, with the compromise in comfort that implies. Attention has been paid to cruising comfort and the other details that makes "boat" a "yacht". The lavish use of rubbed teak below lends a richness and warmth below that is usually lacking in a fibreglass boat, and 27 drawers, 15 lockers, and 9 shelves eliminate the stowage problem. A large dining table with bottle locker is standard. The installation of the engine below the cabin sole opens up the area aft usually taken by the engine box, resulting in a unique layout with the most usable room of any 38 footer we know. The quality of the teak joiner work equals that of any builder in the world, placing the SIGMA "38" in the Custom category, but at a stock boat price."

LOA - 38'4"
LWL - 27'6"
Beam - 10'3"
Draft - 5'10"
Sail Area - 651sq'
Displacement - 18,000 Lbs

"....The SIGMA represents the peak of development of the moderate displacement fin keel/spade rudder concept by Sparkman & Stephens, America's leading Naval Architects.  The SIGMA is one of the first fibreglass auxiliaries to incorporate the modifications learned from the INTREPID program:  full "skeg" between fin and rudder, which tank testing has shown to greatly stabilize the flow of water in this critial area, reducing resistance from the quarter wave.   Adequate rudder control under certain conditions of wind and water has proved to be a real problem in earlier spade rudder designs, especially those with balanced rudder, but the new SIGMA is as stable and fully controllable as more traditional designs.  She is available with masthead or 15/16 rig, and the estimated 1967 CCA RATING is 30.5 and 30.0 respectively."