The S&S collaboration with Tartan involved 14 models between 1960 and 1984 with a total of some 3,400 boats built. The first S&S design was the Tartan 27 and the last was the Tartan 40
Tartan asked S&S for a new cruising boat design in May of 1978. Reportedly, sales of the T34 and T30 were slowing and a new design was needed. According to the S&S press release:
The Tartan 33 was introduced to the yachting public on July 1979. The T-33 was designed as a comfortable cruising boat with good sailing performance. Many of the lessons learned on the Tartan Ten were incorporated into this design. The trials aboard the T-33 and the sale of more than forty units to date confirm that the design targets have been met. A comfortable cruising boat for deep water and shallow water. In addition, a yacht which is easy to sail and still capable of performing on any point of sail under varied conditions.
Did the final product match the original specifications from Tartan? Not exactly, but then designs have a habit of evolving. Tartan originally requested a 7/8 fractional rig, spade rudder, 33′ overall, a deck-stepped mast, a basic weight of 9,500 lbs. (assuming 4,400lbs of ballast) and a Scheel keel or centerboard. The boat manufactured came with a keel-stepped mast and was about 1,000 lbs. heavier. Obviously there was no centerboard version. The navigation station and connection to the quarter berth was successful on the Tartan 37 and translated to the T33 design.
In August of 1981 the basic T33 design was modified to include a deep fin keel, a different rudder, and a masthead sail plan. This was the T-33R (racing) design.