Thistle (dinghy)

The Thistle is a high performance racing dinghy, also used for day sailing, popular in the United States. The Thistle was designed by Gordon K. (Sandy) Douglass who later designed the Highlander and Flying Scot. (These names commemorate Douglass’s Scots heritage.) Starting in 1945, nearly 4000 boats have been built, originally in hot molded plywood, and since the late 1950s in glass-reinforced polyester. The Thistle Class Association, with fleets across the country, holds local, regional, and national regattas throughout the year. All Thistles are built to the same lines by authorized builders, and the class rules limit innovations in rigging, and purchases of sails, and electronic navigation gear. Old and new boats are evenly matched, with the owner of Thistle number 1 winning the national championship in 1990. However old well used fiberglass hulls are often "soft" and not as competative at the higher levels of competition.

Thistle hulls are relatively light for their size, doing away with decking and spray protection to save weight. The sail plan is larger for the boat’s weight than in many other dinghies, making Thistles good light wind performers. Their hulls have wide flat bottoms, allowing the to boats plane (skim on top of the water) in winds of 15 to 20 knots. The sail plan is large, for the boat, consisting of a marconi rig with a main, jib and spinnaker.

Thistles are generally raced with a three person crew. A skipper, a middle and a forward person. The optimal total crew weight is generally 450lbs (US). However the crew weight is generally not the deciding factor in determining the outcome of the races. In all but the strongest winds, an experienced two person crew can manage the boat. Hiking straps are permitted for either droop or straight leg hiking, but a trapeze is not. The class is generally family friendly, however experienced sailors will still be challenged at the higher levels of competition.

The Thistle is used as the baseline for the U.S. version of the Portsmouth yardstick system for handicapping small boats in mixed-class fleets.

Specifications

• Length, overall: 17 ft (5.2 m)
• Length, waterline: 17 ft (5.2 m)
• Beam: 6 ft (1.8 m)
• Draft, board up: 6 in (0.15 m)
• Draft, board down: 4 ft 6 in (1.4 m)
• Sail area, main & jib: 191 ft² (17.7 m²)
• Sail area, spinnaker: 220 ft² (20.4 m²)
• Weight, all up: 515 lb (334 kg)