“The Thistle is a high performance one-design racing dinghy, also used for day sailing, popular in the United States… The current hull configuration uses a glass-reinforced polyester molded boat with wooden rails, centre board trunk, thwart, fore grating, and aft grating. The spars were once made from spruce, but are now of entirely extruded aluminum construction…
Thistle hulls are relatively light for their size; they have no decking or spray protection, which saves weight. The sail plan is large for a boat of this size, consisting of a marconi rig with a main, jib, and symmetrical spinnaker. The sail plan is larger for the boat’s weight than in many other dinghies, which makes Thistles perform extremely well in light wind. Their hulls have wide, rounded bottoms, allowing the boats to plane in winds as low as 10 knots. It is not uncommon to see thistles efficiently making their way, while other dignhys of similar design are becalmed.
Thistles are generally raced with a three person crew: a skipper, a middle, and a forward person. The optimal total crew weight is generally 450 lb to 480 lb (US) depending on wind. The crew weight, however, is generally not the deciding factor in determining the outcome of the races. In fact, class rules do not limit crew weight. 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, though experienced sailors will still be challenged at the higher levels of competition.”
Read more in the Wikipedia article on the Thistle sailboat.