Trimaran sailplan. They contribute to drag when heavily immersed, and their level of immersion indicates when to reef. Two types of trimaran exist: the regular trimaran and the open trimaran, which features a trampoline between the hulls instead of plating. Trimarans have a number of advantages over comparable monohulls (conventional, single-hulled sailboats). Given two boats of the same length, the trimaran has a shallower draft, a wider beam, less wetted area, and is able to fly more sail area. In addition, because of the righting moment provided by the wide beam, trimarans do not need the weighted keel that is required
Junk rig running rigging which pulls up the junk sail are: The running rigging which pulls down on the junk sail are: The running rigging that sets or trims the junk sail (controls the angle of attack relative to the direction of the wind) is the "sheet". On a traditional Chinese junk rig, the sail is controlled by "sheetlets"—small sheet lines running from the battens to blocks that in turn are on lines running through a "euphroe," a long piece of wood with holes in it. This helps maintain uniform tension in each panel of the sail. Western ship designers Tom Colvin,