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
GSL-class service barge pontoon GSL-class service barge pontoon A GSL service barge pontoon is a non self-propelled yardcraft built by Goa Shipyard Limited for the Indian Navy. The pontoon is a catamaran having rectangular shaped, flat-bottomed hulls. The hulls are connected by trusses of round pipes and steel deck transverse beams. Each hull is divided into eight watertight compartments. The pontoon have cylindrical rubber fenders of 600 mm O.D. installed on both sides to absorb impacts and low reaction loads. Structural provisions have been made for vertical roller fenders at the forward and aft corners on the side facing the ship. The fenders are