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
Navy lighterage pontoon wedge pins. The flotation blocks came in two types: The principal type of unit was a rectangular prism; the majority of NLPs were constructed using these. The second type was similar but curved upward on one side, and these boxes were used to make bows on the front of NLP barges when required. Navy lighterage pontoon The Navy Lighterage pontoon (NLP) was a type of pontoon developed in World War II by the US Navy and used by naval construction teams (Seabees) and specialized US Army combat engineers, on invasion beaches and shallow harbors or harbors where the facilities had