As for draft and beam back in the 90s when the RAN were looking at OPV concepts and designs one of them was from Incat who make those big North Sea wave piercing catamaran ferries.

Draft catamaran meaning. 32 47 Cabin Cruiser. 18 32 Draft. They were quite interested in Incat design because of its capability to operate a helo and still operate in extremely shallow water so Im somewhat dubious that a really big cat would have a much deeper draft.

A downside to a catamarans shoal draft is that it not as stable in very turbulent waters when far out to sea. Catamarans do not require this and therefore tend to have a shallower draft. Manufacturing excessively wide catamarans is like trying to market monohulls with super deep-draft keels.

However not all shallow draft boats have a flat bottom. It is a geometry-stabilized craft deriving its stability from its wide beam rather than from a ballasted keel as with a monohull boat. The shallow draft is especially appealing allowing for use in shallow water and giving the captain the option to pull the boat right up to shore without worry.

In comparison to sailboats catamarans draft is 1 12 meter in comparison to the sailboats whose drafts are 19 23 meters long. In order to sail with the wind direction either forward or abeam a catamaran must be either of a deep draft design or if shallow draft it must be sailed with the centerboard extended so that the effect is that of a deep. They Have A Smaller Draft Speaking of catamaran benefits lack of keel results in a smaller draft.

Access Catamarans especially the lagoon catamaran have a shallow draft and can therefore go through shallow waters that the monohull cannot. Most early narrow-beamed catamarans suffered from this phenomenon Ultimately a boats design has a major influence on its ability to stand against the forces of nature and to keep occupants safe. How much does she draw means what is the minimum depth of water that this boat needs so she doesnt go aground.

A cruising catamaran will draw less than 3 foot allowing access to areas that would terrify a monohull. Both are totally impractical. They are also often lighter and have less wave impedance therefore sometimes making them faster than a monohull especially when sailing at reaching angles.