Small Waterplane Area Twin Hull

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The waterline of a SWATH ship is the only distinction between it and a catamaran
The waterline of a SWATH ship is the only distinction between it and a catamaran
A SWATH ship resembles a catamaran.  The twin hulls (blue) remain completely submerged.
A SWATH ship resembles a catamaran. The twin hulls (blue) remain completely submerged.

The Small Waterplane Area Twin Hull (SWATH) is a twin-hull ship design that minimizes hull volume in the surface area of the sea. By minimizing hull volume in the sea's surface, where wave energy is located, the vessel becomes very stable, even in high seas and at high speeds. The bulk of the displacement necessary to keep the ship afloat is located beneath the waves, where it is less affected by wave action, as wave excitation drops exponentially with depth. Placing the majority of the ship's displacement under the waves is similar in concept to submarines, which are also not affected by wave action.

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[edit] Effects

The twin-hull design provides large, broad decks and a stable platform. The main disadvantages to the SWATH hull form are that they are more expensive than conventional catamarans, require a complex control system, have a deeper draught than catamarans and mono-hulled ships, and a higher maintenance requirement. Furthermore, SWATH vessels can use up to 80% more power than an equivalent catamaran, and are more limited in speed compared to equivalent catamaran vessels.[1]

[edit] History

The SWATH form was invented by Canadian Frederick G. Creed, who presented his idea in 1938 and was later awarded a British patent for it in 1946. It was first used in the 1960s and 1970s as an evolution of catamaran design for use as oceanographic research vessels or submarine rescue ships.

[edit] Specific examples

Research ship Planet of the German Navy
Research ship Planet of the German Navy

[edit] See also

[edit] References

  1. ^ British Columbia Ferry Corporation: "Fast Ferries Technical Notes" 1995

[edit] External links

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