Monohulls and catamarans, often equipped with
foils, trim tabs, and/or interceptors that control the
trim angle and minimize wave-induced motions,
are nowadays the most established concepts for
high-speed vessels. Interceptors are relatively new
concepts and are illustrated in Figure 7.5. The vessels
have transom sterns, that is, there is a flat
part of the aft ship below the mean free surface
that is perpendicular to the centerplane. Catamaran
designs include the wave-piercing and semi-
SWATH (small waterplane area twin hull)-style
hulls. The length of high-speed catamarans used
for passenger transportation in coastal water is
typically 30 to 40 m. Both monohulls and catamarans
longer than 100m have been built. Trimarans
and pentamarans are new types of multihull vessels
that are considered. They consist of a long
center hull with smaller outrigger hulls. The outrigger
hulls are important for static heeling stability.
The larger vessels are typically ro-pax ferries,
which means they carry passengers and allow rollon/
roll-off payloads, most often cars.