Cats are small racing catamarans used for racing and personal use.
Compared to other small sailboats, Hobie Cats are appealing because
they offer high performance at a relatively low cost.
In 1967, Hobie designed the Hobie 14 Catamaran.
Hobie wanted to make a boat that you could easily launch into the
surf from the beach, sail, and bring back through the surf. In 1969
Hobie released the Hobie 16, the most popular catamaran ever and
the most competitive catamaran class in the world. Over 100,000
Hobie Cats are sailing around the world.
The boats are considered by many to be overpowered
by design due to their light weight, efficient hull design, and
large sail area. On the other hand, many seek out the Hobie 16 for
precisely these reasons. They can reach high speeds over 17 knots
(20 miles per hour) due to efficiency gained from "flying"
a hull. When flying, one of the boat's hulls is lifted out of the
water due to the angle of the boat. As well as reducing drag from
the water, this also takes advantage of the hulls' asymetric design,
each hull being shaped to provide a sideways upwind force. With
both hulls down, the hulls' sideways forces cancel each other out.
The Hobie 16 is surprisingly stable when flying a hull as increasing
tilt causes wind to spill from the top of the sail, thus reducing
turning moment. Conversely, reduced tilt results in a more vertical
sail, thus increasing turning moment; so the boat is self-stabilizing
to some degree when flying a hull.
Catamarans are inherently more stable
than monohulls but some Hobie cats such as the 16 and 14 have hull
designs that don't have a lot of buoyancy in the bows which results
in some spectacular "pitchpoles". Most frequently a capsized
boat will lie sideways with the sail and mast floating. The hollow
aluminum mast is designed to be sufficiently buoyant to hold the
boat at 90 degrees from vertical even under extreme conditions.
But if the mast leaks, the boat may "turtle" (turn completely
Righting a Hobie is a required skill
in high winds. Righting is the technique used to lift the boat such
that it is ready to sail again. If one imagines a small catamaran
sail boat lying on its side, one hull will be floating at the water
line and the other hull will be supported about 8 ft above the water.
By casting a line over the top hull, standing on the lower hull,
and pulling, the sailor can pull the Hobie back into position to
continue sailing. This task is easier if the sailors first rotate
the bows into the wind by moving their weight forward; the wind
can then help lift the sail from the water. Righting is more difficult
when there is no wind to help, or if waves are large. Most racing
Hobies have a permanently fitted righting-line under the trampoline,
held out of the way when not in use by a system of pulleys and bungee-cord.
To counteract their tendency to capsize,
sailors have the opportunity to use a "trapeze" system
whereby they wear a harness and attach themselves to cables suspended
from the mast. Thus suspended, the sailor places his/her feet on
the edge of the boat and sits out over the water, providing more
torque to hold the boat down. When the sailor's body is parallel
to the water, they are providing maximum torque.
It is possible to sail a Hobie 16 (at
very low speed) without even hoisting a sail, relying only on the
shape of the mast for propulsion.
The Hobie 16 is one of the few small
sailing boats that can be rolled end-over-end.
Hobie cat rudders (one per hull) protrude
quite some way below the hulls. To prevent damage from the bottom
or underwater objects, they have a spring-release mechanism that
allows them to snap to a horizontal position. Hobie cats draw very
little water and can sail in as little as 4 inches of water when
lightly loaded and with the rudders up.
article from wikipedia