[PCW] Nose-diving

[Malcolm Tennant]

The major difference between a sailing catamaran and a power catamaran is the
presence of a rig on the sailing vessel. The centre of effort of the rig will
be quite a long way above the deck and the centre of lateral plane will be
below the surface of the water. This difference in position produces a large
turning moment. In some conditions this is trying to capsize the boat. In
others it is trying to drive the leeward bow down. So remove the rig and
essentially both of those conditions disappear. Without the rig the forces
trying to capsize the power cat or drive its bows under are considerably less
than those operating on a sailing cat. However it continually surprises me
that so many people expect the sailing cat and the power cat to behave the
same. How many times have I heard the "catamarans capsize" comment applied to
power catamarans in the last 30 years!

Regards,

Malcolm Tennant.  ARINA  MA


MALCOLM TENNANT MULTIHULL DESIGN LTD
PO Box 60513, Titirangi.
Waitakere 0642
NEW ZEALAND
Ph: +64 9 817 1988
e-mail: malcolm at tennantdesign.co.nz
www.tennantdesign.co.nz
www.catdesigners.com