On Sunday 16 May 2004 3:15 pm in rec.boats.cruising Matt Colie wrote:


I am a naval architect and a marine enginer. The Mac 26* has not better
theoretical stability than most conventional monohulls. Did you know
that there is a MORC test that requires that a new or seriously modified
boat demonstrate static stability by tieing both head and main sails
(bagged to the top of the mast and then heaving the boat with all keels
and foils retracted down to until the mast is horizontal. The boat must
not flood. I do not like things that get less stable with incline (more
heel angle). Multihulls start loosing righting moment as soon as a hull
comes out of the water. They might be faster than most monohulls, but
they have some bad habits.

Whilst it is true that many multihulls can be badly behaved, it is
both possible and practical to build a multihull which is unconditionally
stable. James Wharram has written extensively on this point, you need
to keep the centre of effort low and limit the sail area. The clever
part of his designs is that when the going gets tough, such as the
hurricane that blows up suddenly out of nowhere, the sails are designed
to shred before the blow-down force is reached. Such incidents are rare,
but one should naturally carry spare sails B-).

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