the facts are that a wave 55% the size of the LOA
will knock down a monohull. This is Not the least size wave, it is the size that will likely result in the knock down. A knock-down being defined as a 90 degree heel wherein the mast
touches the water
without necessarily dipping below.
is defined for a heel that exceeds 90 degrees and the mast
dips below the water
I have ordered two Catamaran books
- Chris White's book and Gregor Tarjan's book - and hope to get them in a week or so (amazon shipping
can be slow even if they ship the same day you order).
Maybe in the two catamaran books
of thumb will be offered as to what wave will knock-down or capsize a catamaran but I have not seen or read anything to offer such, as of yet.
The difference in a knock-down or capsize for a monohull and catamaran is that the monohull will right itself whereas a catamaran likely will not (at least not that I know of or have heard of)
Formulas such as ballast to displacement
ratios, angle of vanishing stability, and the capsize screening formula are used to ascertain seaworthiness of monohulls. for multihulls, is there a set of formulas to ascertain vessel seaworthiness?
And yes, the skipper
and crew can add or subtract greatly but all things being equal, the formulas determine a monohull's ability to right itself, resist knock-downs and capsizes.
When I stated that in like sea conditions, a monohull is more likely to sustain a knock-down or capsize than a multihull, I was considering the beam of the vessels and how it would effect such an event.
Narrower beam monohull veesels generally are quicker to heel but more resistant to knock-downs, newer model, wider beam vessels resist heel but can be knocked-down easier than the narrow beam designs.
This is why, among other things, the Alberg 30
is a much more capable bluewater cruiser than a new Beneteau Oceanis
323. And I am deliberately eliminating factors such as ballast displacement
ratios, size and shape of keel
I have stated I know little about multihulls and that is why I posed a question here. But, I have sailed, know how to sail; albeit, I am not an expert, and have a pretty decent knowledge of monohull boats, designs and principles that make them bluewater seaworthy
or not. I certainly would not criticize someone for selecting a monohull nor would I scoff at someone who selects a multihull. I want to know what makes each the better boat and what deficiencies make them the lesser boat.
Lastly, this does not take into account the boats, that could in no way be considered seaworthy
, have crossed oceans. Webb Chiles did it in an open 18 foot boat. But I doubt if I will ever meet anyone that adventurous.