Crowther catamaran deckhouse changes

[Dansplans]

Hi all. This looks like a great site for exchanging information. Nice to see all the imput from those that run it. I have been sailing since about the age of 12 when I stuck a broom handle in a 8'x2'x1' block of foam and hung a sheet on it 40 years ago. Made many moves up over the years to now owning a Crowther spindrift 37 extended to 42 feet. I have done some major repairs to this vessel over the past 2 years as the previous owner was, shall we say, neglegent. This catamaran has very restricted access into the hulls from the deckhouse. I am now looking to improve the access into the hulls of this boat. What I am looking for is someone to work with me as I have an idea of what will work constuction wise but need an opinion on the engineering side to make sure I do not impact the structural integerity of the area in question. With my backround in residential design I can supply drawings and pictures of the area in question and what I hope to accomplish. Anybody willing to take a look at my problem? The picture attached shows my boat just before I bought it and one of the previous owners blemishes when he tried to pick up a 14000 lb boat with a 9000 lb hand crane at a boat club. Droped it half on land and half in the water when the crane came down. Thanks, Dan

[masonhawes]

Hi!
I am just about to build a deckhouse on my Spindrift 37 and would like to exchange ideas about the problem of access to the hulls .

I have previously built a 27ft trimaran to my own design but am a mechanical engineer by training and have no formal boat design training but I hope to be of some help anyway.

mason

masonhawes@ausi.com

[dac]

I built a spindrift and then modified it for easier egress to hulls.
this added storage as well as easier access to hulls.

[catsketcher]

Hello

I have built a 38ft cat along with a few other multihulls (wwwfoldingcats.com) and have a friend who modified his Spindrift, it is called Blue Moon.

He started off by installing chamfer panels like Grainger and Schionning boats have on their inner hull sides. These panels were built from foam and made access much easier. They did take some time to install. A major part of the time involved was fairing in the panels to the hull and bridgedeck.

As for the laminate I think it was 12mm foam with 780 triax eack side. Lots of double bias tape on the joins would be good. Go to 1160 triax if you want it more bulletproof.

Then he ripped off the cabin top and had a new one made The new way of making a cabin top is to make them out of foam or duflex and bend the front brow of the cabin top to get the shape you want. He had a boatbuilder make his cabin top and then he faired it inside and out and then installed it. It had chainplates laminated into its sides and really increased the boats interior room. Taken together the two modifications really helped the boats livability.

The new cabin top is designed to look like a Crowther Catana so the Crowther lineage is stil there and the boat doesn't look like Frankenstein's monster. The Blue mooners are cruising this year and I can give you their email if you get back to me at

info@foldingcats.com

As to the engineering I wouldn't worry too much about doing it from first principles. Although it can be intelectually satisfying to do this from first hand the lack of real load data means your laminates will be guesses anyway. Find a similar boat that is proven and do the same is a good method

cheers

Phil

www.foldingcats.com
info@foldingcats.com