50'+ fiberglass catamaran design plans

Hi guys does anyone have any recommendations for pure fiberglass catamaran design plans in the 50-60' range? I don't want to use plywood or any core materials like pvc foam, etc.

Thanks for any advise or tips!

 

I cannot recommend anything as such, but the first that springs to mind is the Derek Kelsall designs -
Catamarans - Kelsall Catamarans - Sail Design Range Over 46 Foot http://www.kelsall.com/Designs/KSSSailOver46.htm

Correction, I think that most, if not all, of his designs have cores.

I think you will be very limited in choice really re finding plans for a single skin catamaran of this size.
What do you want to use it for?
Why does it 'have' to be single skin fibreglass?

 

Hi Bajansailor thanks for your reply! It doesn't have to be but it is very difficult to get things like pvc foam core to my location. Bringing in just fiberglass and resin is logistically much easier and I like the fact that it requires less maintenance since it won't suffer from rot or water intrusion issues like plywood and foam core.

 

For a 50...60 footer, aluminum or steel begin to enter the realm of practicality. Neither of those will absorb water and does not rot. Steel or Aluminum is easier to repair, does not develop gel coat cracks, and several other advantages,........... cost among other things.

 

Building a mould for an all glass boat is as much work as the boat, no?

 

Mario, have you finished the Woods cat (I think she is a Romany?) that you were building?

I would agree with Messabout, re aluminium for a 'one off' boat of this size - it is (IMHO) pretty much the most logical way to go.

And re Fallguy's comment above, why would you want to build a mould for a one off boat? You already have to build two hulls; assuming that they are symmetrical you would then have to build three (and then some).

 

I don't see any advantages in single-skin composite catamaran hull. Will be too heavy!
Besides all, full set of molds/tooling will be required.

 

I am not sure there is a diplomatic way to explain the reality,several have posted pointers that hint at the essence of the matter.If plans don't exist,a designer would be needed and he will require payment for the work.A set of moulds will be needed and in order to get there,a set of plugs will need to be built.We don't know the enquirer's actual level of experience of these processes or his financial capability to undertake the project.I would guess-a very wild guess-that a couple of million dollars would get a boat built.There are catamarans for sale for less and they have enough of a reputation in the marketplace to have some resale value.Does a first time amateur build have much value?

 

Ron is a great guy, but he probably is not realizing the plug and mould aspect of all glass.

A bigger cat in ply/epoxy is far faster.

 

Hey guys thanks for all the great replies and advice! Is it possible to set up bulkheads and stringers like a typical plywood/epoxy /fiberglass build and instead of using plywood, use flat panels of fiberglass? I can make a flat sheet of several layers of fiberglass that would be relatively stiff but still bendy enough to make the hulls then reinforce it with more fiberglass once it's on the structure. I can make long flat panels of fiberglass pretty easily with hdpe sheets as the "mould". I know that it would be heavier but I'm not too concerned with efficiency since this would be for coastal cruising at most and would never likely have to cross any oceans. I figure there must be a good reason why this wouldn't work but I can't think of it.

 

Cats are weight sensitive. It is gonna get too heavy solid frp. You can't say weight doesn't matter.

 

Thanks Dan I was planning to make the hulls fatter to make up for the weight issue since I won't need skinny hulls. Plywood is not out of the question and I do have access to 3/4" plywood marine grade locally but nothing smaller than that. Could I use 3/4" plywood for a 50-60' catamaran? I used 3/8" plywood for the woods flica 34' so Im worried 3/4" would be too thick

 

In such a case, it would be preferable to use monolithic or sandwich PRF, which is much lighter than plywood.

 

Thanks for the reply tansl! By monolithic so you mean pure fiberglass? Also what do you mean by sandwich prf?

 

The monolithic is formed by several layers of fiber assembled by resin. In the sandwich construction, a central core is placed, which is very light and not very resistant to tension/compression, and layers of fiber on both sides of the core.