View Full Version : Building a 40' Offshore Cat, Need help please...


alwayskaos
12-28-2007, 02:22 PM
I have a wrecked late model 40' racing cat that I have cut up and customized for a mold. Boat is 40'x12'. Externally the boat is complete and looks perfect with a new gelcoat.
Can anyone recommend a layup process, and possibly a steel support system? I tend to over do things in regards to engineering, but since this is a personal project with the primary builder myself, I need to keep expenses reasonable. Not exactly sure of layup layout. I was going to use a Biaxial Combo Mat for the first layer over the gelcoat. Not really sure. How thick would it need to be, and what would a thickness cross section consist of?

Any help would be tremendously appreciated!!!
Thank you!!

TeddyDiver
12-29-2007, 04:05 AM
I'm no expert in this but without knowing how many times (one-200?) you are planning to use the mold it's no simple answer..

alwayskaos
12-30-2007, 12:46 PM
1 need one boat from the mold, but I would like to make it proper in order to sell the mold after my hull is complete. If anyone has experience in this, please share. My hull is complete ans sitting on blocks ready to go.
Thanks again.......

TeddyDiver
12-31-2007, 01:07 AM
As a "thumb" rule: After gelcoat make a laminated layer as thick as the original hull (incase 40' hull about 20mm) Add "ribs" (2'' tubing laminated aswell 20mm c/c 500mm) Add steel frame to support the mold.

alwayskaos
12-31-2007, 12:48 PM
Thank you very much for the reply.

I guess thats about what I figured.
So would the 20mm laminated layer be all fiberglass?

Also, what exactly did you mean by: (2'' tubing laminated aswell 20mm c/c 500mm)?


Could a chopper gun help help time and costs down?

Sorry for all newbie questions, but some of you have much more experience than I do in this area,,,,,,,,just need to pick some brains!!

Once the bottom hull was laid up, I was going to weld up a frame structure consisting of larger perpendicular U channels ,which go under the hull from side to side. These would be welded up with paralell beams from front to back with casters on the bottom.
Thank you

masalai
12-31-2007, 09:08 PM
40 ft LOA? by 12 ft beam? for a monohul? A cat that length one would expect a beam of between 20 (skinney & OK for power only) to 26 ft beam or wider if racing hulls. Can't be bothered when I saw 12 ft beam for a cat - stupid that for cruising.

If powered race boat different ball game. Your play..........

alwayskaos
12-31-2007, 10:07 PM
It is a twin engine offshore performance race boat, similar to a Skater or Nortech.

View Full Version : Building a 40' Offshore Cat, Need help please...