Question on building types..Weight vs Strength

[Bronn]

Hey all,

Posted something similar in boat design but i actually am looking for an answer to more specific questions which are below.

I'm looking to build a powered catamaran (I now have the plan design picked out) but am looking to build the boat as light as possible with keeping the same strengths.

The boat is designed as a wood build all penetrated with epoxy and the outside of the 3/8" marine plywood hull laminated with single layer fiberglass...then coats of epoxy. Bulkhead joints to hull and hull seams all reinforced with layered fiberglass. The cabin and decks etc. are made of the same construction. It is a powered catamaran 24' length / 8'-6" wide, 2 outboards each at 130 hp, finished weight in wood 2500lbs.

So my question is, in terms of weight keeping with the same strength but possibly going lighter:

- Is a sandwiched foam core lighter to keep the same strength for the hull? Or keep the hull as designed but possibly supplement balsa for everything topdeck? Which hull designs are the lightest keeping with the same strength as the above is designed?

I appreciate any help.

[northerncat]

out of curiousity where did you find the plans?
sean

[Petros]

Optimizing weight for different construction methods is a lot of work and may only save 10-15% of hull weight. That is assuming the current design is optimized. All foam and fiberglass construction actually cost more to build as well.

You might find you can save more weight by stripping off all non-essential features or accessories, and lightening up all non-structural components.

You also might consider looking into Durakore panels. These are hardwood verniers with balsa core panels that are used much like plywood. I think on their website there is software or rules to develop the right combination of thickness and layup to get the best strength.

Good luck.

[Bronn]

Sorry been away from my computer.

The boat i have decided to build will be a Glen-L design. Its the 24ft powered catamaran cubby called Wildcat EXT Cubby. It has my favorite lines and i will be building the cabin to suit me. Im very excited having finally picked out which boat i want to build. Construction won't start for at least a year as i need to build my house and workshop first hehe. I can't wait.

Thank you Petros for a look at those cores. Seems a defininate possibly i can use without completely changing the all wood design of the Wildcat.