grp/eps/grp rigid bimini for a cruising catamaran

Hi Everyone,
First of all, sorry my english is not so good. I'l like to know if somebody could say if it's a good idea to buidl a rigid bimini in the way of a sandwich GRP/EPS/GRP. Dimensions should be about 3.3m x 1.5m with only two pillars each side of the cokpit. You can see pictures of the cat at www.citoyendumonde.unblog.fr . The choice of eps is because it's impossible to find PVC foam in my contry. New Caledonia. Shipping, custom (expensive product as well) costs are very expensive to my far far away country. In an other hand I can easily find EPS as it is commonly used in house building market.
Many thanks

Philippe.

 

Oups, I'm wrong. I know polyester resins and polystyrene can't go together. I meant Glass reinforced epoxy/ expanded polystyrene/glass reinforced epoxy so GRE/EPS/GRE sandwich.

 

No

Hello Philippe

You should not use EPS foam at all. It is too weak. The job of a sandwich core is to take shear loads and this foam won't. I would suggest using a light timber. Ask around and see if you have any timber like Paulownia or Western Red cedar. Something less than 380gm/metre cubed is good. Strip these up into 15-20mm thicknesses and they will make a strong and light top with 600 double bias top and bottom.

I have tried polystyrene foam myself and it did not work. I just had to remake the part.

I guess you have tried ATL and FGI in Australia. Strangely enough you could get them to cut the foam into pieces that are easy to ship. Say 120cm x 20cm. Then when you get it you just stick it back together on a piece of plastic covered ply or melamine. Foam does not care if it is made from lots of pieces.

Alternatively it gives you a good excuse to come over to Australia and see the reef and build the top.

cheers

Phil

 

Hello Phil,
Thank you very much for your valuable advices. Coming to Australia, of course, I would love. Ive been there many times on holidays. I have been learning English for six mounths at Bond University QLD as well in 2002 . I also went in Brisbane in 2008 for a sea trial on QUEENSLANDER, a GBE catamaran I intended to buy. But I didn't. I'm going to google ATL and FGI to get in touch with them.

Many thanks again.

Philippe.