The Boating Forum - Contemplating making a fiberglass storage seat- any advice?

I'm planning on building a 20"W x 20"D x24" tall storage compartment /seat to replace the pedestal captain's seat. We've gotten tired of either having tackle boxes on the deck or having to go in the cuddy to retrieve stuff. My question to all of the fiberglass gurus out there is : How thick do I have to go with fiberglass alone to make the box strong enough to sit on with regularity? I wouldn't worry so much if it was completely enclosed but the plan is to make one side (the side facing the stern) open with shelves for Plano boxes/ storage bins and a door. I thought about building a wood frame but I hate the idea of putting wood on the boat even if I glassed it in.

BTW: planning on using epoxy resin.

Second question: I am still debating whether to use cloth or woven roving. I have only ever used cloth and chopped mat in the past. I've been told that woven roving is stronger for straight sided applications. Any advice?

I can't advise you on fiberglass construction and it doesn't look like anyone is going to either so how about this:

I've seen many premade seat/storage combinations in catalogs, on websites, etc. If you can find something that fits your needs, you will be way ahead of the game. Just buy it and install it. Even if you have to modify it.

I would make it out of very thin plywood and then glass it.

There are many products out there ready made that might work for you, as Rwidman suggests, but this is a decent DIY project because its pretty straightforward not too hard to accomplish. To answer your questions, if I were to build something like this I would build a quick mold and lay up 1.5 oz mat-4mm Coremat-1.5 oz mat+24 oz woven roving with polyester resin. There are many materials and methods available to you but I think this would give you a good combination of strength and stiffness. Some materials, like epoxy, are just overkill for this type of thing.

What level of finish are you looking to achieve? I can point you in the right direction if you want to proceed with building one.

You may want to consider Starboard instaed of glass. May cost more but it's easier to work with.

I would make it out of very thin plywood and then glass it.

What he said. You can use exterier grade 1/4 or 5mm luan. Make the box, glass it with 17/08 and epoxy. Coat the bare wood with a couple coats of epoxy and let it soak in for our or 2 before adding the glass/epoxy. Luan is real dry and will soak up the resin out of the glass if not coated 1st.

There is always this desire to make a project out of something that cannot rot, but I have seen tables with exterior plywood and a coat of paint that have stood up for 20 years in the weather and are still going strong.

That being said, my brother made a very nice seat/box out of plywood (with a finished side) for is master angler. His is fancy with dove tail joints and what not. He then stained it then added a couple layers of poly. very nice and easy. His took a while to plan and, not having a professional wood shop, the dove tailing and fitting took a little time but it came out very nice.

Personally I thing wood adds character in certain circumstances.

If nothing else, I brought the thread back to life! ;)

If you're going to sit on it or mount a seat on it, you can reinforce the four corners and the top. The rest is just for looks and to keep it from racking. Think of an ordinary chair with the legs closed in.

I just created a water tight deck/storage area on a fiberglass jon boat. I used a good quality 1/2" ply and glassed it on both sides before glassing it to the boat itself. Trust me, do it right and you will not have to worry about the fact that there is wood on your boat for a very long time if ever. Starboard is not a bad idea but, nothing will really glue it so you would have to get pretty thick board to screw it together and, starboard is not as rigid/stable as glassed plywood would be. Just my .02 worth. Good luck.