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-   -   Sailboat bulkhead material and Location (http://www.sailnet.com/forums/sailboat-design-construction/42863-sailboat-bulkhead-material-location.html)

jbibb 05-05-2008 12:58 PM

Sailboat bulkhead material and Location
 
I'm really using this forum to gear up for a project, thank you very much.

Marine plywood versus standard pressure treated plywood as an alternative for a bulkhead material? Marine plywood needs to be shipped in from Seattle...I can grab a sheet of 3/4" pressure treated right off of the shelf. Any issues with this that folks can comment on?

Follow up, I've been reading about some folks using a fiberglass G-10 panels in a West System write-up as well for an alternative.

Also, Location....is there any reason not to remove a bulkhead while the boat is in the water....structurally or is this a boatyard repair. I can shore up the lateral as required, however without load...mast removed and shrouds not connected, cabin deck supported internally...is there a flex issue with the boat simply floating without a main bulkhead?

dakuehn 05-05-2008 01:38 PM

I replaced my starboard side bulkhead recently and used marine plywood because I had ready access to it for a fair price. In retrospect, I am not sure it was necessary because I ended up coating the piece with epoxy and strengthing areas with additional layers of fabric. The marine ply is clearly superior to the standard and I have a greater level of confidence in the repair. Also my boat is 7.3 meter and will not have the same load as your Cal. West Systems Epoxy Works had a good article on a bulkhead repair where an even more $$ and exotic material was used

jbibb 05-05-2008 01:43 PM

Yes, I read that article and looked at the composite board material! $$ is right....but bulletproof. Thanks.

sailingdog 05-05-2008 04:55 PM

Jbibb-

You are aware that pressure treated woods, including pressure treated plywood, are fairly toxic, since they are basically saturated with toxic heavy metal poisons as a preservative technique. Using them on the interior of a sailboat is probably not a great idea, and if you are going to work with them, wear a very good dust mask, as the dust is rather nastier than what normal marine plywood would create, having arsenic-related compounds in it IIRC. :)

jbibb 05-06-2008 01:38 AM

Thanks Sailingdog. Great point on the toxicity. I was thinking simply on durability and not that I'd have to be living next to it.

Stillraining 05-06-2008 01:57 AM

Marine plywood has a couple advantages ...extra ply and no voids..been told same glue is in exterior ply so thats no better...but for a bulkhead that will be reinforced anyway I would not pay special fright and or wait for it to arrive just to have it but would go with 3/4 inch cc plugged ex tier...

Pressure treated ply also is not as stiff due to the impregnation process...it warps a lot easier under loads...so I would not use it for a bulk head...I wish Bayliner would have used it for transoms in their boats though...they would not have such a rot issue...

You will be fine pulling your main bulk head under the conditions you listed still in the water...

Lion35 05-06-2008 12:12 PM

My feeling on these type of questions is that the labor of the job (your time)is exponentially more expensive than the materials and often you are short changing yourself by choosing a less expensive material over the one you know is better. Just my two cents but I have found that after spending 80 or so hours (WAG) on a job like this it's easy to regret saving $50-75 or so bucks for cheaper materials.

Good marine plywood cuts much cleaner, the plys are usually finer grain, is vastly stiffer as Stillraing points out, has no voids, and will provide the right answer for the next potential owners survey.

Whichever way you go, good luck with the project

feetup 05-06-2008 12:31 PM

I can understand the difficulty you face, if the proper material is not available. Would your supplier be willing to put a few sheets of marine ply on his next shipment of material, and perhaps split the freight with you?
Whatever you use, I would echo the others and say use the best you can get your hands on. It isn't an easy job to begin with, and it would be a shame to see first class labor with second rate materials.
From my own expierience I would advise that once the piece is cut and test fit that you seal all the edges with thickened epoxy, two coats is best, and then tab to the hull well. Your bulkheads may never have rotted if the edges were sealed well. Wooden boats can funcion well indefinately with water inside, but plywood fairs poorly to being even damp for long periods.

Do the job well and be pleased with the result.

Feetup

jbibb 05-06-2008 12:54 PM

Great stuff guys....thank you very much. Marine Ply it is an take my time.


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