Questions on replacing plywood under sunpad/engine cover

bthessel

Cadet
Joined
Jun 21, 2010
Messages
22
A couple of questions. It looks like the plywood was replaced once before on my 97 Maxum. It is rotted and busted out again and I am going to replace it. Right now the underside has carpet on it as you can see in the pictures, I am worried that is causing it to rot faster since water get's trapped under it, should I put it back on? Also the shocks don't seem to help at all in lifting the back and don't seem to hold it up at all. The seem to have pretty good pressure now that I have them off though. Should they be mounted so close to the back of the cover? it seems like they wouldn't have much leverage there.

Photo-5_7_12-8.30.46-PM-1.jpgPhoto-5_7_12-8.30.46-PM-3.jpg
 

oops!

Supreme Mariner
Joined
Oct 18, 2007
Messages
12,932
Re: Questions on replacing plywood under sunpad/engine cover

there are only a few possibilities for that deck rotting constantly.

the foam under the vynal is wet due to seepage from the sewing on the pad.

the pad is left uncovered and the rain water is collecting around the edge of the piping and the pad well.

the rug on the under side is constantly wet.....(this is unlikely due to the fact it is normally up side down.


the remedies are......use pressure treated wood.....and paint it.
(you could also glass the wood)
also make sure that the foam is wrapped in a plastic bag....

you can use a different type of under cover instead of the carpet if you wish......but the carpet is sound proofing for the motor.

as for the shocks......chances are they are worn.....repace them if you can.....but moving the bases far from the hinge will help
 

bthessel

Cadet
Joined
Jun 21, 2010
Messages
22
Re: Questions on replacing plywood under sunpad/engine cover

there are only a few possibilities for that deck rotting constantly.

the foam under the vynal is wet due to seepage from the sewing on the pad.

the pad is left uncovered and the rain water is collecting around the edge of the piping and the pad well.

the rug on the under side is constantly wet.....(this is unlikely due to the fact it is normally up side down.


the remedies are......use pressure treated wood.....and paint it.
(you could also glass the wood)
also make sure that the foam is wrapped in a plastic bag....

you can use a different type of under cover instead of the carpet if you wish......but the carpet is sound proofing for the motor.

as for the shocks......chances are they are worn.....repace them if you can.....but moving the bases far from the hinge will help

The foam under the vinyl is not wrapped at all and most of the rot is along the back edge so I am guessing it is just seepage from people climbing in and out. I never leave the boat uncovered outside and it is stored inside during the winter but I have only had it for 2 1/2 years. It was already starting to show some weakness right when I bought it.


Thanks for the advice!
 

britisher

Petty Officer 1st Class
Joined
Feb 23, 2012
Messages
369
Re: Questions on replacing plywood under sunpad/engine cover

I sympathize mate. I have a SeaRay 180 which I'm refurbishing. All my wood is rotten. My layout is similar to yours with a full width plywood sunpad/engine cover. The vinyl has cracked over time with being walked on and I too noticed the foam isn't wrapped. Also my ply seems to have been pressure treated, but that's all. It has filets along the back and for the padded backrest and at the back for the hinges. They too are all shot. You could do worse than replace the ply but glass it in with resin and csm. Maybe some higher spec fiberglass such as 1708. Either way, it has to be better than nothing. My pad has a low tech pole to hold it up and I was thinking of upgrading to gas struts, but I look at the thickness of the ply (3/4") and wonder whether that isn't overkill. Maybe a thinner (5/8") ply with some wood or aluminum bracing underneath would make it lighter, but stronger. Just my 5 cents worth.
 

havoc_squad

Senior Chief Petty Officer
Joined
Mar 5, 2011
Messages
693
Re: Questions on replacing plywood under sunpad/engine cover

I recommend that you at least put a thick coat of durable latex paint over the replacement wood on the top. That will do a bare adaquate job of water resisting if you fear fiberglassing.

My recommendation is you do a single layer of chopped strand mat fiberglass over it on the top and the sides of the wood that will replace it.

Having the chopped strand mat cover the side edges of the plywood is not a big deal. However, sealing the edges with sufficient polyester resin and coat a very small portion of the underside from the edge. 1/2 is perfectly fine.

However, do NOT go overboard on too much csm or resin, otherwise it will be REALLY heavy and the shocks holding the board up will struggle or fail. Fiberglass it good enough to get 1 layer down and properly coated.

If you drill or add screws into the board, do that first and get it well fitted before fiberglassing. You do not want any holes that are not sealed, nor do you want any exposed holes on the top.

Re-covering it and fitting it is a little bit more involved than rebuilding a removable deck gas tank cover for a boat floor, but very close to the same concepts for making it sturdy and shedding water well.
 
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