Rotten plywood in stern hood

LouC · **Posted:** Mon Sep 22, 2014 5:15 pm

I would just take some pix of how that material was stapled on, remove it, cut out a piece of PT wood and staple it back on. If you really want to go to town, you can use exterior ply and coat it 2-3 times with CPES, it takes a while to cure and for the smell to go away but its good stuff. WEAR a respirator not a painter's mask.

Graham....I am nostalgic for the days of carbed small block Chevrolets and therefore am sticking to that as my favored brand of marine propulsion. I would love modern outboards but I realize now that not only are they too expensive but just as vulnerable to electronic/computer glitches as modern cars. If I could find a boat with either the last of the carbed big Evinrudes or Johnsons, or a Yamaha OX66, those would be my OB of choice.
I want a power package where if it doesn't start, I replace the points n condenser. If it doesn't run right I get the carb rebuilt. Its bad enough we are stuck with these complex systems in our vehicles for sure I don't want it in my boat....

rpengr · **Posted:** Tue Sep 23, 2014 8:27 am

skidaddytn wrote:

Also you can see lots of unused holes and a few oval cuts, that were put there possibly as a drain, or because they re-purposed plywood that was previously cut for something else.

The slots would be for air vents...to allow air to escape when somebody sits on the cushion. Good to see that there is no water staining around them, so your foam must not have been soaked with water.

skidaddytn · **Joined:** Mon May 03, 2010 11:12 am **Posts:** 281

Good point on the slits being air vents, that makes sense. It will be interesting to see what condition the foam is in once I unstaple. I decided to wait until I winterize for repairs on this. I might get it apart to find out I need new foam as well... :-/ Still a good month of boating left, maybe more...

TX H210SS · **Joined:** Thu May 27, 2010 9:10 am **Posts:** 1488

I agree with your take on the fold up walk over section of the sun pad. They call it walk thru but it never gets raised for that purpose. Those hinges are knee and hoof busters for sure.

The only time I use mine it to pass the ice chest thru when loading or unloading the boat. With that said, when mine craps out I will be using pt plywood. Just remember to give that plywood time to dry out before installing. With the new environmental friendly green treatment they use in PT lumber, they stack it wet. That's why PT lumber is noticeably heavier off the rack.

Just a couple days before you seal it up with the foam so most moisture in wood has evacuated. Especially wait if you will be applying any sealer etc. Also, you can use cut pieces of inner tube as gaskets for those hinges....cheap, effective and easy.

skidaddytn · **Joined:** Mon May 03, 2010 11:12 am **Posts:** 281

Update, I finally got around to taking it all apart. The foam came off quite easily with a putty knife and is in good reusable condition. Man, were there a LOT of staples. The stitching of the vinyl once off was easier than I thought. I just did a simple back-stitch and it looks awesome again.

I'm now ready to fix the wood. Doing the job right requires buying not 1 but 2 sheets of plywood. The main layer is 1/2" plywood, but there is a 1 inch lip affixed to the perimeter which is 3/4" ply.

Black pieces of rotten wood crumbled everywhere. I certainly will not be using Marine grade plywood again based on the piece used here (which WAS apparently marine grade). I read on another site that marine grade is not necessarily designed for rot resistance, and that its more about strength. PT is weaker, but because of the chemical soak it can be more resistant to rot. Not an expert here, but based on what I see here, I think PT is probably a better choice for this location. I'll take a few more pics along the way to post here...

purdueosch · **Joined:** Mon Oct 15, 2012 9:52 am **Posts:** 141

skidaddytn wrote:

The ding dongs over at Four Winns decided it would be a good idea to use plain plywood (repeat... non-treated plywood) inside here! This is an area designed for wet people to lay on and sun-bath, put on the skis, etc... Very cheap of FW.

So are they "ding dongs" or not? I'm confused. :roll:

Just giving you hard time....

skidaddytn · **Joined:** Mon May 03, 2010 11:12 am **Posts:** 281

heh... yes, I probably need to retract that. It could be the fault of their marine plywood supplier? or maybe they should have used a different type of ply in this application. Don't know, but I have always kept the boat maintained and covered.. the failure seemed premature. Also, I'm not sure putting stitched seem designs in the vinyl here is a good idea either.. that just promotes rips, and more water seepage into the foam and wood underneath.

LouC · **Posted:** Sun Feb 01, 2015 8:01 am

Marine ply uses exterior grade glue but has no voids. It is stronger but not more rot resistant than exterior grade plywood. In that application it should have been coated with expoxy resin. Next best is PT. When Idid this job I did not have much time so I used PT. Six years later it's still OK.

Jdpber · **Posted:** Mon Feb 02, 2015 9:27 am

i am simply laying a layer of 1708 on each side of my engine/sunpad hatch. It will last longer than i have the boat lol.. toss some glass on it and be done..

skidaddytn · **Joined:** Mon May 03, 2010 11:12 am **Posts:** 281

Just remembered I forgot to post a final pic of the rebuilt wood backing. I got it installed, and everything looks great again. The PT wood does make it difficult to reattach since it is not completely flat and the bolts are just barely long enough to get the washer and nut back on... I fought with this for a while and had to use some clamps. Now that I look at this picture, maybe it wasn't the final one cause the stainless screws are not all in yet... but the pieces are cut, you get the idea.

www.iFourWinns.com

Rotten plywood in stern hood

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