Sealing up cores

[JDTOOM]

My Novi is almost entirely fiberglass except for two sheets of 3/4" marine grade plywood encased in the transom. The builder explains that this was done to strengthen the area for the outboard bracket. The cores that were used for the steering, fuel, and electrical connections to the outboard were not properly sealed (see pics). I'm looking for recommendations on how to seal the wood so there is no future deterioration.

Any help is greatly appreciated. Thanks

 

[El Mar]

Quick and dirty method is Epoxy and a rubber glove.

Smear it on the core through the hole, may want to derig if you can for better access.

I'm sure the builders on the site will have a more elegant solution.

 

[Dr Dude]

Sealing Cores

When I switched engines I had to increase the thru hulls a considerable amount. I used 5200 to seal them and to bed the new seacock as well as the
exhaust. It is a cored hull. It's been 10 years and they are dry and waterproof.
I hope this helps you.

 

[Stinkpot]

If you can get a router in there, use a bit that will allow you to router out the plywood, but not the fiberglass. Router out the plywood about 1/4" or so and then back fill this void with epoxy mixed with colloidal silica or equivalent.

If getting tools in there isn't an option, dry the wood as best as you can and then saturate with CPES.

 

[F/V First Team]

Good idea, better application:

+

=

One core removing tool not to be messed with

Gets into those hard to reach places, just have a really good grip on it. Variable speed drill is a must, and never anything with a toggle switch!

 

[Sailorgp]

On smaller holes a bent nail or cut down allen wrench can route out even a 1/4" hole...but as was mentioned in the previous post, use a variable speed drill and hold on tight. I've done this many times on balsa core...plywood would be a more difficult. On the smaller holes it's best to route out the core, completely fill the hole with thickened epoxy and then re-drill the hole through the epoxy.

 

[JDTOOM]

Thanks guys. It's my first order of business after I winterize next week. I appreciate the input and will let you know how I make out.

 

[captainlarry84]

Marine grade plywood is much heartier than any other coring. It will take a lot to get that wood soft. You can do it two ways:
#1 quick and easy is just sand it well and brush on a coating of resin.
#2 de rig (a lot of work) sand it well coat it with west systems then sleeve each hole with PVC and glue it in place with 5200 sealer. Route the edges of the PCV for a nice clean look and no sharp edges to damage any of the hose.