A reader writes: This photo of my newly purchased second-hand boat shows some of the exposed plywood end-grain on a fitting down below. The boat is only a couple of years old and although the wood is in really good condition, I worry that this exposed raw wood is going to soak up water and start delaminating, staining the top finished veneer. What do you recommend to help minimise the chance of this occurring?

Exposed end-grain

In the marine environment, unsealed plywood end-grain will eventually pick up moisture and start to delaminate. Best to seal it with epoxy before that happens.

Ed Sherman answers: Whether or not end-grain is sealed is something I always regard as a quality indicator when I inspect new boats. Truth is, though, most production boats don’t seal it, just as you show on your boat.

The best fix for this is to use an enhanced epoxy, painted onto the end-grain, which must be allowed to fully cure before putting things back together. When I say enhanced, I’m referring to a regular epoxy/hardener mix, with an additional additive that will need to be stirred into the epoxy to make it more resistant to eventual water penetration.

West System, for example, offers their #422 barrier coat additive. Most of these additives consist of microscopic 'platelets' that sort of lie flat and create an additional barrier as water tries to penetrate the coating. Although originally intended to be used on the outside of a boat’s hull to prevent gelcoat osmotic blistering, the 422 will also give your woodwork years of maintenance-free protection.

The additive will turn the epoxy light grey, but that shouldn’t matter, as those surfaces will remain mostly hidden when things are reassembled. The platelets also add a bit of abrasion-resistance to the epoxy coating, which isn’t a bad thing here as these parts may in fact be rubbing together once reassembled.

If this has got you wondering what else you could be getting on with during the winter months, click here for a full list of boat maintenance features. Or for the quick version, try Rupert Holmes' 5 Top Winter Yacht Projects or How to maintain your boat.

Written by: Ed Sherman
Ed Sherman is a regular contributor to boats.com, as well as to Professional Boatbuilder and Cruising World, where he previously was electronics editor. He also is the curriculum director for the American Boat and Yacht Council. Previously, Ed was chairman of the Marine Technology Department at the New England Institute of Technology. Ed’s blog posts appear courtesy of his website, EdsBoatTips.