View Full Version : External under-paint semi-flexiable hull sealer?

12-07-2011, 02:18 PM
I am painting the free-board on my boat. I wanted to know of a good long lasting product that can patch up the seams on the planking. I figure this is a part of the boat that may flex from time to time so I am thinking a hard epoxy may not be the best solution. This would be for the external part of the hull only. The hull actually keeps water out quite nicely. It is basically to spackle any of the seams before the paint is brushed. Strip-planked hull.

Related posting to the work being done: I will be using epoxy here.
Thank you.

Ian McColgin
12-07-2011, 02:45 PM
What you are calling the freeboard is more normally called the topsides. The other part of the hull is the bottom. Freeboard is the height of the gunnel above water, same as the height of the topsides.

I glanced at the other thread and am not at all sure you're on the right track. An older iron fastened hull with bleeding fastenings can last and last before refastening is absolutely mandatory but - I've had a number of older iron fastened boats - the rust will bleed past anything. You're better off finding a color like ultra dark green that simply hides the rust.

There is no covering for lousy seams that makes any sense on a wooden boat. You'll just make rot. To fix the seams, fix the seams. You probably don't have to get all the fibre caulking out, but clean out the compound and redo that with a nice topsides seam compound. NOT SitkaFlex or 5200 of LifeCaulk - real seam compound. There's topsides seam compound, always white, and underwater (for the bottom) seam compound that's brown. You can trowel it in but it's faster and neater to load the stuff into a greasegun you've adapted and inject into the seam, trowling and smoothing as you go.

Then paint with a normal oil paint that can move with the boat. The wonderful modern plastics are too pricey to waste on something that will bleed through from the rust and will be brittle enough to crack along the seams.


Bob Cleek
12-07-2011, 02:46 PM
A strip planked hull shouldn't "flex" at all. If the seams are at all deep (more than 1/8"), then use Interlux TOPSIDE seam compound. (Use Interlux UNDERWATER seam compound for below the waterline.) If they are really shallow, use Interlux surfacing putty (sometimes called "glazing compound".) You just apply with a putty knife and sand smooth. This is also used to fill small dings and scratches and such.