Sebago Skiff caulking question

[smallboatshop]

We may have an opportunity to recondition a Sebago Skiff that's been out of the water for about 20 years. The owner remembers having to sink the boat to swell the planks when he was a kid. What would be the proper caulking and caulking method to use? The hull will be stripped of paint and any old caulking removed.

Thanks, Dan

 

[Paul Miller]

Hey Dan,

Will the boat be painted or varnished?

 

[smallboatshop]

Hi Paul,

It will be painted.

 

[Paul Miller]

The wood boat guys that restore the classic Mahogany Runabouts use 3M's 5200 which holds tight but is much more flexible than epoxy. You can just about remove the fastners once the stuff sets it's that strong a bond.

You can sand it sooth after a week of curing and then paint it.

I've never used it on a canoe as you'd see it, but have used it on boats especially those with caravel planking like the boat in the picture.

The attached is of a 1928 or 29 F.W. Conselman stepped hull race boat 14' long and 48" wide. F.W. Conselman began the Shell Lake Boat Company a year or so later.

Good luck,

Paul

 

[Todd Bradshaw]

Carvel or lapstrake planking? If it's carvel (edge-to edge planks, smooth outer surface) it probably originally had cotton calking pounded into the seams with a calking iron and a mallet. If it's lapstrake (raised ridges kind of like house siding) it may have had no calking, or maybe just something like a piece of twine soaked in tar and pinned between the planks when they were installed. You probably wouldn't be able to hammer cotton in there after the fact without damaging the planking. Ideally, it should be recalked with the same stuff and method that it originally had.

For modern gap fillers that you could substitute if keeping it original is less of a concern, I think I'd go with Lifecalk or similar polysulphide goo in tubes. 5200 is super-strong stuff, but extremely hard to remove if you ever need to fix anything or recalk.

 

[smallboatshop]

Thanks Todd and Paul
It is a carvel planked boat and looks pretty tight for being inside for 20 or so years. After looking at the youtube videos of caulking and reading up on the 3m products and sikaflex and boatlife it seems there is a lot of choice. I guess I'd be leaning toward advising the owner to go with the less permanent 3m 4000, sickaflex or boatlife. This way he can keep the boat on the trailer, ready to use without worry of leaking; and he can know that if there is a problem, the next repair man will be able to get at any problems.
If I get the job I believe I'll strip the exterior paint as much is chipped down to the cedar. Then remove the old caulking, sand the joint edges, then apply the caulking. If this is okay so far, the next question is whether to fill up the gaps with the caulking or leave an indentation for expansion. What do you think?

 

[Todd Bradshaw]

Don't know. Calking is something I've never had the chance to mess with. I can say that I used 3M 4000 to install and calk a shower stall in my house when the hardware store "lifetime" calk kept failing and it is really superb stuff and drastically better.