I have heard of several different ways to caulk a heavy wooden boat, what are your best suggestions? My idea at the moment (Taken from an ‘aged’ shipwrights book) is to use heavy, heated tar which would be soaked into the caulking cotton and that hammered into the seam. Then a linseed oil putty on top to bring it up the the plank level for sanding. What are your thoughts on that method? Thank you in advance.
That is the only way to do it right. I was shown by a guy at a boatyard.
It is dirty, nasty and on your knees painstaking work.
Ask the Skipper and Gilligan. They should know.
Hi your info is mostly correct I used to own a 40ft wood boat
and had to caulk it quite a few times, the only thing i would do
extra to your list is to every 1inch as you put the cotton in put
a twist in the cotton ( just a loop ) this was shown to me by an
old shipwright, this stops it pulling out to easy. By the way
insted of useing tar there is a much cleaner way useing a tube
of synthetic sealant like 3M 5200. If yours is a boat with large
planks do not use cotton but use hemp it is better .
It is not ‘dirty’. It is not ‘nasty’. It is not ‘painstaking’: It is one of the loveliest and most ‘touchy-feely’ tasks a shipwright ever does!
When you get it right the hammer ’sings’ on the iron, and the iron on the hull and you hear its response: and you Know it is right.
And the whole hull sings as well! As you progress, the very note increases: up and up! (You need a good ‘ear’ for music – It must not be allowed to develop into a big ‘thud’!)
(No leaks on the launch and no split planks after the launch – from being over-zealous – that’s the objective. )
There is a lot to it:
Choose the number of threads (for each-and-every inch of each-and-every seam – they are all different). Wind them in a hand-drill. Put them into a cardboard box. Take them to the vessel. Loop them (by hand and iron) into the appropriate seam. Hammer them in. Harden them up (Iron 2).
Pay-up, paint, antifoul and launch.
. . . Then, Hold Your Breath!
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