How to Cotton-Caulk Boats
Caulking seals the seams between the planks of wooden vessels. Introducing cotton caulking into the seams of wooden boats requires several tools, including a short-handled wooden mallet and a set of "irons" that look like chisels. Most of the irons have ends that are flattened or, in the case of the hardening iron, grooved on the end that fits over the cotton twine as it rests in the seam. Finally, there's a two-handled hook, called a raking iron, that's used to remove the old caulk. These tools can be found at traditional boat supply houses or ship chandlers.
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Things You'll Need
- Raking iron
- Dumb iron
- Wooden mallet
- Cotton marline
- Well-sharpened jackknife
- Making iron
- Hardening iron
- Tar
- Putty knife
- Bent iron
Instructions
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1
Pull the two-handled raking iron through the seam between planks to remove the old caulking. Take care that the hook on its end doesn't damage the edges of the planks. Where seams are too tight for the raking iron, use the dumb iron to open the seam enough to access the old caulking, then use the raking iron to remove the caulk.
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2
Tap the top of the wide-blade dumb iron with the wooden mallet to set it between the planks, spreading them in the process. Use the dumb iron only if the seam between planks is too small to accept the raking iron. The deeper you set the dumb iron, the more you widen the seam. If the seam is wide enough for the raking iron, it's large enough for the marline caulking.
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3
Set the cotton marline over the top of the seam. Marline is cotton twine soaked in tar and caulking was one of its many uses aboard ships during the 1700s. Hence the phrase "Jack Tar" was used to describe a seaman during that time. Marline comes in a ball, like other twine, and you can cut it to length with a sharp jackknife.
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4
Set the wide, flat end of the making iron over the marline. Tap the top of the making iron to push the marline into the seam until the marline is level with one of the adjacent deck planks.
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5
Place the grooved end of the hardening iron over the marline as it rests in the seam at deck level. Tap the top of the iron to drive the marline into the seam for a distance equal to its own thickness.
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6
Fill the seam with tar and scrape any tar from the exposed surface of the deck planking with a putty knife; neatness counts.
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Tips & Warnings
Start laying caulk in the corners.
For corners and other hard-to-reach places, use a bent iron to tap the caulk into place.
