Making a spline...

[NGrace]

Is there a book that explains the process of making a spline to patch or fill a crack in a plank? I have an old dory that has some stress cracks and would like to fill these so that the crack stops, and the plank is water tight in that area. The rest of the plank is fine.

Thanks for any insight and advice.

Nate

[pipefitter]

Are you sure the cracks don't close up when the boat is wet? Is the boat wet now?From what I have read and seen,splines are used on the edges of planks to make up for shrunken or tired seams that wont swell shut properly or enough to hold good caulking.If you could show some pictures so that some others here could see what you mean by stress cracks and where they are located on the plank such as edges or on the face of,would be of more help.

[Joe Lambert]

We've come across similar problems on a Hershoff Columbia Dory. The cracks would be in excess of 1/4 inch wide when the boat had dried out but after a week of swelling they would be invisible. If you do fix a crack when the boat is dried out you can very easily buckle the plank when things get wet.

If you really do need to put in some material I'd recomend using a full thickness dutchman the length of the crack. I think Wooden boat had a diagram for a router jig a few months back that makes this much easier.

Good luck

[NGrace]

Thanks for the info. The boat is currently dry, has been for about a month or so now, and yes the cracks have opened up a bit. You can see daylight through one of them. The did appear to be tight when the boat was wet. If not a spline to fill the void, how about a flexible adhesive filler of some kind? Would it also be wise to drill holes at the ends of the cracks and fill with some sort of wooden plug, to prevent the crack from progressing any further?

Thanks for the help. I've fixed up a few boats in the past, but this is by far the biggest undertaking for me to date.

Regards,
Nate Grace

[George Ray]

A Pete Culler "Goops and Goos" old fashioned cure for big crack is a mixture of beeswax and tallow. It can be made thicker or thinner depending on the crack by adjusting the proportions of beeswax and tallow. For deep cracks in keels/deadwood it can be put into an automotive grease gun and then a hole drilled through good wood into the middle of the crack and a grease fitting (zerk) screwed into the hole in the wood and hole and crack pumped full of this stuff.

If the boat were dryed out this would not be a problem as the goop would squeeze as needed to adjust the pressure. Unlike a spline or a thick bodied firm setting compound that would force the split to open further as the wood tried to swell shut but could not because someone had jammed something in the crack. That has killed a few boats.