A Shipwright in Training

It really helps to have a certain amount of OCD when doing this work. Not all the time, granted, but when you’re getting set for planking, you bet. Case in point: fitting the wedges.

In this photo you see that the frames go beneath the keel. The planks ride on the frames, but the astute boatbuilder will notice that the rabbet is up there above where the frame goes beneath the keel. Now, the garboard plank goes into the rabbet… how does it get from the frame up to the rabbet? Why, with a wedge of course. We’ll get to that in a second. The other thing you’re probably dying to yell out of course is, What About The Angle Of The Base of the Rabbet??!! Good question. Let’s look at that one.

You’ll see that when the plank comes up from the frame and meets the base of the rabbet, the plank is at a slight angle, but the rabbet base (made up of the plane defined by the bearding line and apex) is flat. If the plank rests on this flat base, it will only touch at the outer edge. Observe:

See, you knew that wasn’t right, and you were correct. A bad boatbuilder will fill this space with 5200 and hope that no one was looking. We are good boatbuilders, so we fix the angle. Just to give you an idea of scale here, the gap between the fid (the little block of wood I’m using to determine the plank angle) and the apex (the inner corner of the rabbet) is about 1/32nd of an inch. It’s HUGE.

So, a little planing later, and we get this:

Much better. That gap has been reduced to about 1/128th and it’s only right at the apex. The plank now has lots of solid wood to support it and keep it from moving. Moving planks are invitations to water infiltration.

Now, just do this with every single frame along the length of the boat, and then connect all those little bevel corrections into one long smooth slightly rolling bevel and you pass your good boatbuilder test.

Once you’ve done that, it’s time to add the wedges. You’d be the laughing stock of the boatbuilder world if you just figured you’d let your plank span the distance from the frame to the rabbet without some kind of support. And they would be right to mock you. So, to preserve your dignity, you add a little wedge between the frame and the rabbet. Once you do this, you again take your trusty fid, and make sure that you’ve got that same wonderful fit as before. If not, you plane down your wedge to acheive said fit. You glue your wedge on with hot glue. A screw from the plank will later hold it in place permanently. Here’s Kevin adding wedges to his side of the boat. I’ve added mine already. The ones that are light colored have been planed to fit the newly beveled rabbet.

Here’s a wedge being tested with the fid. It’s a pretty good fit.

You’ll also notice that we leave the wedges 3/8ths of an inch away from the keel. Of course you noticed that, I know. This allows water in the bottom of the boat to flow to the lowest point of the boat where you can siphon it away some day. They’re called Limber Holes.
Once you’ve faired the rabbet this way, it’s time to fair all your nice little wedges and then fair the whole sheebang into the stem rabbet.
Fair fair fair. The result is people look at your boat and say things like, “what sweet lines she has, cap’n!”
You fair up a boat with battens. Here I am putting a batten along the frames and wedges and hooking it into the stem rabbet.

The whole point of this exercise is to check just how well all your frames, wedges, and rabbet bases lie fair. If everything is accurate and fair, the batten will just exactly lie across each member. Just like your plank should, by the way. If the plank lies across everything all nice and neat, then it’s well supported along its length in a smooth, fair curve.
Once again, 1/32nd of an inch is HUGE. You find that, and you plane, chisel, spokeshave, scrape, or otherwise remove Very Tinnnnnyyyyyy bits of wood, and check again. It’s all about sneaking up on the point where your batten just lies on the members. OCD is good here.

In this pic you can see the batten touches the rightmost frame, is just above the frame to its left, as well as the light colored mold to the left of that. It just barely touches the left side of the leftmost frame. This means that the frame to the left (and the one to the left of that) are a tiny bit high and need some planing down… maybe 1/64th of an inch or so. That’s about the width of two letter i’s on your screen.

In this picture, Kevin has clamped a long batten along his wedges to see if any of them are high or low. He’ll then fair them down, adjust the rabbet if he needs to, until everything flows sweetly into everything else.

It’s this kind of detail that keeps your cheese dry in the boat when you’re out trying to impress some cute thing with your suave and sailorly ways.

This entry was posted on Monday, November 20th, 2006 at 8:28 pm and is filed under Classes. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.