Marking Strakes

[Sakari Aaltonen]

Building my first glued-lapstrake boat, I'm finding marking the strakes very difficult. It was easy at the first (bottom-most) lap, but up towards the sheer, the angle between successive strakes is so small that a pencil no more fits in between the existing strake and the candidate panel I wish to mark. A steel rule just does, but doesn't leave a clear mark.

How do smart people do it?

Thank you,
Sakari Aaltonen

[Mrleft8]

Try a marking knife.

[Barrett Faneuf]

I'm afraid the usual method is to use a spiling plank or trussed-together battens to make a pattern, rather than offering up an oversized plank to the boat for marking.

[Keith Wilson]

Are you using Tom Hill's method, with battens on the mold defining the plank shapes?

[Bruce Hooke]

Actually, Barrett, from what I've seen I think it's fairly common on glued-lapstrake boats to offer up the actual plank. Because the planks overlap this can be done much more effectively than on a carvel planked boat.

Like Mrleft8, my first thought was some sort of marking knife, and I still think that is worth trying, but I'm not thrilled with that solution and here's why. When you are trying to mark in a narrow cavity like that, any gap between the new plank and the previous plank can throw off your line by a lot if the pencil or knife slides down a little bit between the planks. Would it be possible to mark first from the inside, against the edge of the previous plank, and then remove the plank and measure from that line to the cut line by measuring the width of the lap? This should produce a much more reliable line because on the inside you've got a nice square edge to mark against.

If that doesn't work, another option would be to make sure the edge of the planking stock is square and then slide that steel ruler into the gap and note the reading on the ruler. Then pull the ruler out and measure that distance in from the edge of the new plank and make a mark. You can then connect your marks with a batten.

By the way, a marking knife is simply a knife with a bevel on one side only so that you can place that side flat against the edge you are using to guide the knife. While you can buy marking knives from woodworking suppliers, for one-time use you can also make one from an old jigsaw blade.

[Sakari Aaltonen]

Thank you for the suggestions, but... A marking knife is still too thick to fit in.


Originally posted by Bruce Hooke:
...... Would it be possible to mark first from the inside, against the edge of the previous plank, and then remove the plank and measure from that line to the cut line by measuring the width of the lap? This should produce a much more reliable line because on the inside you've got a nice square edge to mark against.

If that doesn't work, another option would be to make sure the edge of the planking stock is square and then slide that steel ruler into the gap and note the reading on the ruler. Then pull the ruler out and measure that distance in from the edge of the new plank and make a mark. You can then connect your marks with a batten.

Even if I could wiggle myself inside the hull to make marks from the inside, which I seriously doubt, there would be no square edges to use because of the bevelling. And the width of the bevel varies...

I think I'll just do it in two phases. First, mark and cut a strake that is wide enough to be safe, but narrow enough to allow a pencil to operate in the gap. Then, mark and cut the final strake.

Slow, yes, but I don't do this for a living, do I?

Sakari Aaltonen

[Bruce Taylor]

I'd spile the remaining planks, in the traditional way.

[Don Maurer]

When I built my boat, I cut each strake before mounting the previous one. I used the Tom Hill method, but it should also work without the stringers as long as you put a shim the thickness of the plank on the station molds at the bevel point.

[Sakari Aaltonen]

Don Maurer wrote:
When I built my boat, I cut each strake before mounting the previous one. I used the Tom Hill method, but it should also work without the stringers as long as you put a shim the thickness of the plank on the station molds at the bevel point.But doesn't this mean assuming that the previous plank will fit the station molds perfectly? If it (the plank) does, then, of course, this sounds like a great idea.

Me, I have quite a number of gaps between the planks and the molds.

Sakari Aaltonen

[ 04-23-2003, 01:47 AM: Message edited by: Sakari Aaltonen ]