mikiek

Chuck - for measuring the frame edges the best method is also the hardest. You'll need to mark where the top edge of the upper most plank will be. Do this on each frame. Then mark where the bottom edge of the bottom most plank will be. This might be a frame or it could be deadwood depending on your build and where the bands end.

Next you need to measure the between the upper and lower mark on each frame. I take a piece of string, put one end on the frame edge at your top mark then run the string down, following the edge, to the lower mark. Do something to notate the bottom spot on the string. Then take the string and stretch it out and measure the distance. Do this for each frame. Note doing this eliminates some (but not all) of the curvature error. Someone the other day used tape instead of string to do this. That might be a good idea just make sure whatever you use stays flush with the frame edge. It's important to get an accurate read for this.

Once you have the total distance for each frame edge, divide that number by the number of bands and you get the width of a band for each frame. If you used tape, you can mark the bands on the tape, put the tape back on the frame edges and then mark the edges. What you want to end up with is something like this

Hello Chuck - I use the dividers for hull planking. If you are fortunate enough to get a hull plan with your kit (I assume you are a kit builder) there should be some bands drawn out. Most builds will have from 3 - 8 bands. If you can get the bands marked on your frame edges there is a lot less work involved.

If you have to figure out bands on your own - and I do recommend using them - it's a different matter. Some measuring and calculating you will have to do. If you need info on that let me know.

You are correct mentioning curvature on the frames. Dividers were intended mainly for working on flat surfaces. What that means is you may end up with a little extra space to fill with planks. It's an acceptable margin of error to me. For instance on my current build I had somewhere between 1/32" and 1/16". 

The good news is if you remeasure your remaining space (with the divs) in the band after each strake it will usually correct itself. But that is the key. After each strake is laid and before you start the next one, remeasure the remaining space on the band on each frame. The dividers will adjust accordingly.

As far as deadwood, if there is a band on it then yes you can use the dividers on it. The only time that gets messy is when your band has both deadwood and part of a frame in it. But even there the principle is the same.

One last thing. You can always recalculate your bands even in the middle of planking. For instance on my current build I started with 4 bands. I laid the garboard and the 2 strakes above that first off. This filled the bottom band about half way. Then I moved to the upper bands. I did the top one and the  one under that. I think some of that curvature hit me as the last strake in the 2nd band did not quite hit the band marks. I was off by that 1/32". At that point I decided to combine the remaining space and call it 1 band. Of course I had to recalculate how many strakes in the band but the calculation worked out. Today I laid the last 2 strakes and they both fit perfectly.

Hope that helps.....