Plank width

[JimM]

Hi
I have read a number of books on boat building and I understand the process of spiling with a temporary batten to find the shape of a carvel plank. What I haven't figured out is how do you figure out when you order wood how wide a plank you need.

Jim McGee

[Art Read]

Not to be "flippant", but more than you think you need. Unless your supplier is awfully flexible, no matter how carefully you plan, you'll probably have to settle for odd widths and lengths. That actually works out pretty well though. If your project isn't small enough that you can hope to get your planks out full length, you'll likely find yourself endlessly picking through the stock you DO get, looking for just the right pieces to scarph together into the full sized planks anyway. It will help if you have at least a general idea of what your maximum plank widths will be, but remember, they all curve along their lengths once bent over the frames, so you can never get wide enough stock.

One time consuming, but illuminating, technique is to make up some rough "patterns" of every plank on one side of the hull out of cheap "doorskin" plywood to give yourself a "feel" for the two dimensional shape of your three dimensional planks.

Hope this helps...

(Here's a picture of how I used my own "patterns" to measure for suitable planking stock.)

http://www.imagestation.com/picture/sraid15/p1bce7594ea8d9ed9eb005463d384ceec/fdebc431.jpg

[ 01-26-2003, 01:42 AM: Message edited by: Art Read ]

[Mr.O]

Jim: Seeing that you're in Wenatchee you really aren't too far from some excellent sources of cedar planking material. If thats what you're using/looking for. Its hard to tell the width of pkanks right off unless you've built the boat before or some one specifys the sizes in the plans. Personally I'm building a Haven 12 1/2. When I initially started I had the same question. How wide are each of the planks? Well when I got into the process of planking I used door skins to find the sizes and it worked quite well. The good thing was that I found a source of clear cedar at the end of Kootany Lake B.C. I initially got a bunch of planks 18' long (Haven is 16' long) 18" wide. Then later went back for more. This time 18' long and 10" wide. Didn't need that 18" wide material this time. I don't mean to sound like cedar iis sitting up there just waiting for us to buy it. I had to wait and be patient but its up there and its great stuff. Hope this helps. Jack

[Art Read]

Didn't notice you were a neighbor, Jim! If Jack's suggestion doesn't pan out for you, and if you're interested in some nice, but recycled, old growth, Port Orford Cedar, I know a source out in Port Townsend from a boatbuilder/part time wood sawer who can also offer some pretty good "hand holding" with wood selection/sizing, etc. That's where my planking came from and though it wasn't exactly "cheap", and there were some defects to work around, (it came from an eighty year old bridge after all!) I've been very happy with it.

[Paul Scheuer]

There's probably a way to do it mathmatically, but I think Art's door-skin pattern is more direct. My experience with 4 inches of the shear of my Snipe project was that it would have taken at least an 8 inch board to do the curve. Once I had the pattern, I used it to plan the dog leg scarph in the stock. I used some 1/8 inch leftover cedar lumber from a previous re-sawing project.

If nothing else, you want measurements taken from a baseline on a piece that's laying flat on the frames.

Or maybe there's a clue from the removed piece.

[JimM]

Art, Jack and Paul
Thank you for your responce. I guess I will have to wait till I buy plans and see if the designer provides a list of material. I still haven't decided what to build. I have one more question. Are a pattern made with door skins strong enough to use as a pattern on a router table?
Jim McGee

[ 01-28-2003, 12:21 PM: Message edited by: JimM ]

[Walcheren]

When I built the Catspaw I ran into the same question and problem. I had ordered 6" planks thinking that would be ample. But once I started planking the truth came out and in the centre of the boat I could not get the width required. In fact I ended up edgegluing the piece I cut of one side to the other side of the same board which resulted in a board that approximated the shape required. For the Poulsbo I ordered 8" planks, 16feet clear cedar. Rembering the Catspaw experience and getting in real trouble when I wanted to put the shear planks on to start with, wasting two planks, I decided I put the garboard on. Then the rub strake. Then I measured at each frame the distance between the garboard and the rubstrake and devided that by 10. That worked out at just under 4" in the middle where the greatest width is. So now I split my 8" boards in half, marked the frame distances and the required width at each frame.(leaving the side of plank straight where I measured the width from) Took a spiling batten and drew the curve, cut the plank out, planed the edges, steamed her and put her on. This worked every time. The shearplank I cut in half as there was no way I could get that plank in while 4" wide. So I put on two 2" boards edge to edge, no caulking, just a bit of putty and now painted you can't see a thing. It's a long story but I thought I should tell because I found this last technique worked so well. And the lines of the plank look very good, run in very nice curves. This was the issue I was most uncertain and baffled about.