View Full Version : Lining off a 13 1/2 foot Barto Melonseed
03-23-2006, 09:47 PM
I'm having "fun" trying to figure out plank widths as I line off this hull, given that the garboard's width is quite variable from station to station. If anyone has actually built this boat, or has one they can send me some measurements from, I'd love to send a few e-mails back and forth on this topic.
03-26-2006, 12:30 PM
The following is, in a nut shell, the way I lined off the 16' version of the melonseed. This version called for seven planks. I first figured out the shape of the rubrail and marked it off on the molds where it will be positioned. (I actually built the rails first knowing that their shape would be tappered at both ends and not easily guessed at without having their true shape.) I used these marks as the new shear line for lining off purposes. I then measured the length of the transom and the widest (center) mold. I also measured the height of the stem from the "new" shear to the top of the chine. I divided these measurements by seven and marked them on the stem and the transom. (Do this on the transom and stem themselves and not the nearset molds to get the most accurate plank end widths.) This insures that the plank ends will be close to the same width which is important visually. Since the melonseed has a wide bottom before the turn of the bilge, I wanted to take up more of this space with the first three boards. I added an inch or so to the garboards' and the broadstrakes' dimensions on the center mold and about a half of an inch to the third plank. I marked these plank lands on the molds. I then wanted to make the four remaining planks about the same size. I remeasured the remaining distance from that third plank land mark to the "new" shear mark and divided by four and marked them on the mold. I took my trusty battens and pinned them to the center mold marks and clamped them to the stem and transom. I fudged them around on all of the other molds until they looked eye sweet. Now that last sentence took me two or three hours to do. Things didn't look quite right at the transom so I added a bit of width to the garboard, broadstrake and third plank as I did earlier with the center mold to take up some of the flat bottom sides. That looked better. Of course that meant that I had to readjust the battens on all of the other molds again. When I was able to look at the battens from all directions, fore and aft, quarter views and the all important side view, which due to the height of my jig had to be done bent over upside down, I marked all of the molds.
I use this trial and error method, Ian Oughtred uses a mathematical formula and others use other methods and they all work to get you to a place close to where you want the planks. The final positioning of the planks has got to be done by eye. When your done with all of this, sleep on it. Check it again in the morning after your eyes have untwisted.
Again, this is only one way to skin the cat. It has worked out well on three lapstrake hulls which I've lined off.
03-26-2006, 08:21 PM
Thanks so much. I saw your 16' version at Lake Union a few years back and was quite impressed.
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