Lofting a 13'? Melonseed - Barto v Chapelle

[EyeInHand]

I noticed an odd discrepancy in the Barto plans, in that sometimes it is referred to as a 13'4" boat and sometimes as 13'6". I shrugged this off as a typo at first - no biggy. The Chapelle plans list the boat as exactly 13'6.5", though. I thought, hmm, which is it, and if they're different, where did the other 2.5" go?

I've been studying the offsets of both plans, and so far I can only find one place where they differ in length. The distance from Station 12 to the end of the Transom on the Chapelle plans is 13" - on the Barto plans it's 11.5". I guess that means the Chapelle transom has slightly more rake in it to be a tad longer. But that still leaves a missing inch somewhere. Anybody seen where it went?

There are some other slight differences in the offsets here and there, mostly by an eighth of an inch in one measure out of maybe 10. I've found what appear to be obvious errors in both (like where the measure says 6" wide when it must surely be 1'6"). But for the most part they are identical.

Anybody notice these differences? Any idea why Barto would have shortened his boat? (Maybe to reduce the angle of the transom to make all those compound curves easier to twist into ply?) Or is there another error somewhere, and if so, which is right?

Something tells me that once you start laying things out you could make it work either way. On the other hand, it could really s*ck to find out otherwise when the boat is 3/4 done.

Experts wanted.

Thanks,
Barry

(cross-posted in the Builders Forum)

[garland reese]

Well, I'm not anywhere close to an expert of anything......

I'd imagine you'd find most problems and even solve the fairing issues by doing the lofting. Could the length be attributable to the fore and aft width of the stem? I'm not familiar with the Barto plans, other than the pics on the WB catalog.

Beautiful little boat, the Melonseed.

I have a partial lofting of the Chappelle lines, in the loft of my buddy's hanger..... just waitin' for me to finish it up....

[John E Hardiman]

If you're lofting it doesn't matter. You're going to get your own lines anyway.

JBTDT.

[EyeInHand]

I entered both tables of offsets into Excel and had it look for differences. Almost identical, 1/8" here and there, except 1 1/2" difference and 1/2" at two points in the aft quarter.

I used the offsets to create the Station molds in Adobe Illustrator - sort of doing digital lofting. Just entering the numbers brought out several errors in both sets, though more in Chapelle with several transposed numbers.

Stacking the molds I could see where neither would be fair, though a little tweaking brought them in. Barto's templates for the molds in a few cases look significantly different from what the offsets produce. Looks like he chubbed up his templates, making them more full. If you use his templates looks like you'll be fine, but if you do your own lofting expect to "refine" a bit.

Checked the Stem dimensions and they're the same, so there's still the mystery of different length boats.

For the record, for people working from the Chapelle plans, here are the errors I found:

Transom - Half Breadth - Waterline 9"
says 1.6.1 /should be 0.6.1

Station 12 - Half Breadth - Waterline 9"
says 1.8.4 / should be 0.8.4

Station 11 - Half Breadth - Waterline 12"
says 0.9.0 / should be 1.9.0

Station 6 - Half Breadth - Inner Rabbet
says 0.0.6 / should be 0.6.0

[Steve Lansdowne]

Hey, this post is also in building/repair. Let's do all our posting at that location to keep it in one spot.