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Skin-on-Frame: Siskiwit Bay MC, progress report *PIC*
By:Wayne One (wwfloyd)
Date: 7/30/2011, 8:39 pm

It's about time for a progress report for Bryan, and any other interested parties. I did a plastic wrap test today, and will get her skinned in polyester, and painted, in the next several weeks.

No water got in the boat, in 25 minutes. I don't think I'll do plastic wrap tests, in the future. I picked up a lot of drag from the skin's wrinkles, and tape that didn't stick well, and plastic wrap that opened slightly to take water between layers, in places. I could only paddle slow, at which the boat has the very light feel that I like. Was nicely maneuverable, and plenty stable. Couldn't do any edging, without a coaming.

Since I weigh only 133 lbs., I scaled the Siskiwit Bay down to 97%, for 16 1/2 feet x 20 1/2 inches. I was interested in how well it sat in the water, and was fortunate to get a couple of similar shots to show the different waterline, empty and loaded. I also have a similar shot of my WS Tempest 165, and added it to another version of the shot, here: http://www.flickr.com/photos/wwfloyd/5990296471/in/photostream/
The Tempest is at a slightly different angle from the Siskiwit, so the (manipulated) scale between them is not quite accurate.

I had been worried about getting the primary chine swooped, and doing the long tapers at the stems. Turned out to be easy -- just did test fits, marked lines against the gunwale, and did the cuts on the band saw. At the bow, this required 2 angle cuts on each side. At the stern, only one cut per side was needed, as the chine attaches to the gunwale, but not directly to the stem.

It was nice to have Bryan's provided stem shapes to work with. I was able to design the final shapes from the templates, without having to wait until test fits could be done. The fit was perfect, except for my angle where the deck beam mates to the rear stem.

I had also been worried about getting the secondary chines to twist at the stems, with their serious vee shapes. That, indeed, was a problem. I made it worse by running the secondary chines more horizontal, rather than vertical; this was for the purpose of implementing the seat board (and foot board) system I've used before (1/4 in. ply, suspended by rails attached to keelson and chines), and to not have the chines taking up more height under my seat. Chines on the vertical would have made for less twist needed, but, I still don't think I could have made it. So... the notches I had put in frames 1 and 6 had to be modified to allow the lower chines to run out straight to the stems. A bit of an ugly hack, which left the effective chine slightly off from designed position. If I was doing this again, I would design horizontal-ish slots there, from the start, and perfectly positioned.

I was able to use a heat gun to put curve into the front deck beams. The 1 in. x 3/4 wood was difficult to manipulate this way. The deck shoulders leave some room for interpretation. What I got out of it seems acceptable, but, I think it could be done better. The back deck came out perfect, and the sections behind the cockpit are strong enough to do various self-rescues.

Beyond the technical concerns noted above, I had reservations about one of Bryan's design choices, even before I decided to do the build: the distance between frames 3 and 2, ahead of the cockpit, is a whopping 34 inches, on the full sized design. And, then 30 inches IIRC, between frames 2 and 1. Since there's a relatively short distance from frame 1, on, it seems the distances could have been better distributed.

I was worried both about strength, and deformability in the section ahead of the cockpit. My plastic wrap test did give some credence to that concern. OK, the plastic wrap was probably much tighter than the real skin will be; it had to be stretched tight to make it stick to itself. So, I did get some significant deformation of the chines, even in the shorter section (and even the gunwales, before I slit the skin for a cockpit opening). And, to be fair, the Radiata pine I used (for cost and availability) never did seem to have the same degree of rigidity as the cedar I've used previously.

I think that about covers it. I look forward to trying the boat out for reals. I'm grateful that Bryan put out this design, as I had long wondered why something like this did not exist. It has been a bit of a challenge, so, I'd recommend it for those that have previously done a Yostie, or two.

Messages In This Thread

Skin-on-Frame: Siskiwit Bay MC, progress report *PIC*
Wayne One (wwfloyd) -- 7/30/2011, 8:39 pm
Re: Skin-on-Frame: Siskiwit Bay MC, progress repor *PIC*
Wayne One (wwfloyd) -- 7/30/2011, 8:41 pm
Re: Skin-on-Frame: Siskiwit Bay MC, progress repor *PIC*
Wayne One (wwfloyd) -- 7/30/2011, 8:43 pm
Re: Skin-on-Frame: Siskiwit Bay MC, progress repor *PIC*
Wayne One (wwfloyd) -- 7/30/2011, 8:46 pm
Re: Skin-on-Frame: Siskiwit Bay MC, progress repor
Bryan Hansel -- 7/30/2011, 11:39 pm
Re: Skin-on-Frame: Siskiwit Bay MC, progress repor
Thomas Duncan -- 7/31/2011, 9:32 am
Re: Skin-on-Frame: Siskiwit Bay MC, progress repor *PIC*
Wayne One (wwfloyd) -- 7/31/2011, 7:25 pm
Re: Skin-on-Frame: Siskiwit Bay MC, progress repor
Bryan Hansel -- 8/1/2011, 10:36 am
Re: Skin-on-Frame: Siskiwit Bay MC, progress repor
Wayne One (wwfloyd) -- 8/1/2011, 10:40 pm
Re: Skin-on-Frame: Siskiwit Bay MC, progress repor
Bryan Hansel -- 8/2/2011, 12:35 am
Re: Skin-on-Frame: Siskiwit Bay MC, progress repor
Wayne One (wwfloyd) -- 8/2/2011, 7:46 pm