SOF Plastic Wrap Test

The boat meets or exceeds my expectations - which were pretty high. Pretty crazy to go for something so specific and to take a chance on my own design ideas on a first build, but I think I got lucky. It seems my over-thinking this one to death paid off. I’m not going to change a thing!



Pictures are better than words, so thanks to Paul (who shot MANY pro quality shots) here are a bunch:



http://community.webshots.com/album/531428057EpNuZP



Paul also tried the Mark 1 surf ski. Earned his water wings and did quite well. He wants another go at it which says a lot. Next time I’ll get the wing in his hands.



Also along was Charlie -acting as my escort/wingman in his pretty white rolling machine - and giving me knowing looks as I kept finding more and more to like…

hardly pro quality
but it was great fun seeing the look of satisfaction on Kris’s face and watching the boat skim across the water. Of course it will be a completely different boat when it is skinned, but it is obvious that this boat is going to be a winner.



too many ribs though…



:slight_smile:



Paul

I hurt
there are sore spots and bruises that I didn’t know I had showing up on my torso thanks to trying to get on that damned ski so many times.

next time I am going to put som sponsons on that thing!



paul

Looks great!
Can’t wait to see how you finish it off. The unfortunate part is now you are hooked. Just like Lays chips you can’t eat just one.

Nice work,

Randy

Yup

OT The first time I said I’ll roll or do
a paddlefloat re-entry I did a dozen reentries; my legs had so many bruises my wife asked me if I paid the “entertainer” extra for them.

so what is next?
coaming and sewing? Let me know if you need another set of hands to stretch the nylon.



Paul

Are you up to speed in any of those
shots ?

no
Kris did not as far as I could tell bring that boat up to speed.



Paul

some speed Pat - can’t say which shots
Though it doesn’t show, I did get up a little speed. At least 5 mph a couple times by paddle feel, maybe more. Even with the irregular plastic surface it a smooth ride - so hard to say.



I was looking to try to see the same thing in the pictures - but there is so little wave train change over the ranges I was going that I can’t easily tell images which are moving more than others. I tweaked the entry/exit and chine stringers to optimize - and it seemed pretty sweet - but skinning and time will tell. I’m more curious how it handles wind and wave.



There are a couple pictures where I’m throwing water off the GP. Usually have to be kicking it a bit to see that (or I’m accelerating or just sloppy!).



http://community.webshots.com/photo/531430252/531430252BBChfs



Paul shot in burst mode so I have a bunch of 5 shot/1 sec sequences. If you’re really curious I can see if any show decent motion and send/post them.



From in the boat I was trying to see if I had any bow gurgles or noticeable bow wave issues. All I could noticed was due to the irregularity and softness of the shrink wrap. Made a peculiar percolating sound.



I almost taped the GPS on - but it will be faster skinned and will check it more then. Speed is one of the big remaining what-if at this point. As good as it feels, I wont be to concerned if it’s not as fast as I’d like - but at about 18’ x 18" - 12/1 ratio at the waterline, how slow can it be?

At least you get to exp. to see how
a mushier skin dampens things. Yep, did not think you were powering along in any of those shots. Can not remember if you mentioned it anywhere … did you weigh the frame ?



Just wondering.

it’s a stone!
L



I think it weighed in at 41 lbs. I think the floorboards added a lot to the overall weight.



Paul


38 lbs +/-
The floorboards did add about 2 1/2 lbs.



Ranges I’ve seen for these are anywhere from 20 to 40. Frames seem to average upper 20s to low 30s - for 17-18’ qajaq. If you take off the floorboard weight, mine’s about 35+. Not too bad for a nearly 20’ boat - plus it is built tough as I didn’t intend a pond roller.



Finished weight will be low to mid 40s. I could build another and shave that down to as light as a glass ski that would still be pretty strong by going to 1" wide ribs, laminated masik, more minimal deck stringers, and a lighter foot rest beam. Gunwales, stringers, stems, and flat deck beams are already as light as I’d go.



Regarding skin - I don’t think it will be as “mushy” as you may be thinking. Seem many SOF around SD? I know there are some. It will give some - but even the stretchy plastic wrap held it’s lines pretty well. I’ll be using junior ballistic nylon pulled tight and shrunk a bit, stabilized by urethane, and the widest gap it has to span between stringers is only about 6".



Certainly some speed penalty over a hardshell - from skin flex and hard chines (minimal and offset but narrower beam vs most commercial hulls), but the feel is more than worth the trade-off. I could tell that just from the brief testing.

stretch / sag
I checked Charlies boat before and after the paddle and did not see any appreciable difference in the nicely tight skin he had on his boat.



Paul

Before/after is not the issue
It’s the deforamtion while in the water, and loaded, with water pushing in on the skin that matters.



The shape in the water is not the same shape you see on shore. The flat skin panels curve in, creating scalloped/concave vs. straight cross section lines. See Morris for an illustration (page 101) if you have it.



You may have noticed I was reaching under the hull and feeling around, and also looking inside as best I could to see how shape was reacting. Not that the plastic would tell me much, but was curious anyway.

books
Unfortunately I left all three of my books in North Carolina last time I was there.



paul