> Jeff

> You can find the challenge at George Roberts' site. (see link)

> My original post in this thread was about a process I felt would save
> weight and increase strength when building a strip kayak. I feel that 1/8
> inch cedar strips would save a lot of weight, and not weaken the boat.

> I am interested in the boat you built with 3/16 strips. As there is really
> no way of telling short of destructive testing, in your opinion, was the
> boat as strong as a similar boat made with 1/4 strips. Was the hull or
> deck more flexible, did it flex noticeably if you lifted it while loaded?

> Also what kind of layup did you do on this boat? (single/double-6oz./4oz)

> Thanks for any info. Ian Johnston Ian, A little history might be helpful: I've built a wood-canvas baidarka, two cedar strip (using 3/16" each), a Chesepeake 18 from a kit (using 4 mm Okuemme) a Glen L rowing and West River 162 using 1/8" Luan. I've mainly been playing with strength to weight of plywood versus strip. I haven't noticed any reduction in strength from using 3/16" cedar vs. 1/4" Remember, that unless you're very good at getting the hull fair as you glue, the sanding and planing will decrease the thickness considerably. I'm sure that there are places on the hull that are more like 1/8" I used 6oz. E cloth inside and out but put an extra layer on the bottom of the hull (needless over kill). One other building change I used was to not tape the hull/deck seam but use a sheer clamp stitch and glue style. This may make up for some strength differences.

I will say that using 1/8" Luan as buiding material make for a very flexible hull (not great in rougher water for me). I paddled it off Spruce Head in Penobscot Bay, Maine a weeks ago and really felt odd waves transmit through the hull. Unfortunately I don't have an equal comparison for the the strip kayak due to its extreme design (Ultra low volume). I took it in the ocean once and was too concerned about staying upright to notice any flex. I do know there is almost no flex when I enter and exit the boat (I weigh 235 lbs). This hull is far stronger than a standard glass lay-up on a 43 lb. Wilderness Systems Arctic Hawk I've paddled!

I'm no more than a composites novice, but I think the only reasonable way for me to reduce weight for a touring boat would be to switch to S-glass and be more careful with my epoxy (not glop too much on).

I have plans for CLC's Patuxent 19.5 and I'm currently thinking about how to use the plans to make a strip version. They use 4oz. cloth and 3mm plywood to get a racing hull (and don't glass the plywood deck) to arrive at 34 lb. boat. I think I should be able to match that weight or reduce it using the equivalent of 3 mm strips. I just measured and realized 3 mm = 1/8" whereas 4 mm = 3/16" Since I already have a rock solide touring boat I would be very willing to try 1/8" strips although I might play it a little safe and mill them 5/32" so with minimal sanding they would come out 1/8 thin. To keep cost down I would probably still use the 5.5 oz. E-glass I have been getting at Hamilton Marine in SearsPort Maine. I also have switched from West system epoxy to MAS. I have found it much easier to work with and I get a very clear coast without having to switch to another hardener.

I hope I didn't blather on too much. Good luck Ian.