54 replies to this topic

[takesiteasy]

My brother and his family go to Waldo Lake- one of their favorite spots.

[Wandering Sagebrush]

My brother and his family go to Waldo Lake- one of their favorite spots.

It’s a great place to donate blood. The mosquito population can be astronomical, but it is so beautiful... just be prepared.

[Squatch]

I've been doing some reading and I'm really warming up to the idea of one of these skin on frame boats. i think I'll be picking up a couple of books soon.

 

I like the idea of a canoe that's light enough to put on the camper roof and not have to take it off to raise the roof.

 

Takesiteasy, Have you ever built one in the fuselage style like Kudzu boats uses? Some aspects of that seem like it might make it easier to copy some patterns like the kite I posted.

[takesiteasy]

I have built several fuselage style kayaks and stand-up paddleboards but not a canoe. The frame style makes more sense to me for a fully enclosed boat than for an open canoe. It is definitely easier to build the fuselage style. The strongback is simpler for the fuselage style boats since the frames are basically the forms. The downside is the frames extend into the boat and kind of get in the way on the floor (my opinion). The wider spacing of frames also means larger dimensions on the stringers which can make the boats somewhat heavier. The boats can be very attractive.

 

You can copy a more complex boat shape with the bent rib style skin-on-frame construction- you just have to build the strong back forms to match. One of the fellows at the shop builds SOF canoes without a strongback which saves the work of making the strongback but I would not recommend it for the first boat you build.

 

Edited by takesiteasy, 11 February 2018 - 05:22 AM.

[Squatch]

You just verified exactly what I was thinking.

 

Another question or few if you don't mind. I see 3 different fabrics commonly used for covering. Nylon, Dacron, polyester. Can you give pros and cons for each?

 

How about substances for covering the fabric? I've also seen quite a variety from plain paint, spar varnish to exotic 2 part resins. Even Mylar film. 

 

I've read that products that soak into the fabric decrease tear resistance vs top coat type films. Care to take this one on?

 

2 layers of fabric for extra strength?

[takesiteasy]

Squatch, I have worked with both nylon and Dacron, which is a branded polyester. They are very similar in comparable weights and weave. We use a 9 oz. ballistic nylon. I like nylon better for several reasons. It stretches (especially when wet) which makes it easier to stretch around the boat shape without wrinkles. It shrinks as it dries making a nice tight skin. It is a tighter weave (we use ballistic) than the Dacron we have tried and is less prone to pull holes when sewing and tougher in use. Dacron does not stretch but shrinks with heat which can be an advantage in eliminating wrinkles during the skinning process, but in practice, the lack of stretch is a bigger disadvantage in my experience. I've read that Dacron accepts paint better than nylon but we have not tested that.

 

For waterproofing and wear coating, we use a 2-part polyurethane which is very tough and remains flexible after it cures. We work it into the weave as well as spread it on top of the fabric (3 coats done successively before cure). We have tried varnish and both oil-based and latex paints with less satisfactory results. The paint does waterproof the fabric but doesn't wear nearly as well as the polyurethane. Paint has the advantage of providing a wide range of color possibilities. It is possible to paint on top of the polyurethane with some surface preparation but we don't typically do that.

 

Here is a source for the coating (and other supplies): http://shop.skinboats.com/2-part-Urethane-System_c5.htm

 

We have tested tear propagation with the polyurethane coating and it significantly improves tear resistance of the nylon fabric, which is already very good before coating. You can cut the skin with a sharp knife but it is very difficult to continue to tear it by hand. I don't know as much about that issue with Dacron.

 

I've never seen two layers of fabric used and I don't think it is necessary. The skins are really tough.

 

I hope this is helpful. I really enjoy building the boats and talking about them. I do think they are pretty perfect for carrying around on the camper and puddle-jumping.

[Squatch]

Thanks again. And thanks for that link. I hadn't run across that. Lot's of questions covered in that link. 

 

I'm familiar with and have a lot of respect for Polyurethane products. I live in a log house that's caulked with Sika-Flex. I use it for a lot of stuff very superior product. I've also used several DIY bedliner type products that are 2 part PU. Both solvent and water based with good results.

[takesiteasy]

You're welcome. If you didn't find your way to the parent site, here is a link to that: https://www.skinboats.org/ Lots of info there too.

[TGK]

Regarding preferred fabric for a skin boat, years ago I had a single wall gore-tex mountaineering tent where they laminated the gore-tex to dacron vs the more commonly used nylon. I was told the rationale was that dacron is not as susceptible to UV degradation at high elevations as nylon. At the time, they also said dacron was used in sails for boats. Anyway, I don't know this to be fact but, if true, that would be one advantage of dacron. Of course, if the skin is coated or painted, that might provide all the UV protection needed.

[takesiteasy]

Regarding preferred fabric for a skin boat, years ago I had a single wall gore-tex mountaineering tent where they laminated the gore-tex to dacron vs the more commonly used nylon. I was told the rationale was that dacron is not as susceptible to UV degradation at high elevations as nylon. At the time, they also said dacron was used in sails for boats. Anyway, I don't know this to be fact but, if true, that would be one advantage of dacron. Of course, if the skin is coated or painted, that might provide all the UV protection needed.

 

Yes, Dacron is more resistant to UV than nylon and would be better in that regard. As you suggest, in the case of skin boats, the coating on the skin provides UV protection. We have not seen any issues with UV deterioration in the nylon skins but I suppose it could theoretically be an issue over time, especially if the boat is stored outside.

 

My understanding is that the lack of stretch as well as UV resistance makes Dacron particularly desirable for sails.