Skin on Frame Boats (discussion)

[Paul Pless]

I was looking at this boat which is just way cool. And, then of course there's the larger boats like Beckman's pictured below.

I guess my main question is: just how durable are they? Do the larger ones have an outer keel or shoe of some type to protect them from abrasion and impact, either of hitting the bottom or something floating in the water? How would the baidarka hold up to being swept over a gravel sandbar for instance? Is the skin repairable with a patch if need be? What are the practical size limits of these types of boats?

Just curious...


http://i174.photobucket.com/albums/w117/alias1719/DaveKidF.jpg

http://lh3.ggpht.com/_4gPfG4jYHQk/Sf7Gv8UxYUI/AAAAAAAAJ-Q/mPXvJziJWZ8/s800/P5011197.JPG

[Dave Wright]

Those are wonderful boats. Check out the Cape Falcon Kayaks site for some refelections on your questions:

http://www.capefalconkayak.com/

He launches all sorts of skin on frame rigs from sandy, high surf beaches.

You might remember his Sea of Cortez trip detailed in a past Woodenboat:

http://www.capefalconkayak.com/campcruisingcortez.html

I need to finiish up my latest ply effort so that I can start on skin on frame.

[Yeadon]

The material they're made out of is pretty tough, and you can always fasten sacrificial rub strips along the bottom.

[clancy]

I have a 17' Folbot Greenland II (http://www.folbot.com/kayaks/greenland_ii/)that I bought new in 1990. The boat has been through hell. The frames fall apart before the hull does. I've probably replaced all of the rivets in the frames over the years.

[Canoez]

They look to be pretty tough from what I've seen on other's boats.

I'm about to find out for myself as I've just finished a Greenland style stick (http://www.woodenboat.com/forum/showthread.php?t=97463&highlight=paddle)and am about to launch myself into a pair of Thomas Yost's Sea Tour 15R's. If I get my butt in gear, you might see it on the car at Lefty's, but we'll see.

I figure it this way - people have paddled animal skin/birchbark/cotton-canvas covered boats for a long time without huge complaints, so I don't know why people make a big deal out of skin-on-frame durability.

[PaulT]

Paul:

My experience so far is that hitting something floating in the water is likely not a problem. (I have indeed struck a couple floating boards, logs) Closing speed in the water is not that great and you are unlikely to hit something at other than a glancing blow. A 90 degree encounter is very unlikely and even then unless you row or paddle a lot faster than I do I doubt you would see any damage. Probably the most likely puncture would be upon beaching, hitting a submerged and very sharp object firmly planted in the sand/rocks. I have scraped the surface of the cover on mine in an ill advised approach to a cement launch area. The scrape however never leaked. The small, 1/2 inch wide cutwater / outer keel gets scraped from time to time. Takes an hour or so to sand it and re-varnish it for the next hit :cool:.
I am new to these craft, but so far, so good. As has been said here before. They are tougher than you might think. As far as patching goes, Duck tape will get you home, and then cover the hole or cut with a piece of the original covering and stick it with heat-n-bond, or varnish it in place or paint it in place... What ever. Not a big deal.

Sincerely:
Paul T

[James McMullen]

Number of Skin boats built:
2 canoes
2 Greenland kayaks
3 Aleut baidarkas
1 umiak

Number of holes:
zero

With modern fabrics and coatings these things are about as tough as a whitewater raft's hull. A cedar lapstrake hull is more fragile by far.

[Paul Scheuer]

I have a Folbot rigid 15' "Sporty" SOF kit that gets more use than any of my other boats. Although I originally worried about its durability, I've desided that it can take more than I can. Lately I've given up my patch kit, which is a tube of "sneaker glue" and some scraps of the hull material.

The hull is two layers or "naugahide" vinyl coated fabric, similar to car seat material. I've yet to break the gloss. I normally stay away from the concrete ramps but where I launch the "beach"is crushed limestone.

So I guess the answer to your question is it depends on the skin, and there are lots of choices.

[Canoez]

Paul : try this YouTube (http://www.youtube.com/watch?v=gYyvIExWkqU) posting on for size.

[Tom M.]

Paul, I just finished a Platt Monfort 11'6" canoe. I've had it out twice so far. I had many of the same questions as you. I have about $250 into it and maybe 50 hours. With such a small investment, I figured I couldn't lose. I got to build a little Wee Lassie, learn how to build a new way, got a neat little boat, and got many of my durability questions answered.

Bring along a roll of duct tape for the unlikely event that you'll need a field repair. I feel safe in her.

[AJZimm]

Paul,

I built a folding 18' baidarka to George Dyson's design 9 years ago, using 15 oz nylon coated with hypalon rubber household deck paint - 7 coats on the bottom and 5 on the deck (looks a lot like the boat in your picture, minus the graphics). The center of the keel is reinforced with another nylon strip that is glued on and also coated.

I've used the boat on a number of 1 or 2 week long trips on various places on Vancouver Island, usually on sandy beaches, and one month-long trip to the Queen Charlottes. So far the center keel rubstrip is a little scuffed at the stern but that's all. I've run into things but the combination of flex in the frame and the rubbery coating means it goes "thunk" and bounces off. I've also inadvertently passed over unseen barnacle covered rocks. The fabric seems to give and move away rather than puncture. No holes so far.

[Cuyahoga Chuck]

Skin on frame boats have a thousand years of testing on them so they must be fairly well thought out. They can be quite durable.
SOF kayaks don't weigh very much so they don't usually hit anything with much force. Smart SOF paddlers stick to blue water venues and dismount while still afloat to keep from abraiding the skin. Because they flex they are able to withstand considerable working forces. One of the choices for the skin is ballistic nylon. It's tough stuff but tends to get baggy when wetted. The other option is a similar weight polyester.
Also, those familiar with their construction claim they can build one for $150 or less.
Some builders even throw away their tape measure and use the Inuit method of anthropomorphic (using body parts for sizing) measure which tends to scale the kayak to the size of the intended paddler.
Frames can be made from scrap lumber scarfed to length. They can be lashed with fishing line.
The skin material has to be purchased retail as does the dental floss which is popular for sewing it up. The skin can be painted with common paints or varnishs. Popular choices for a cheap build are porch paint and the returned stuff bigbox stores sell at deep discount.
When you get into the big hulls like the item in your picture there are many more engineering considerations so the "make it up as you go along" technique is not advisable.
If ya' want more get "Building Skin-On-Frame Boats" by Morse.

[Canoez]

If ya' want more get "Building Skin-On-Frame Boats" by Morse.

(Robert) Morris, ya mean? :confused: Or am I missing a good book for my library?:D

There are also good books by Mark Starr and Chris Cunningham, as well.

[Paul Pless]

Excellent feedback guys.... the various types are certainly intrigueing.

I look forward to seeing your boat if possible at lefty's, Canoez.

[Canoez]

The way things are going, I might be lucky to have frame-on-frame!

:D

[Wooden Boat Fittings]

.
And to add to all the above, I have a canvas kayak that will be 50 years old next year, still in (occasional) use and still not holed.

To take bottom wear she has a 1" x 1" full-length softwood keel, and short curved bilge keels (3/4"v x 1/2"h) midway, just below the turn of the bilge; also brass half-round on stem and sternposts running down on to each end of the keel.

Mike

[Cuyahoga Chuck]

(Robert) Morris, ya mean? :confused: Or am I missing a good book for my library?:D

There are also good books by Mark Starr and Chris Cunningham, as well.

Whatever his name is he actually built a Providence River Boat, which is a dinghy style hull with a transon. That's the reason I mentioned that particular book. The hull produced was NOT entirely of lashed construction. A lot of the build involved techniques common in traditional boat building like copper nails, roves and breasthhooks to stiffen the the transom. That's a lot different than what's done on a Baidarka or a a West Greenland.
If Starr and Cunnigham cover that stuff God bless them but I am not aware that is the case. If I am wrong can you update me with chapter numbers?

[Canoez]

If I am wrong can you update me with chapter numbers?


No, they discuss Umiaks a bit, but don't show illustrations of other skin-on frame boats in either book. Morris has that section at the end of the book with a very wide variety of SOF boats.



Is this one of your shapes?
http://gallery.bateau2.com/displayimage.php?album=343&pos=17
If so, thanks.

???

[DGentry]

"I was looking at this boat which is just way cool"

Thanks!

Skin boats can be both framed and skinned from a variety of materials - and a variety of material weights. You can just choose your scantlings and skin toughness as needed. For instance, a "Kidarka" doesn't need to be as tough as a multi-person iceberg dodging umiak!

Protective keel strips are fairly common - whether they are of wood or just an extra layer of material. But they aren't required for many kayaks.

This kid's boat, or any skin boat I've made, would have no problem being scraped over a gravel sandbar - assuming no knife edges. Even should you get a puncture, it would likely let in very little water, and wouldn't just keep expanding. Yes, as others have said, it's easy to patch if necessary.

As for practical size limits, well, there are big umiaks, and Irish Curraghs came in very large (for small boats) sizes, too. Then there's George Dyson's enormous Baidarka, documented in his book. It's 48' long! I guess, in theory, one could build a world cruising capable skinboat - though I'd be leery of hitting a mostly submerged container. Of course, that'd be a problem in most any boat . . . .

Skip Snaith wrote the book on Umiaks. Interlibrary loan is your friend!

Dave Gentry

[David Geiss]

I had the pleasure of meeting Skip Snaith a while back and find his book re Umiaks very inspiring. He is very much of the school that says "build it" and don't get bogged down in technical detail. He is very much an artist and I would highly recommend reading this book.
David

[dm_scott]

Looking for a "big" one?

http://www.arctickayaks.com/Lines/LinesKodiak3-holeMAE536-24.pdf

You can access some other great .pdf file plans from David Zimmerly here, lots of choices and no need to pay for the plans. His site is full of great info on traditional and historical kayaks.

http://www.arctickayaks.com/plans.htm