: Zimmerly/Morris use lashings & pegs while Putz uses screws and glue for
: fastening. Zimmerly's article indicates that the lashings allow more
: flexibility. Do they offer comparable strength? Possibly the willow and
: oak thing?

Putz's boats are skin on frame, but they are not "traditional" skin on frame boats. He applied modern design and joining techniques to traditional materials. His boats are meant to be rigid. On the other hand, Morris' and Zimmerly's methods are based on traditional Inuit/Aleut construction techniques and are designed to produce flexible boats. I can't honestly say that I can feel the flex in my Morris style boat, but it's definitely not as rigid as 'glass.

: Putz uses external keel and side rub strips. Looks like a nice idea, but
: something seems scary about screwing through your skin after you went to
: all the trouble to get it watertight. Does this make the boat leak, or
: does it seal pretty well with the screw pressure?

If you look at any traditionally built boats, they will usually have sections of bone pegged to the keel and chines to reduce wear. It worked for them and they didn't have screws or glue. I had to install a skeg on my boat and it worked fine when screwed through the skin. I used polyurethane glue in addition to screws to hold it in place. I also made it a point not to drill completely through the keel stringer. If you feel that you'll be replaceing your rub strips frequently, don't glue them. Another alternative is to coat them with epoxy and even with a layer or two of fiberglass, if you like. That way, you can just repair them as they wear.

: Putz skins the bottom and top separately, while the others are skinned with
: one big piece. Any particular reason?

The fewer the seams, the fewer places for leaks to occur.

: The Zimmerly boat from a recent Sea Kayaker is flat bottomed. How does this
: type of boat paddle compared to a v bottom hull? More initial stability,
: slower? I'm thinking of shrinking this boat down to 18 feet which gives it
: a 21 inch beam. Should still float, huh, or will I be paddling upside down
: the whole time?

Why not just build a boat using anthropometric measurements as outlined in Morris' book? The likelihood of your first boat being your last is pretty remote, and the best way to figure out what you need is to build one and analyze it's handling. Then you'll have a better idea of what to change in the next boat.

: Putz makes his cockpit part of the frame, while the Zimmerly boat cockpit is
: almost free-floating on the canvas with only a few frame attachment
: points. Is that still pretty secure?

It's very secure. It's attached by stretching the skin very tightly inside the coaming, then sewing it it place. Depending on how thick and tall you make the coaming rim, you may get some flex in it, but it's not a problem. Mine is only 3/8" thick and 1" tall and it works fine.

: The Putz and Morris designs I saw use stem pieces, whereas the Zimmerly boat
: brings the keel and stringers all the way to the stem. Any advantages one
: way or the other? I'm guessing the latter is a bit simpler. I first
: thought the stem pieces would be sturdier, but the attachment points with
: the keelson and stringers could be a weak point.

Actually, the Morris method is simpler, since you don't have to cut the keelson out of a wide board. It's also a more efficient use of materials, since it's just a straight piece of stock that doesn't flare out at the ends. Make sure that you have 8" or more of contact area between the stem/stern plates and the keel stringer so you have plenty of room for pegging and it will be very strong. Remember that the skin helps hold it all together, too.

: Does anyone make these boats with bulkheads and hatches? Seems like you'd
: have to tie ropes to everything you stuffed into the bow or stern to get
: it out again.

Hatches are certainly possible (Feathercraft has them on some of their boats), but I don't see how you could possibly get a bulkhead to seal on a flexible boat.

: Maybe I'm overthinking this. My guess is all of these boats work!

Bingo! One of the biggest obstacles I found to building a skin boat was being obsessive over small details. The best advice I can give you is to just buy some wood and build a boat. Let the process take you where it may. Make minor changes in design or construction that make sense to you. Trust your instincts.

: I'm probably going to adapt from both styles.

Rather than combining styles, I'd pick one and look at several sources of instructions. I used Morris' book, Cunningham's articles in Sea Kayaker and Boucher's video tape. H.C. Petersen's books are also excellent, if you can find them.

Combining Putz's method with traditional methods is not likely to yield good results, as they're aimed at making very different boats, despite appearing outwardly similar.