: Yes, frequently, but it can be close. And, of course, you can overbuild (or
: underbuild) either way and introduce bias. The old wood canoes used to
: weigh in at about 65 to 75 pounds dry. They had a heavy canvas and oil
: paint covering, and thicker wood sides, as well as thicker and wider ribs.
: And they were seldom dry. I'd guess they soaked in another 5 pounds in
: water after a few weeks of use.

: Not necessarily. Which is going to be stronger, a blanket or an I beam? The
: physical size and shape of the rib acts like an I-beam in how it stiffens
: and strengthens. The thicker the rib, the more the effect. A layer of
: glass cloth is far more flexible. The surface bonding effect you obtain
: will keep the strips from falling apart, but it does little to stiffen or
: strengthen the hull itself.

: Exceptions do occur. Polyester resin would be stiffer than epoxy. Laying the
: glass in the shape of a rib would also make it stronger. Consider using a
: 1/2 inch diameter piece of foam as a rib mold, spot gluing that to the
: inside of the boat, and then laying glass over it. You'd end up with a
: very stiff tunnel of fiberglass about 1/2 inch high serving as a rib. This
: would be much stronger than a flat layer of glass cloth, at least in
: certain directions. I've seen designs which in fact specify ribs be made
: in such a manner, with a foam, or paper core.

: As for speed of application, or time involved. Not much time is needed with
: the ribs. Steaming them all at once you would take out onestrip of wood at
: a time and bend it around a mold. Working with 3 or 4 such molds at a
: time, you'd be pulling a cool rib out about as fast as you could get the
: wood out of the steam box.

: Now, making all the molds for those ribs would take some time. With a
: symmetrical hull--or one that was fairly close to being symmetrical, you
: might use the same mold for 2 to 6 ribs. with 4 ribs to a foot, on a 16
: foot boat, figure on 30 to 35 molds.

: Bending each individual rib is fast if you have the space to work in, so
: figure an hour for bending all the ribs, and setting them in their slots
: on the mold. After that, you just nail on the strips.

: With glass you need to add in a skim or seal coat, wetout coat and one fill
: coat. Inside a boat you don't need to completely fill the weave, but you
: do need two coats to be sure that cloth is well covered. You might skip
: the seal coat but that uses more resin. That's about 3 to 4 hours, plus
: any sanding time to remove lumpy drips or blobs, plus time spent waiting
: for the resin to get hard enough to sand. With the wait time, this could
: go three days or, typically, a home builder would do it over a couple of
: weekends.

: Fasteners? What are you using? Would dowels work? Drill out the wood, replace
: the sawdust with a round piece of wood of nearly the same weight.

: Seriously, tho, I do understand that issue. When you try to use a bolt or
: woodscrew with a thin wood hull, whether it is strips or plywood, the
: surface of the wood is not going to take a lot of force over the small
: area most fasteners cover. So you need to beef up the area around your
: fastener with more wood, additional layers of glass, or use wide and
: heavier fasteners which spread the loads over a bigger area. For example,
: embedding a "T" nut for mounting rails for adjustable foot rests
: adds much more weight than the "T" nut itself.

: Boats with ribs on the inside were a good idea for many years, but you can't
: just pop them out of molds, so you won't see them made in factories. And
: building one at home means lots more setup time and more jigs. For a
: single boat it is not practical. It is barely practical unless you want to
: start a small factory. Just guessing here I'd say you probably wouldn't
: break even with time and money versus glass on wood unless you made
: probably 6 to 10 boats off of a mold. After that I think you'd save some
: shop time and about $25 on the glass and resin. I may have better numbers
: on this in a year or so. I am strongly considering building a mold for a
: 17 to 18 foot touring canoe and using it in classes. Hopefully I'll be
: able to offer a class where someone can build their own canoe over such a
: form in 4 to 5 days. That would be three to 4 days working at assembly on
: the mold, varnish in the evening, come back the next morning to put on
: gunwales, decks, and hang seats and thwarts before another coat of
: varnish. The next morning varnish the inside, and take the boat home in
: the afternoon. A classic wood canoe with no glass. Or, spend a couple more
: days and glass the outside. You'd have a boat in a week. Rgiht now that's
: the goal, but the plans are still being worked on. Talk to me in 6 months
: or a year.

: PGJ

Current project is a modified Tom Yost skin on frame. First try for a new combination of two conventional materials, at least for me. This one will be "heavy" but am working on a sub 20 lb. sea kayak that's still useable. This one will weigh around 26 or 27 lbs.

Bill H.