: OK. Well, having preused these boards for about a year now, but not having
: built a boat, it would seem that the following would help you to build a
: light boat: First, start with a round bottom ("tortured
: plywood") design (such as Yare by CLC). Use 3mm okume; use fillets
: that are as small as possible; tape seams instead of glassing entire
: surfaces (such as the bottom or the deck); and use float bags instead of
: bulkheads. Using thin epoxy in minimum coats would also help. End
: "plugs" made of Balsa instead of end pours might also save some
: ounces. Use thin sheer clamps or rout/chisel/drill/plane out the sheer
: clamps as much as you can (don't be too aggressive here - careful!). Hey,
: gang - did I miss anything?

: Of course, many of these measures will affect the boat's durability and
: longevity and certainly the decision to go with a tortured plywood design
: has significant performance implications.

: I've noticed that the Yare is supposed to weigh only 26# or so. It's hard to
: get much lighter than that for a 16' kayak (shop around and compare).

: Finally, it appears that the point of diminishing returns is found rather
: quickly for most amateur builders, and that if it's the weight on the
: water you're concerned about, you'll probably find that it's easier to
: reduce the weight of the paddler than it is to reduce the boat's weight
: any further.

: I have been interested in building a very lightweight boat not because I'm
: worried about weight in the water, but because I want to portage my boat
: on my shoulder for a block and a half to the river each morning and I
: don't want to carry any more weight than I have to.

: I've pretty much made up my mind to build a (slightly modified) Yare for some
: of these reasons and for some I haven't stated.

I don't know too much about the Yare design, though It seems to have a reputation for being a bit "tippy". At 16 feet, even a lightweight boat can be a real challenge to portage if the wind is blowing. A short boat of the same weight is much easier to handle on the land, though no doubt in-the-water performance (i.e. speed) will suffer.
Stillwater boats offers a small tourtured ply design that is short and beamy.....like Nick's Little Auk or a decked over Rushton Wee Lassie. These make great little boats for portage and for paddling on protected waters. I'm not too sure of the plywood specs for the Sunrise Single, but the stated weight is #28.....maybe a bit lighter on the ply and you'd have something very light and easy to portage.?
There is also cold molded construction. Some racing shells are built that way, though you may not save that much weight over lightweight plywood construction, and there is most assuredly more work involved.
garland