: Guess my main concerns are overall weight and structural rigidity/flex of
: wood vs. aluminum. Wondering what kind of hit it can deflect before it
: permanently bends and if there are other factors/concerns I should be
: taking into account. I'd be grateful for any advice to be offered.

Todd,

Either wood or aluminum make an excellent stringer material for non-
traditional construction. Wood is normally less expensive than aluminum
unless you plan on clear cedar or clear redwood.

Wood's many benefits are well documented so I'll focus more on aluminum tubing
as there are some misconceptions about it's suitabilty for this application...
mostly by those who have never used it

Aluminum is very strong and has a nice consistent flex to it. All stringers
have the same flex characteristics. Of importance to me is that it requires
no shaping, sanding or finishing. Weight may be a bit heaver than wood
stringers, though it depends on the wood being used, and the grade and wall
thickness of the aluminum.

Another factor to consider is whether the aluminum frame is a folding kayak
style construction with it's "looser" snap together connections and "looser"
tubing section breaks which make for a very flexible frame, or....

A non folding aluminum SOF with lashed/epoxied construction with rigid
connections and no take-apart tube sections. You can make a more flexible non
folder by using folding type construction but I see no reason to do so as both
types perform well.

Bill mentioned George Dyson's use of lashing for aluminum frame flex, but Dyson
soaked his lashing with epoxy so it's about as rigid and strong a joint as
you will ever find. I consider this the best overall way to build these non
traditional SOF's.

Having said that, your boat will be in water, and not on pavement like the
bike framesets you mentioned, so they are an apples to oranges comparison.
The alum kayak frame will flex a bit, plus the skin will also... so no
worries about "jarring" Put another way, no SOF will ever be as rigid as a
hardshell, and most kayaks are hardshells.

Tensile strength of the 6061 or 6063 aluminum you will use is approx.
40,000psi so it's very strong. Metal fatigue is a total non issue for a
kayak. Damage from impact is likely no different than wood. I've never had
to replace an aluminum stringer due to impact damage going back over 15 years.

I like wood frame kayaks but find aluminum to be an equally good frame
material and for me a quicker build.

The attached BIF-16 Baidarka has 3/4" X .035 wall 6061-T6 stringers with 1/2"
exterior grade ply cross sections. The frame is lashed / epoxied. It's
light (26lbs), and very strong. The one-piece 8oz nylon skin is brush coated
with Dupont Hypalon.

I'm currently working on a new builders manual for aluminum / plywood / lashed
construction. Either of the Baidarka's currently in the wood frame manual
Nikumi / Nikumi 19) can be built this way, as can any boat in the manuals
except for the Sonnet's.

Have fun deciding.... It's a win-win.

Yostwerks BIF-16 Baidarka (lashed) - All 3/4" tubing / plywood sections
http://www.yostwerks.com/BIF16LashA.jpg

Dyson Baidarka (lashed) - 3/4" gunwales / keel and 1/2" chines
http://www.yostwerks.com/DysonAlumLashA.jpg

Tom