: 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

Hi Tom,

Like I'd said, just got Dyson's book, leafed thru it but not read it yet

Bill H.