: I made a large panel from strips to make bulkheads for my strip
: project. I noticed how strong the flimsy panel became after I
: glassed both sides. This was a very good demonstration of how
: the fiberglass sepatated by the 3/16 wood resisted bending after
: being bonded into a unit. Nick Schade has a nice write-up on
: this in his books where he compares the new structure to an
: "I Beam".

: The fact is that the fiberglass alone is very flexible and has
: little strength on its own. Unless you significantly thicken the
: glass layer with woven roving (like my 18' runabout) or a middle
: layer of foam or better yet, cedar, you won't have any strength.
: Adding roving (and resin) to the glass cloth weighs a lot.

: The lightest kayak you are ever going to be able to build is a SOF
: using lightweight cedar or other light woods for the frame and
: lightweight cloth (nylon,etc) waterproofed with a paint product.
: To avoid the frame that interferes with your interior volume,
: the next best solution (weight wise) is a fiberglass cloth
: covered cedar strip boat. SOF and Strip boats of the same design
: can be very light with the strip boat weighing only 8-12 lbs
: more if you build very carefully.

: I love hearing and thinking through new ideas about building but
: think a fiberglass cloth shell made over the frame of a SOF
: design fails to meet the strength test without reinforcement
: that reinforcement would make it fail the weigh test.

: SOF and Strip are well proven light weight construction methods....
: I'm building a 17' Spring Run that is ready for varnish and is
: weighing in at 33lbs. That's with 2 layers of 6oz cloth on most
: of the bottom and a double layer around the cockpit and hatch
: openings. Should weigh less than 40 fully rigged.... Compare
: that to my 14' Dagger Alcemy rec/touring boat that weighs 53lbs.

: Bob Beaullieu

Hi Bog,

Nick's thing about comparing a sandwich construction method to an I beam isn't original, been a standard comparison in many texts for years.

BillH.