: I believe that almost any combination of materials you come up with will have sufficent ridgidity. My 3mm 4oz glass kayaks are ridgid, the closed construction insures that (like an intact eggshell). Impact is a big one to test. Many of the ideas below will do the job . Most of the kayak aplications would involve both sides being clamped with a impact load to the center of the beam or maybe an impact load to the center of a clamped drum. The other faiure mode to consider is fatigue. Delamination due to cycling loads on the hull or decks. is a realistic failure mode which is only approximated by static deflection or impact tests. You could rig this up with a small gear motor with a cam which defects the center of a supported beam or drum as above. You could also consider doing any testing on wet samples if you want to explore the real world.

OK, it's Science Fair Project time...........

: My son and I are interested in testing some of the common and maybe not so
: common materials used in kayak construction and comparing them. I would be
: interested in opinions on how to set up simple, repeatable tests that can
: be performed at home without expensive testing equipment.

: I would suggest two of the primary characteristics we are looking for in
: kayak construction material are rigidity and collision damage resistance,
: each in relation to weight. Rigidity is pretty simple. Collision damage is
: more complex, a function of a number of physicals (tensile strength,
: compresive, etc.) as well as structure design. I'd like to get past the
: physicals and onto tests that actually reflect the stresses put on our
: boats. I mean, when was the last time you pulled your boat apart end from
: end (i.e. in tension).

: I've seen a couple tests one can do at home: 1) Bend strips of materials over
: an edge with increasing amounts of weight on the unsupported end
: (cantilevered beam) until breakage. I think the Gougeon Brothers did
: something like this a while back. Seems like a good test of rigidity and
: how far a material will bend before it breaks and how it breaks.

: 2) Support a panel on its edges somehow and drop increasingly sized weights
: until failure to simulate running into a hard object like a rock.

: Any other ideas?