Paul,

To each his own.
I already agreed you can make things as light as you want, taking the risk you want.
I'm sure we are boring the rest of the forum.

Please demonstrate your OSB kayak.

Real world damage tells me that I want more than the minimum.

I also dislike the work and expense of glass and was interested in a practical alternative.

Marc

: How strong does it ned to be? the water pressure compressing the
: wood is under 1/2 p.s.i. A sheet of paper can hold withstand a
: dozen times that. Cardboard and thin wood are hundreds of times
: more resistant to pressure.

: True, but he is overlapping two strips. Each strip has it's own
: grain pattern, and the combination seems to let one layer of
: strips reinforce the adjoining layer is made from veneers. Some
: are cut like thin boards. Others are cut in a rotary manner, and
: the resulting grain pattern is nothing like what you might see
: in a cut board.

: Use enough glue and you can make a "board" from shredded
: wood fibers or even sawdust. Not sure what grain would have to
: do with something like that--but particle board and OSB, in the
: proper thicknesses, are structurally sound. Epoxy over a strip
: turns it into a combination of wood and plastic. The resin which
: soaks into the wood greatly strengthens it. To some extent
: varnish and polyurethane coatings also add a small amount of
: structural change to the wood.

: "added thickness in certain places" might be more
: accurate.

: With thin strips the direction of the grain has more to do with its
: ability to bend, or resist bending. A bow (archery) has the
: grain running from end to end and when you pull back the string
: it flexes, first absorbing great pressure in compression (on the
: inside of the bow) and tension on the outside of the bow, then
: releasing that when the bow string is released. In a boat the
: load is mostly carried by the gunwales, and the ribs transmit
: this load along the sides and up to the gunwales. They could do
: this with any orientation of the grain. One way might be
: slightly better than another, but the size of ribs can be very
: slight, and they will still do their job. Check out the minimal
: framing used by Platt Monfort's Geodesic aerolite boats
: (www.gaboats.com)

: The people at Pocock might be surprised to find that they are
: antiques: The company has been around over a century (1911).
: check out their site at www.pocock.com . The Wooden Boat
: Foundation in Port Townsend WA inherited the mold for forming
: the Pocock shell about 2005. I saw it in 2006 when they were
: setting it up. Since then they have produced a few new
: 'antiques' and sold them to subscribers as fundraisers. I just
: found a recent webpage about these boats at:
: http://www.pocockclassic.com/ or try
: http://pocockclassic.com/Pocockbrochure.pdf which shows the old
: mold.

: There is a central frame of sugar pine which serves as thwarts and
: replaces ribs. As i recall, the crossection on these pieces is
: only 1/4 " to 3/8". More like toothpicks than ribs!
: The deck is of a thin fabric. Fabric and hull are varnished. no
: epoxy. No fiberglass. Just strong wood.

: You would get a lot of strength by laying the two layers at 45
: degrees to the centerline. They would cross each other at 90
: degrees. Going from one gunwale to the other you could probably
: fit the strips fairly quickly. Bead and cove just might be
: practical here. Quickly applied square -edged strips which don't
: quite fit together might leave big gaps with a single layer of
: strips, but when you put on a second layer--even if the seams
: are not very tight, the only areas which might leak are the
: small points where neither layer covers. Those small points will
: be filled by your glue or epoxy, or sawdust and varnish as you
: fair and finish the hull.

: Starting at the keel and working to the gunwale, with each side of
: the boat stripped in a herringbone pattern gives a central seam
: which can be backed by an internal keel or keelson. The second
: layer again starts at the keel, but goes 45 degrees in the other
: direction. The boat has an intersting diagonal pattern. The deck
: can be stripped herrigbone to match, or by laying straight
: strips.

: The idea of crosswise weaving of fibers, split wood, or wide plant
: leaves goes back to antiquity. The earliest common reference to
: this is the biblical reference to Moses being placed in a
: cradle-sized boat. Same pattern, but we are not weaving the wood
: strips (they are too thick to bend easily).despite all the seams
: and joints, woven baskets can be made which will hold water--the
: fibers swell to seal the junctions.

: Hope this helps

: PGJ