:
: : The trade off for making the wood thinner is you make the boat weaker.

: : The stiffness of the skin varies by a cube (thickness^3) This means that the 1/4" strips will be more than twice as stiff as the 3/16".

: : I prefer to save weight by using thinner glass. You don't save as much weight, but you retain more strength.

: It has been years since I debated mechanics with anyone but I will try.

: The "cube" rule based on the skin thickness is not relavent for two reasons:

: 1) Even though fiberglass whitewater boats (6 layers of glass) are not as stiff as 3/16" wood core with 1 layer of glass on each side, but the whitewater boats are stiff enough for efficient openwater kayaking.
: You can make boats stiff beyond need.

: 2) You are using the wrong "thickness". A kayak is a tube. For a tube the stifness is directly proportional to the material thickness.
: So a 1/4" boat is only 33% stiffer than a 3/16" boat.

: 3) There are very few people who are strong enough to bend a kayak enough to affect its performance.

: But in any case, the intent was that if a boat is going to be made thinner. It is easier to start with thinner material and remove less than it is to start with thick material and try to maintain a uniform wall thickness.

The advantage of stiffness is it distributes force. Stiffness does not equal strength but it does contribute. I am not addressing the stiffness of the overall boat, but the stiffness of the skin when you hit a rock.

For this purpose the thickness of the skin is what you are interested in. You are not looking at the kayak as a tube, but a section of the skin as a panel. A fiberglass WW kayak will flex locally as it hits a rock. It is strong enough locally that this bending does not break the boat. A stripper bent the same amount would break. However, because it is stiffer it distributes the force over a greater area so the locallized force is less and it does not break.

This is not to say tha the stripper will not be damaged, there may be abrasion damage to the thin coating of glass and if this damage is severe enough the whole system can fail, but barring adding 6 layers of cloth for abrasion resistance you will get a relatively stronger boat by using thicker strips.

If you are going for the lightest boat possible, by all means use thinner strips, but it is worth considering the trade offs. A stiffer skin is not neccessarily better it is just one alternative that has it's own set of advantages and trade offs.