1inch fir planking is around 3 lbs per sq ft, 3/16th plate is around 7.5 lbs per sq ft. Fir has a tensile strength of 1500 psi steel around 60,000. or 11250 psi for 3/16th plate. Thus 3/16th plate has 2.5 times the weight of 1 inch planking and 7.5 times the strength.
However wood only has tensile strength along the grain, very little across the grain, and in a cold molded fir hull only a third of the veneers has the grain going in any one direction. Steel has equal strength in all directions. Thus in a cold molded one inch thick hull, the tensile strength of wood is slightly over 1/3rd the tensile strength of wood, about 600 PSI. 3/16th steel is roughly 18.5 times the strength of 1 inch cold molded planking. However, in high stress areas, like chain plates and keel bolts, all loads are across the grain, on all three veneers.
There is nothing weaker than a wooden boat, unavoidably!
Now mr Swain, you keep repeating "tensile strength" as this is something of a mantra for you. Your reasoning demonstrates clearly that you have hardly had any engineering education, no real knowledge about engineering design.
Let's for simplicity say that wooden boats are constructed in either of two ways:
a) traditional: planking on frames.
Here the frames contribute very much to the overall strength of the hull. Frame thickness is, for a typical 32-36 sailing boat, in the order of 1"-2", planing thickness maybe 1". Frame distance ~1 ft.
The wood in the frames are othorgonal to the planking.
The overall hull strength is immense, much more than needed for a typical life time of such a boat.
b) cold baked vaneer.
Here a very strong shell is created by having the veneer cross diagonal. The veneer acts as the reinforcement, the epoxy binds it together. As wellknown from wood industry, two pieces of wood glued together is stronger than one of the same size - quoting tensile strength of fir has no relevance at all in this context (fir is not much used in boat construction, by the way ...).
As with all strong materials, this has to be supported by frames, interior etc. It is possible to achieve some strenth in the "shell" (ie the hull) by introducing some curvature, but this is only sufficient for smaller hulls.
Wooden boats have proven to work very well for houndreds of years. The are many sailing boats still sailing being more than 100 years old. In the harbour where I have my boat there are now about five sailing boats older than 100 years. Still sailing.
And BTW, in our harbour there are no (none, zil, nada, ingen) sail boat made of steel. That favourite argument of yours, mr Swain, about hitting rock ... well, as our sailing areas look we regularly hit rock. Often, for many of us usually more than once a year. Still no steel boats ....