For your bottom situation, you can use my book if you want or look up online leaf spring or cantilever beam
stress=(6P/bt^2)*x
P=transverse end load (force at length Y, the tip of the beam)
b=beam width
t=beam thickness
x=distance from the free end of the beam.
if trying to find max stress, x=L=Y (in this case)
the wind force stuff i'll have to try to remember it should be really easy but i forgot how to correlate wind speed to force.
here is a start
http://en.wikipedia.org/wiki/Wind_power
the chart on that link gives you Watts/m^2 if you know the area of the sail calculating the power and force is easy. and if gives you a range of wind speeds