The book is a classic reference on airfoil sections and includes a substantial amount of data for different sections. Just because the data is old, doesn't mean that it isn't useful, nor that the theory behind it is flawed.
It was (and still is) a required text in the Naval Architecture and Marine Engineering program at the University of Michigan - where I got my naval architecture degree.
The data is presented in terms of Reynolds numbers, which take into account both speed and viscosity. Doesn't matter what fluid the foil is in.
We were talking about foils in water, not foils in air. Besides, hang glider wings and sails are not foils. They are camber lines.
You have a better reference text, Wouter?
