[_yb2s]

Sure, the analogy is loose, but as a sailor myself, I think it fits the fundamental ethos- one works the natural forces against each other to get where they are trying to go- wind, tides, and both aerodynamic and hydrodynamic lift.

The fact that one has a number of force vectors in varying directions with both sailing and solar sailing, both let you work them together in unison get where you want to go.

Quite often when I am "sailing" the wind is light or dies, and I go to "windward" by timing the currents, and wind at best lets me position for the right currents, but below a sufficient level produces no lift to windward.

[andrewaylett]

Fair, although I think the analogy breaks down quickly enough that it's not necessarily helpful.