Does a ship move with its wave, or with the wind that drives it?
Whether ship, wave and wind share one motion, and how a current and wind of equal but opposite power hold a ship still.
A text page without diagrams. Leonardo poses whether a ship travels as fast as the wave that carries it, or as fast as the wind that drives it, or whether it shares in both motions at once. In a second note he reasons that if a mariner has the current in his favour but the wind against him, and the two are of equal power, the ship will stay where it started. The problem belongs to his wider study of how motions combine and cancel.
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Whether the ship shares the motion of both wave and wind
Leonardo asks whether a ship moves as fast as the wave that bears it, or as fast as the wind that drives it, or whether it partakes of both motions together. The question treats the ship's motion as possibly compounded from two separate causes.
Current and wind of equal power cancel
If the mariner has the current in his favour and the wind against him, Leonardo reasons that, provided the two are of equal power, the ship will remain in its original position. Opposed motions of equal strength leave the vessel at rest.