– why can a boat not angle its rudders to move diagonally against the current in a river, the same way a sailboat can angle its sails to move diagonally against the wind?

Question

– why can a boat not angle its rudders to move diagonally against the current in a river, the same way a sailboat can angle its sails to move diagonally against the wind?

In: 1

Answer 1

The shape of the sail produces lift in a manner similar to an airplane wing. The lift (force) is what propels the sailboat forward. I don’t believe rudder shape would allow this to happen.