Airplanes deploy revers thrusters when landing which are basically just shaped metal shields that move into place behind the engines to provide reverse thrust and slow the plane.
But adding a fan on a sailboat is seen as stupid and doesn’t work.
Airplanes deploy revers thrusters when landing which are basically just shaped metal shields that move into place behind the engines to provide reverse thrust and slow the plane.
But adding a fan on a sailboat is seen as stupid and doesn’t work.
The reverse thrusters redirect the air coming out in the opposite direction, so it is like turning the fan in the opposite direction.
A sail catches the air to pull the boat along and some of it bleeds off, but it does not direct any air backwards to propel the ship forward.