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.
For what it’s worth, a thrust reverser is also a very inefficient deflector of air. It’s better than nothing, and jet engines produce a lot of thrust, so even inefficiently reversed it still provides a significant amount of reverse thrust which happens to be quite useful for slowing down an aircraft when there’s minimal weight-on-wheels or on slippery runways, but it’s still only a tiny fraction of what the engines produce in normal operation for forward flight.
A fan blasting air at a sail is also quite inefficient, but as other comments note, it does technically work. It just works so poorly for the amount of energy you’re putting into the fan that you’d probably be better off rowing or just using the sail properly.