Sailboats and Fans
Most recent answer: 10/22/2007
- Mark (age 50)
S. Salem NY
Pointing a fan mounted on the back pointing it straight at a sail whose surface is perpendicular to the air coming from the fan. This is very ineffective, as the fan pulls the boat backwards by shoving the air forwards, and the sail pulls the boat forwards with almost the same force by stopping the air again. The boat may not stay exactly stationary, but it sure wont make much progress.
The best way to do this is to remove the sail entirely, and point the fan so it blows air backwards. Then the boat feels the full reaction force pushing forwards. This is how those swamp boats work.
(published on 10/22/2007)
Follow-Up #1: put boat fan in water?
- Brad Howell (age 52)
Those are electric fans. It's not such a good idea to put them in water. At any rate, their speed, blade size, etc. are designed for air, not water. Underwater propellers also work well, but they aren't the same design, And they don't have open electrical connections to short out.
(published on 10/05/2013)