Powerful fans on boat, blow to own sails, would this move the boat?

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Powerful fans mounted on a sailboat can create airflow, but their effectiveness in moving the boat differs from natural wind. When fans blow air horizontally at the sails, the boat may not move significantly, while a 45-degree angle could generate some movement, albeit minimal. The airflow primarily pulls the boat in the direction of the fans rather than pushing it forward effectively. Demonstrations indicate that a flat sail does not harness the airflow efficiently, and using the fan to blow air backward would be more effective for propulsion. Overall, while fans can create movement, they do not replicate the dynamics of wind on sails.
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A sail boat got stuck because there is absolutely no wind. The boat happens to have some powerful fans. Which are then bolted on deck and blow to the sails.

Would that make the boat move?
  1. When the artificial wind direction is horizontal (0 degree)
  2. When the wind direction is 45 degrees.
Would appreciate some explanation because I am not sure about the answers. I think Q1 will not move the boat. Q2 will move it, but in negligible proportions.
 
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Trikenstein said:
Would that make the boat move?
Yes, but not in the way the wind does.
Air drawn into the fan, will mostly pull the boat that way.
The sail will deflect the blown air, and so will push the boat away somewhat, but also along.

To go faster, take the sail down.
 
There are several demonstrations of this experiment with variations, e.g., here.
 
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Hill said:
There are several demonstrations of this experiment with variations, e.g., here.
Thanks for the video suggestion. Now I see the importance of the curve shape of the sail. There has to be something pushing the air backward.

In my thought experiment, I simplified the problem as a person standing on the deck, pushing on the mat with a stick. Obviously the system is in equilibrium within the boat itself and would not move the boat. Kind of demonstrated in the video when the sail is perfectly flat.
 
Trikenstein said:
Kind of demonstrated in the video when the sail is perfectly flat.
With a flat sail you would want to blow at it from the side, at an acute angle of attack, while it is oriented to divert the air backwards. But as already said, you would be much better off using just the fan, blowing air backwards.
 
Trikenstein said:
A sail boat got stuck because there is absolutely no wind. The boat happens to have some powerful fans. Which are then bolted on deck and blow to the sails.
Airboat go fast:
1704158978483.jpeg


Airboat with parachute pulled behind it go slow/zero... :wink:
 

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