That reminds me of: If from the top of your mast you drop a hand tool when
your boat is sailing a 5 - 6 knots where will it land? The answer is right
on you boat. I wonder why? Could the same phenomena applies to a fan
attached on a boat blowing on its sail to provide propulsion?

"Scout" wrote in message
...
like the cartoon axiom which states, "cartoon characters may be unaffected
by gravity and may be supported by thin air, but only so long as they are
unaware of their current, unsupported status."
Scout

wrote in message
ups.com...

Questions like this remind me of the old Popeye cartoons, where Popeye
thows an old bathtub into the sea, and then, whith a shower head on the
end of a pipe, crams it into the drain. viola! Instant water jet! town
pressure on tub forces water through shower head, and instant
propulsion.

Another Idea that looks good on paper.......



wrote:
A question sometimes asked is that if you have a large fan at the
stern on a
sailboat blowing forward into the sails would that propel the boat
forward? The usual answer given is no because the fan blowing air
forward would produce momentum propelling the boat backwards. This
would swamp the effect of an effective wind acting on the sails.
But suppose instead you had the fan in front blowing rearward into the
sails?
In this case the momentum would propel the boat forward. Furthermore by
using the method of tacking into the wind, the wind blowing into the
sails could produce a force with a forward component as well. Then the
acceleration forward should be higher than that produced by the
momentum flow of the fan alone. The speed could also be higher than the
speed of the air created by the fan since tacking into the wind can
give you a higher speed than the wind speed.
Would this work?


Bob