"markvictor" wrote in message
oups.com...
3721 mph, but that would be in a submarine, not on the surface, at sea
level, the nasa standard table puts SOS at sea level in daytime at
761mph...so that is what a surface vessel would have to achieve to
break the sound barrier; even a displacement hull is still floating on
the surface of th water, so it wold be subject to gas physics.A boat on
the surface is exerting a fixed force on the water (in a perfect
world), this force remains more or less constant, varying onle due to
lift and loss of it while moving, this will not generate a fast enough
shock wave through water to cause a "sonic boom"


741 mph in air at normal sea level pressure. In water at the surface, and
for a long ways down, the density does not change much, the speed of sound
would be 3000+ mph. Is why when diving, you can not tell which way a boat
or sound is coming from. Ears, are not built to differentiate the time
difference between the ears at those speeds. Air gets out of the way at
supersonic speed, or the plane could not get through the air above the speed
of sound. Sound is a pressure wave, and at the speed of sound all the
pressure of the sound waves, piles up on the plane. So lots of buffeting
and control surfaces lack response. Above the speed of sound, the
pressure wave falls away from the plane to the rear. Similar to the bow
way, now that I think about it. You have to climb the wave,and after you
start to plane, you have left the bow wave behind. Takes power to overcome
the bow wave pressure, but once on plane, you would require less power to
stay on top. Of course to get on plane, you have to use enough power to
lift the boat vertically some distance.