Ahhh...go to sleep Steve!

Seriously though, there has been a bit of debate regarding sonar on racing boats to detect animals and submerged objects. There are a few problems:

A) Any sonar sensor would have a hard time getting steady readings on a Mega Catamaran that's thrashing through the waves at 30knots.

B) There's some theory that sonar signals are unhealthy to some organizms in the sea.

After all, if they could detect subsurface iceburgs and growlers with some sort of device you think they would jump on it in a hurry! The closer they can get to the ice field means a shorter trip around the globe.