The Bernoulli Principle can be applied to all fluids. This explains how the low pressure is created on either side of the bow, and as water is incompressable a trough would form. However as the vessel moves trought the water this trough is filled with what would have been much of the bow wave, so in effect a smaller bow wave is produced, this carries on and the trough and stern waves are also reduced. Well thats it in a nutshell boffins write really thick text books about this stuff.
