Quote:
Originally Posted by BernieP2
Sub in water works the same way (I think!?)
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Yes and no. I assume that "dynamic lift" involves moving forward at an angle that generates lift.
A sub in the water has to be balanced in a daily test dive. It was possible to come close to neutral bouyancy, but almost never perfectly. This is achieved by pumping water in the trim tanks until the boat is balanced as close to perfectly as possible. Once done you should be able to dive the next time without worrying. Problem is that by "the next time" you have expended fuel, making the boat lighter, people have eaten, which makes the boat lighter, if only by a few pounds. So on every dive you have to adjust for that. And now the clincher: every boat, every ship, no matter how "watertight", leaks. The more time you spend underwater the heavier the boat becomes. The only way to handle this is by moving quickly enough that the dive planes can respond, which makes you noisier, or by using the pumps to adjust the trim or pump some water overboard, which is also quite noisy.
There is no compromise, the boat is never perfect, and you have to deal with it somehow, and that almost always involves making noise, which is what you don't want.