Silentscorp has some great ideas there. I also do these. but with a few changes.
1. I goto battlestations and crash dive at the same thing also timing it. just hit (b)then (c) right after each other. the boat should go down faster.
2. I also do that but a good rule of thumb is test depth plus 50% and that should be your crush depth. And I do an emergency blow to get up a little faster. Better safe than sorry.
4. thats what junks/sampans are for
