You can drop through some roofs by laying down, then holding [Left] + [End].

Go under a dock, then lay down and go towards the shore. You can go though the docks this way if you stop in the middle of the dock when you are going through. You can shoot others, but they cannot shoot you.

To get in boats when there is no dock, go the side net and stick your head out of the water. Then press [End] three or four times and you can climb in.

If you can see the underside of a building, you can go though it insteadd of using a door.

If a delay grenade hits a man in the head while underwater, it will kills immediately when it hits and not a few seconds later.

When you drop a satchel charge in the water, it does not have a drop time. It will go straight to the ground when dropped.

Satchel charges go though roofs when underwater.

You can swim thought most roofs that are underwater.