A common way for powerboats to sink is to take water
over the stern. A couple of easy ways to do this, especially on outboards with low transoms.
If the boat comes off plane quickly the stern wave can catch up and dump water in to the transom, which weighs the transom down, allowing more water to enter.
Another way is to back up quickly, the stern buries and water pours in over the transom, weighing it down and allowing more water to enter.
Backing into a wave or slowing down too quick with a following sea, just makes it worse.
Some Mako's and Steigercrafts are prone to this problem.
A few years ago during a large festival in a harbor, a hotshot in his big overpowered speed boat was showing off in front of the crowd. Had the hood
open to cool the engines and threw the 4 engines into reverse, the stern buried, water flooded the engine
compartment and down she went stern first. Sat there for a day with the bow pointed skyward and the stern on bottom before it could be salvaged.