A police boat crashed into two other boats that were docked on the Potomac River in D.C. on Saturday. According to a police spokesman, the cop driving the boat just misjudged how close the other two boats were.

There's video where you can see him making a quick U-turn, then he guns it and sideswipes both of them. And one of the boats was damaged enough that it started sinking.
http://youtu.be/C-r7eEfcV2s