Quoted from Ericpinballfan:
Your supposed to shot the poor boats and jet ski's?
Fresh water fisherman hate jet ski's and speedboats raising hell while they are trying to get the fish to bite, and enjoy a cold beverage. I imagined torpedoing them before I ever saw that video mode. I guess that is a common fantasy.
A perfect 20 out of 20 will give you between 42 and 42.5 million points. (The boats are worth a bit more than the jet skis.) You can also set the video mode to award extra balls instead of the default setting of a free game. The setting change should be noted when comparing high scores.