The story goes that Sprint boat racing got it's start in New Zealand in 1970 with Marathon river racing. Then in the early 1980's, Brian Scott and some of his buddies came up with the idea of racing boats in a manner similar to automotile rally racing where a navigator and a driver work together around a set track. Ultimately the sport migrated to Australia where the idea of building permanent tracks instead of using rivers or temporary channels developed. Channels about 3 feet deep and 12 feet wide were dug and filled with water. Each race has a set track rotation for that day's racing and the navigator is responsible for directing the pilot around the course.
The engines in the boats range from 500 horsepower to well over 1,000 horsepower in the Superboat class. There are three classes, Superboat, Group A-400 and Super Modified. These boats approach straight-line speeds of up to 80-plus miles per hour and with their incredible turning capabilities can pull 3-7 g's in the tightest corners. The ability of these boats to make 90 degree turns was amazing to me! You can read more about the history of the sport here.
The track here in Tangent is called "Field of Dreams". It sits in the middle of a grass seed field right next to the I-5 freeway. I'd estimate that the total size of the track is roughly the size of 50 yards by 100 yards. There is a chain-link fence all around the track and the spectators site behind the fence not more than 20-40 feet from the channels, just out of reach of the plumes of water that the boats create when making these tight turns. There were 3-4 "wipe-outs" during the day, with one boat actually going part-way through the fence into the stands. Fortunately, nobody was hurt, but it was pretty exciting to watch! The safety features on the boat work well.
This is a video clip taken near the place I was sitting. It will give you a little idea of my perspective. The announcer's stand was about 50 feet to my right.
Here are some pictures I took with my cell phone. Not that great really.
Here's a link to much better pictures of boats.