National motor boat championships in California.
California, United States of America (U.S.A.).
Title: "National Motor Boat Championship. Two World's records broken as speedsters flash like rockets over the 5 mile course".
Panning L/S of six motor boats speeding over a lake, the lower slopes of some mountains are in view in the distance. Panning shot follows two boats across the lake, the one nearest the camera has 'B-107' painted on the side. Aerial shot of nine boats speeding over the lake, leaving nine trails of foam behind them, the aeroplane swoops down to get a better view of the boats. M/S of speed boats circling an anchored boat. M/S of boats going around a buoy. Various aerial shots of the motor boats speeding across the lake.
Intertitle: "Spitfire VI took first honours ... reaching remarkable speed of 43.67 m.p.h."
Aerial shot of motor boats speeding across the lake, the plane has swooped down low and flies close to the water.