Keeping your motor cool is of the utmost importance in electric boat racing. This will maximize performance and most importantly conserve equipment. A water pickup should be attached either at the trailing edge of a sponson or as part of the rudder assembly. One good way to keep your motor cool is to create some cooling blocks for the brushes as shown in the photos below. A piece of aluminum is threaded to the size of brush housing and an aluminum tube inserted into the "block". Attach your rubber "plumbing" hoses to it and continue it out of the boat. Note the cooling coil wrapped around the center portion of the motor in the bottom photo.

These examples and photos are courtesy of JimClark.