The boats used for the Great Race are custom built identical heavyweight men's eights from KIRS (Kiwi International Rowing Skiffs) in Cambridge, New Zealand. The nature of the river creates a highly technical course, with the current frequently switching from side to side of the river over the length of the course. This creates an advantage to the team on the side that the current is not on. The current ranges in speed from 0.64 m/s to 1.30 m/s. The slower water has the potential of slowing down a rowing boat down by 1.5 km/h over the length of the race. The race passes under four bridges along its length.