I should start by saying that yes this is a dangerous race and those adventurous men (and I noticed a few women in there) take their chances, but the safety rules and regulations set in place are of the tightest level, there are safety vessels at all stages of the race ready to spring into action if needed. From the time the last kayaker comes through the rapids there is a substantial time lapse before the first of the speed boats comes careening through the gap to allow the kayakers to get well ahead onto the straight. There are times when the advantage definitely goes to the kayaker, for instance last year the water levels were so low due to lack of rain that for many parts of the rapids the boats and kayaks had to be carried, have a look here (Avon Descent 2010) to see the most amazing pictures of last years race conditions. I should imagine that it would be a lot harder hauling a speed boat over rocks than it would a kayak, but... I never intend to find out, how about you.....!!