Which is...?Even the climax of the boat pursuit has one added scene which adds insight as to why the zodiac flips over Bond's boat.
After Bond throws his anchor over onto the second zodiac - most of which has been 'piggy-backing' over the aft of Bond's boat - 007 immediately takes the steering control and veers his boat hard a full 180 and then just guns the throttle. With his boat now positioned in the opposite direction (to which it was going (and in which the zodiac is still pointing)), the piggy-backing zodiac, with it's propellor still spinning in the water, launces over Bond's boat. The "flipping-over" is a result of the rope going taut after it's fully fed out, helped by the anchor having hooked into the zodiac. The force then rips away the rope attached to 007's boat, freeing it to travel unimpeeded towards the vacation resort.