Unter detaillierten Prozedurbeschreibungen ist das dann auch begründet:

"Avoid a landing flare because of difficulty in judging height over a water surface. It is expected the airplane may skip clear of the water once or twice using the optimum technique outlined. If final contact is made in the desired level attitude, the airplane will experience two or three seconds of moderately abrupt deceleration, and then will float for only a short time."