If a ladder is to be climbed in full equipment, suitable handholds to brace the diver while climbing the upper rungs and moving onto the deck to the place where gear will be removed are necessary for safety. This also applies if the divers need to climb down a ladder wearing dive gear, and they may need to turn round at the top of the ladder. In the general case, the vessel will be moving in a seaway while the diver is boarding.
