Except in the West Australian pearl fisheries most of the world's diving is done in shallow water, from small boats or piers; and in civil life each diver is independent and controls the situation according to his own lights. In the British Navy the divers work under an officer who directs all the above-water side of things, such as the arrangements for pumping down air, and deciding whether or not it is safe to dive in existing circumstances. Though the officer will have had a short training at the Naval diving school he is not necessarily experienced in under water work; but he will be a seaman possessing knowledge of boat management, weather, and tides, with the authority to give and enforce orders which the young diver lacks. For simple shallow water work the first system is probably the better, though hardly practicable in a disciplined service where the divers are recruited from the lower ratings.