The officers' quarters consisted of four tiny compartments, two on each side of the after corridor. The first two were the mess room and chart room, and the second pair were the cabins of the commander--a lieutenant--and his second in command, an ensign. Behind them was an electric kitchen, and next came the engines, first two sets of Diesel engines, one on each side of the corridor, each of 400 horsepower. These were for running on the surface. Then came four bunks for the quartermasters and last the electric motors for running under the surface. The motors were run from storage batteries and were half the power of the Diesel engines. The quarters of the crew were along the sides of the forward corridor. The floors of the corridor were an unbroken series of trap doors, covering the storage tanks for drinking water, food and the ship's supplies. The torpedo tubes were forward of the men's quarters. Ten torpedoes were carried. The ammunition for the deck gun was stored immediately beneath the gun, which was mounted between the turret and the first batch, abaft the turret. Besides the turret there were three hatches in the deck, one forward and two aft. There were thirty-four men in the crew. Each quartermaster was directly responsible for six men, while the commander and his second were responsible for five each. The men are counted every two hours, as there is great danger of men being lost overboard when running on the surface, and in bad weather they are sometimes counted as often as every half hour. The turret was divided in two sections. In the after part was the main hatch and behind it a stationary periscope, standing about thirty inches above the surface of the water when the deck was submerged and only the periscope showing. There was no opening in the forward section of the turret, but the fighting periscope, which could be drawn down into the interior or pushed up to ten feet above the surface when the vessel was completely submerged, extended through the top. It is with this periscope that the vessel is navigated. The submarine sails at a depth at which the fighting periscope shows about eighteen inches above the surface, while the commander, standing on two iron grips, with his head, shoulders and body in the turret and his legs sticking down into the cabin, keeps his eyes glued to the sights of the periscope, which he constantly turns from side to side to take in all points of the limited horizon. The part of the fighting periscope that extends above the water is a brass rod about two and one-half inches in diameter, while its eye is only three-quarters of an inch in diameter. It is on this tiny opening that both the safety and fighting ability of the vessel depend.