There are also several instruments in the conning tower and among these is a _depth meter_, that is, a device that shows just how far below the surface of the water the boat is. An _inclinometer_ which points out the angle at which the diving rudder, or hydroplane is set, and a _tell-tale_, that is a bank of miniature lamps, each of which is connected to a detector in a compartment. Now if the boat should spring a leak the detector closes the current and the lamp is lit. Then there is another electrical system that closes all the bulkhead doors by electricity. The instant the tell-tale lamp lights up and shows that a compartment is leaking the commander presses a button which rings a bell in it and this warns any of the crew who may happen to be in it to get out; by throwing a switch the current operating the motors which work the bulkhead door is cut in and the door is screwed down watertight. Should a shell put the conning tower out of commission the boat can still be steered from the navigating room in her hull. The power plant that drove the _H-24_ was a big 12-cylinder oil burning engine that developed, I should say, about 3,000 horsepower and it worked on the same general plan as a motor car engine. Now when the boat runs light or awash the engine drives her propeller direct and at the same time the engine runs a dynamo and this charges a large storage battery. But when the boat is running submerged the engine has to be shut down because the burnt gases cannot exhaust into the water as the pressure of the latter is too great. A powerful electric motor is coupled to the propeller shaft and this is energized by the current from the storage battery. The ballast tanks into and from which water is pumped to make the boat sink and rise is in the middle of the bottom of the hull. The torpedo room is for’ard in the bow of the boat, our sleeping quarters aft of this and my wireless room lay between our sleeping quarters and the navigating room. While life on the submarine was not exactly what you would call a pleasure bout still we were all keyed up to the point where we wanted to get in our fine work on the _boches_. Finally the time came when we received orders to move and while only the officers knew where to or for what purpose at the time of departure we were all let into the secret after we had got under way. At the beginning of the war the Germans had vessels of various sizes in all parts of the world. Those that were in our ports were interned while some of the smaller ones that were at sea became pirate ships, technically known as _raiders_. They flew the flag of Germany when it suited them to do so but they hoisted any flag that would best help out their diabolical plans.