“I can almost imagine I can hear the music of that band,” I exclaimed. “The optical illusion is perfect.”
“It has to be,” rejoined the lieutenant. “If the image were in the least distorted or out of perspective, we couldn’t aim straight.”
“What do you do when the periscope is wet with spray?” I asked him.
“Wash the glass with a jet of alcohol and dry it from the inside with a current of warm air passing up and down the tube. A periscope-tube is double: the outer one passing through a stuffing-box in the hull, and the inner tube revolving inside it. The old-fashioned single tubes were too hard to revolve and the resistance of the water used to bend them aft and cause leakage. We can raise and lower the periscopes at will, and all our larger boats have two of them, so that they can keep a lookout in two directions at once, besides having a spare eye in case the first is put out.”
“What are those two little things that big naval tug is towing over there?” I inquired.
“The target for our torpedo practice,” replied Lieutenant Scope. “We shall try to put four Whiteheads between those two buoys as the tug tows them past at an unknown range and speed. If you step forward to the torpedo room you can see them loading the tubes.”
As I walked forward it occurred to me that the twenty-odd men on board the X-4 seemed to be moving about inside her with perfect freedom, without disturbing her trim. I mentioned this to one of the crew.
Courtesy of the Electric Boat Company.
Forward torpedo-compartment, U. S. Submarine, showing breech-mechanism of four tubes. Round opening above is the escape-hatch.