Initially the dive will be held up when a depth of 60 feet (periscope depth) has been reached. At this point the depth will be maintained with the dive planes and the forward motion of the boat. During this time the diving officer will have the chief of the watch pump water in and out of the trim tanks to make the boat neutrally buoyant and balanced. In addition, the captain will probably order a series of checks on all of the compartments of the boat for watertight integrity, and do a check to see if any machinery is making abnormal noises, or if any objects are loose or improperly stowed. Next the captain will probably order a series of extreme diving exercises called angles and dangles, which are designed to discover if anything is still improperly stowed. The old hands take a perverse pride in being able to walk and keep a cup of coffee from spilling during high-angle dives. Now the Miami can get down to cruising.
Maneuvering a 6,900-ton submarine is something that is done with subtlety and a minimum of rapid action. A slow and delicate touch on the planes and rudders is required to prevent unwanted noise. If you desire to change speed, you rotate a knob called an Engine Order Telegraph, which sends an instruction back to the engine room to either increase or decrease the power to the propeller shaft. The lack of precision might surprise some people, as there are only Forward and Reverse, with choices for All Stop, One Third, Two Thirds, Full, and Flank. In spite of this, the precision that you can maneuver the boat with is amazing. In fact, the OOD can order the precise number of propeller revolutions or "turns" required to maintain any speed required.
The one problem with driving a 688I is that it tends to be slightly unstable at some depths and speed settings. This is partly a product of the 688I's hull shape, which is optimized for speed, and partly from the forward placement of the fairwater. Normally only light corrections will be necessary to keep tracking but one must be ready for any situation, including combat maneuvers, which can become downright violent.
Running underwater is, if nothing else, probably the smoothest ride that you will ever know. Once the boat is trimmed and level, there is little or no sensation of motion, and you feel as if you're walking through the basement of a building. There is, in fact, a feeling of being on very solid ground. Very reassuring, and very quiet. In fact, quiet is the name of the game in this business. When the sub is running underwater, nobody raises their voice, slams a hatch, or even drops the toilet seat hard. After a time, you become hushed and silent. So much the better.
Surfacing the boat is an exercise in itself, as there is no more vulnerable time for a submarine. Part of this is because a surfacing boat makes lots of noise: the rush of compressed air from the air flasks into the ballast tanks; the noise of the hull expanding from the decreased water pressure, called hull popping. All this noise makes the boat partially deaf and blind, so special precautions are taken. The first thing the diving officer does is to have the planesmen at the ship control stations bring her to periscope depth. At this point the search periscope will be raised to do a visual check for any surface vessels, as well as sonar listening for any surface or subsurface contacts. Once the captain is confident that all is clear topside, he will order the diving officer to blow compressed air from the air flasks into the ballast tanks to give the boat a slightly upward, or positive, buoyancy. Within several minutes the boat will surface, and the captain will establish a bridge watch up on the fairwater.
Once on the surface, you immediately notice the rolling of the boat in the surface swells. It is an ironic truth that the same hull design that provides such a smooth ride in the depths of the ocean rolls rather drunkenly in a mild surface swell. While it is not particularly uncomfortable, when compared to the amazing stability of the boat at depth, the difference seems enormous. While running on the surface, it is essential that the bridge watch maintain a constant lookout for any surface vessels. Since a submarine is as hard to see as it is, submariners are always concerned about being run over by a rogue supertanker or liner, and are cautious to avoid fishing vessels, especially those using drift nets.
Communications/Electronic Warfare Spaces
The communications shack is located forward of the control room along the port side passageway, and is notable for the security warnings posted on the door. It is incredibly vital to the operations of Miami. Packed into that tiny space is all of the radio transmission and cryptographic gear that is required to send and receive messages, ranging from operational combat orders to personal "familygrams."
The radio equipment covers a broad spectrum of frequency ranges from ultra-high frequency (UHF), high frequency (HF), very low frequency (VLF), and extremely low frequency (ELF). In addition, there is equipment designed to allow the Miami to contact communications satellites, as well as underwater telephone equipment commonly known as Gertrude. Most of the radio equipment is tied to sophisticated encryption gear (called crypto) designed to make it impossible for anyone but an American to read the message traffic.
This particular point has not always been so secure, as the discovery of the Walker family spy ring showed in 1985. For over fifteen years, a Navy petty officer, along with his family members and a friend, helped the Soviet Union acquire the keys to the various crypto systems used by the United States. This meant that the Soviets had access to virtually all our major crypto systems from 1969 to 1985, when the ring was finally apprehended. Since that time the National Security Agency, which is charged with the design and security of crypto systems, has apparently rebuilt the U.S. family of encryption systems and allegedly changed the procedures that allowed John Walker and his family to put so much of our national security at risk.
The most interesting of these systems are the ELF and VLF systems, which are mainly used as command and control systems for submarines. Their special property is that the signals from ELF and VLF systems can penetrate the water to be picked up by the antenna trailed from the port side of the fairwater. More often than not, because of their relatively low rate of transmission (ELF works at about one letter character every fifteen to thirty seconds; VLF is fast enough for teletype communications), they are used to cue submerged submarines to come to periscope depth, and poke one of their communications masts up to get a signal from a satellite or UHF channel.