But the crown jewel of the U.S. mine arsenal has to be the Mk 6 °Captor mine. This is an encapsulated Mark 46 torpedo, programmed to wait for enemy submarines; when one is detected the torpedo swims clear and attacks the sub. As an added benefit they can be programmed to listen for a certain type of submarine, like a Kilo or Akula. During the Cold War, it was planned to seed Captors along all the transit routes used by the submarines of the Soviet Union. Now they can be used against any of the growing number of countries that have chosen to buy and use diesel submarines in their navies.
One of the nice things about mines is that they take up only about half as much space as the other types of weapons a sub might carry. Thus a 688I could carry as many as forty mines and still have a couple of ADCAPs for self-protection. The deployment of the mines is no different from loading and firing a torpedo (the BSY-1 has a mine launch mode), though the position of the mine has to be plotted absolutely accurately, so that it can be swept later. Fortunately the advent of GPS has made this task a bit easier, though efficient use of the SINS system is also required.
All in all, these weapons make for a very dangerous quiver of arrows for the submarine force.
Escape Trunks/Swimmer Delivery
Wandering aft about 25 feet from the enlisted mess puts you underneath the forward escape trunk. This is a two-man air-lock used for a variety of purposes, though primarily as the main entry point to the forward part of the boat. It is composed of a pressure vessel about 8 feet tall and 5 feet in diameter. At both the top and bottom is a hatch capable of standing as much pressure as the actual hull of the boat. Most often personnel and supplies are loaded through this trunk. There is also another trunk farther back over the aft machinery spaces.
In the event of an emergency the escape trunk comes into its own. If the boat is on the bottom and stable, the normal procedure is to wait for one of the deep-submergence rescue vehicles (DSRV) to be transported to the rescue site. The DSRV then comes down and docks to the collar over one of the escape trunks. It blows out the water from its own docking collar, now held in place by the pressure of the surrounding water. The crew of the DSRV open their own bottom hatch and enter the downed boat through the trunk. Now the crew of the downed sub can come aboard, albeit only about two dozen at a time. This means that if a Los Angeles boat were to go down intact with all her crew alive, it would take something like six trips to get them all off.
If the boat is flooding and the crew must get off immediately, the escape trunk takes on a more vital role, allowing the crew to escape from the boat under their own power. This is done using a Steinke hood, a combination life jacket and breathing apparatus that fits over the head of a sailor. Two at a time the men enter the escape trunk wearing their Steinke hoods. They close the bottom hatch and huddle under an air bubble flange installed in the trunk for such operations. The sailors then charge their Steinke hood air reservoirs from an air port in the side of the trunk, and open a flood valve to fill the trunk with water. While they sit under the air bubble flange, the upper hatch opens. If they are the first ones to escape from the sub, they will have the additional job of pushing a life raft out of the hatch; this floats to the surface and provides some shelter for the men when they get there. Then, one at a time, they duck under the flange and float up through the hatch.
At 400 feet (the maximum depth that the hood can be used), the men will have something like a minute to flood the trunk and get out. Any longer, and they risk getting "the bends" (small bubbles of nitrogen gas that form in the blood) as they rise to the surface. After they have exited, the controller in the area below the trunk closes the hatch via his control panel and begins to drain the trunk for the next pair of escapees. Meanwhile the two sailors literally rocket up to the surface. This would be extremely dangerous (the decreasing water pressure makes them vulnerable to a variety of air embolisms if they hold their breath), but with their heads in the air bubbles of their Steinke hoods, the men are able to breathe normally throughout the ascent to the surface. Once on the surface, they try to inflate the raft and stay together.
One of the other primary uses for the escape trunk, this one far less ominous, is as an airlock for divers and special operations teams. One of the little-known facts about U.S. submarines is that they have, at all times, a small team of divers (usually three to five rated divers) aboard to support the operations of the sub. The diving equipment and other gear is stored in the compartment forward of the torpedo room, near the VLS support equipment room. The divers' jobs include everything from clearing fouled propellers and running gear, to running security checks on the boat before she leaves harbor. In fact, when the Miami is in a foreign port she is not allowed to leave the harbor unless she has at least three divers aboard to assist in examining the hull before she gets underway.
The other type of diver-related operation that is conducted through the escape trunk is submerged "lock-out" of special operations teams, such as the U.S. Navy's elite SEAL teams. These kinds of operations are really not the forte of the 688I and will, until they are retired, be predominately the job of modified Sturgeon-class boats like the Parche (SSN-683). Part of the problem is that the Los Angeles-class boats are optimized for speed and are not properly equipped to conduct this kind of mission effectively. Also, the already cramped accommodations of the 688I make it necessary to set up temporary sleeping quarters for the team, perhaps on bunks down in the torpedo room.
In the unusual case of a special operations mission, the boat nears the target of the team and hovers over the seabed. The team then enter the trunk two at a time under the air bubble flange, and follow the same procedure as escaping sailors except with their diving gear. Retrieval is exactly the reverse, with the team reentering the trunk two at a time, closing the hatch, draining the trunk, and exiting through the bottom hatch back into the boat.
The Sounds of Silence — Acoustic Isolation
Silence. That is what has made American boats better than their opponents for over thirty years. It is their armor and their cloak all wrapped up into one vital quality. Nevertheless it comes at a high price and is called a fragile technology-fragile because it is based upon well-understood principles of physics, and because it can be compromised so easily. In terms of military technology, it is one of the crown jewels, in the same category as the ability to build stealth aircraft and nuclear weapons. So effective has this silencing effort been that the latest U.S. SSNs and SSBNs are so quiet, they can effectively disappear in the ocean's background noise.
To make a quiet submarine, the naval architects must take a holistic attitude to the design of the boat and every piece of equipment that goes into it. The key is mounting each piece of equipment that moves or makes noise on something that damps out the vibrations. The transmission of these vibrations-things like the spinning of a pump or the hum of a generator-sends noise out into the hull, where it is radiated into the water. In addition, the rubber decoupling tiles coating the hull help keep noise inside the hull from being transmitted out into the water.