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The old Guppy III Amazonas (ex-USS Greenfish [SS-351]), which the author commanded, is still doing her job. She is to remain in service until all Type 209/1400s reach the fleet.
The 1-mc announces twice: “Secure snorkel.” The whole atmosphere heats up and crewmen sense sudden pressure as the vacuum drops. Silence returns after the last hull valves close, and the boat has a “down bubble” until reaching the safety depth.
The officer on continuous watch at the search periscope can finally rest eyes affected by the fog and the smoke from the exhaust mast caused by a big wave Washing over the submarine. The engine quartermaster may now remove his uncomfortable ear protectors and wait for the diesel engines to cool down so that he can carry on with minor repairs and maintenance.
The sound room returns to normal manning, searching for surface and submarine contacts—especially in the rear blind arc. Sonarmen are not happy when the submarine’s safety depends only on an electronic support measures (ESM) mast—effective only against surface ship and airplane radars that provide good signatures—that leaves the whole underwater environment uncovered.
Slow-speed diesel boats demand extra endurance from the crew during long transits to distant patrol areas; the tiny accommodation and recreation spaces begin to create a serious problem after the first two weeks at sea. Physical fitness drops and crewmen start to gain Weight. Fresh vegetables and fruits disappear from special low-calorie diets after three weeks at sea, and those who smoke find in cigarettes their greatest pleasure—to the discomfort of their shipmates.
The lack of sunlight disturbs the crew’s metabolic pattern; reading becomes a common hobby, especially before going to sleep. Recent studies have identified some vertebral column problems in submarine crew members caused by abnormal bulges in bunks where books and other personal belongings are put away below the mattress. The night Watch, especially for the captain, is never quiet. His small cabin is filled with reports over the muted 1-MC; a dimmed ted glow illuminates the gyro repeater and depth gauge, and sometimes a bubble indicator and altimeter to register pressure or vacuum on board.
The captain never quite attains deep sleep; sometimes he is called to the Periscope during the night, and his eyes must remain constantly dark-adapted, since most of the time he has to take a
quick look through the periscope to make a decision regarding a short-range surface contact. There is rarely time to adjust dioptry or interpupillary distance properly, which causes additional eye strain.
Seals sometimes fail to keep the diesel- engine exhaust gases from leaking. If the seals leak only during the engine start as the pressure builds up at the exhaust duct to expel the sea water, smoke will be present for just a few minutes. But if it happens while snorkeling, it may become hazardous, for the carbon monoxide partial pressure may reach dangerous levels immediately after securing from snorkeling, when ambient pressure rapidly rises. An extra rest period for the whole crew is sometimes provided by lying on the bottom in shallow waters. Of course, that puts the submarine out of touch with the outside world.
Tactical conditions permitting, some contact can be maintained when operating near shore or with surface forces by using helicopters to deliver mail at night. Completely isolated from the real world, submariners suffer severe social constraints for weeks. Military pilots may experience the feeling for a few hours, but very seldom for even a whole day.
Surface warships are faster and roomier than diesel submarines and they normally travel abroad frequently, providing motivation to their crews on visits to foreign countries. Diesel submarines always participate in secondary deployments with antisubmarine warfare forces that keep them close to their home bases since their speeds of advance are too slow.
When submarines do travel abroad, they get underway several days ahead of the fleet, sometimes exposed to very rough transits at high speeds at short snorkel cycles. There are fewer officers and enlisted men to stand harbor watch on submarines, which further restricts opportunities to go ashore.
Many other factors make recruiting for the submarine service an increasing challenge to navies nowadays. NATO navies have experienced problems related to motivation in recruitment, especially during the Falklands Conflict, where diesel boats were fully employed on extended patrols far from their home bases. Extra pay along with improved facilities ashore have proved the only way to minimize recruitment problems. In Latin American navies it has been observed that enlisted men, who spend repetitive tours on submarines, age rapidly in comparison to officers—who normally do not exceed a maximum continuous period of three years on board.
Recruitment difficulties also stem from the very rigid prerequisites concerning physical and psychological health and the initial escape training accomplished in submarine school. After the basic phases of the course, many student submariners, though judged fit for service, do not feel comfortable on board as trainee. It is even more difficult to recruit specialists like sonarmen and enginemen.
Small submarines really require twin crews because the complement is too small to account for leaves and other natural absences; this further compounds recruiting difficulties.
Shore-based trainers are necessary because submarines with small crews can
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accommodate only two to four extra crew members. Dive training provides a good example; it is not restricted to new submariners since requalification training is required for those who are moving from one class of submarine to another. In addition, it makes no sense to jeopardize the safety of the crew by simulating emergencies on board the submarine. Such trainers are invaluable.
The main point in qualification concerns officers. To qualify for command of a submarine after 15 years of intermittent duty on board submarines, the officer must prove himself self-confident and able to handle the stress imposed by operating under severe conditions that may require one or two days without sleeping and multiple inputs to solve.
The big difference between submarine and surface ship captains stems from the nature of the submarine: at periscope depth, where all sensors are available for the attack, he is the only man on the attack team who sees the target, records its angle on the bow, range, and speed, and distinguishes it from among the rest of the surface contacts—fishing vessels, merchantmen, or speedy ASW escorts. In contrast, combat information centers on new surface vessels provide vital information to all the members of the team, not just the captain.
Quick mental gymnastics used by the captain immediately after lowering the periscope provide the quickest way to update target parameters, and in fact are faster than a computer. The result is that the submarine captain rarely has the opportunity to share his decisionmaking with his officers.
The relatively slow speeds of submerged diesel boats require very specific tactics qualifications; mistakes can rarely be salvaged, and there is little chance for a second shot. Incorrectly calculating the target’s speed is enough to put it outside of the torpedo envelope as the target steams by.
The stress problems on a submarine increase throughout an officer’s career, and culminate while in command. Life on diesel boats is harder than it is on nuclear-powered submarines because of limited power available and limited space. The need to snorkel during reasonably short periods generates noise, smoke, and increases the risk of flooding through hull valves; it is aggravated by poor sonar performance. Pressure changes also disturb the body if continued.
Submarine officers begin training for command early, right after submarine qualification, when lieutenants not only have the opportunity to maintain the submarine’s precise depth through correct trimming but also take part in attacks, manning manual plots during periscope or blind attacks.
Subsequently, officers attend a series of modular courses to qualify for periscope watch, attack team coordination—submarine advanced course, and finally the command qualifying course, which depends on a formal proposal by the promotion committee.
This course is divided into two major periods. The first one checks whether the prospective captain is tactically proficient at periscope depth in a multitarget scenario of fast warships combined with other common surface contacts, such as fishing vessels and merchant ships. Any weaknesses are detected during advanced exercises when the student is pushed towards his limits.
During the second period, tactical situations are generated that include all ASW threats—helicopters, ASW frigates, ASW maritime patrol aircraft, and other submarines. The cost is high, and the second period is normally included in regular fleet operations where each student is given a period in command.
Vital to safety and good tactical performance are the tactical simulators ashore that allow a satisfactory degree of training before going to sea.
Modem submarines tend to operate for three years before undergoing a six-month refit. High-performance batteries permit extended operational cycles. Small submarines, although almost totally automated, require advanced qualification for ship maintenance as well as highly specialized workshops ashore. Submarine shipbuilders are not the best to carry out these refits, and neither are shipyards dedicated to surface-ship repairs. Submarine bases themselves have the manpower; personnel can be qualified and can dedicate their attention to the unique requirements of submarines.
Navies with fleets of small submarines should be prepared to move supplies to wherever the submarines happen to be. Despite the initial investments, containers are the best solution, because they increase the flexibility to be moved abroad by cargo aircraft.
Black-box technology makes the combat power of submarines very dependent on other countries. Sophisticated systems can turn into junk if spare parts are no longer available or equipments are discontinued without prior agreements between nations. The major problem consists of matching different equipments of many nationalities in order to get the correct interface.
Prototype systems are always a risk but they assure a private access to technology that may be vital when developing tactics.
U.S. submarines provide a good example of standard logistical systems: USS Los Angeles (SSN-688)-class nuclear- powered attack submarines still carry some of the same equipment that proved reliable on older Guppy or even fleet-type diesel boats. Emergency lights, bilge flooding alarms, interior communication, and even some transducers have survived for four or five decades.
Conventional submarines will survive for years in friendly partnership with nuclear boats because of the need for balanced power among nations that are still developing nuclear propulsion. Strategic scenarios on the same continent make diesel submarines useful and less expensive.
Even the old U.S. and Soviet submarine fleets, which had typical overseas characteristics, have maintained conventional and nuclear-powered submarines for decades, keeping mothball fleets in different bases. Diesel-boat designs that contributed to nuclear-powered submarine designs were never sold to foreign countries outside NATO.
The present world economic crisis is forcing reductions in nuclear-powered submarine fleets. Geographically restricted scenarios still use conventional submarines, which incorporate modern technologies that allow them to remain submerged for long periods at faster speeds as quietly as any other submarine.
Modern wire-guided torpedoes make attacks possible from greater ranges, compensating for the slow attack speed provided by batteries even at very high discharge rates. Surveillance at periscope depth gets more effective as low-light television and infrared technologies are used in combination with ESM warning, minimizing snorkel “indiscretions.”
Finally, small diesel boats are much more capable of navigating safely close to shore to launch agents or combat divers. They may explore depths where active sonars are basically ineffective, concealing themselves in shallow waters.
Diesel boats were the primary school for submariners and still provide a reliable and inexpensive combat power to navies that cannot fully use nuclear-powered submarines. Recruitment and training of crews, keeping motivation at the highest level demands continuous attention, for the crews are the real treasure of a submarine force in any navy.
Captain Biassio Miro is the chief of staff of the Brazilian Navy’s submarine force. A submariner since 1974, he was the executive officer of the Tonelero (S-21) and commanded the Amazonas (S-16).
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