INTRODUCTION
This article attempts to describe the difference between the two (2) submarine battlespaces in the littoral zone and open ocean for diesel electric submarines and nuclear attack submarines, and the inherent environmental factors in an arena of underwater warfare for type submarine that can be exploited to one’s own advantage by cognizant naval commanders. This research work by the author is based on various reading materials particularly from the US Naval Post Graduate School in Monterey, California, lecture notes during my student days in Post Graduate Study in Submarine Design, Department of Naval Architecture, University College of London, United Kingdom of Great Britain in 1991 and also from various reading materials in defense review magazines.
LITTORAL ZONE SUBMARINE OPERATIONS
Submarine operation in littoral zone operation is a contested environment similar to the Archipelagic coastal waters of the Philippine seaward portion and is predominantly considered as confined and shallow waters (with depths less than 200 meters), narrow straits, jagged and rugged coastlines, tidal areas as well as extensive seabed flats, underwater hills and mountains, shoals, and river estuaries. Furthermore, it also includes the landward coastal inland human activities in which submarine sensors pick-up signals that could significantly affect target information reception and be regarded as a very specific operational environmental risk associated with heavy maritime traffic and prevailing variable climate conditions that affect sound projection of sensors in the conduct of military operations.
In summary, it is a cramped, congested and contested operational environment which is extremely complex, thus, the challenging littoral zone underwater battle zone arena of conflict affects freedom of movement with various threats and risk. However, such a broad range of limitations provide some opportunities for submarine cognizant commanders to swing these opportunities to their own tactical advantage.
OPEN OCEAN SUBMARINE OPERATIONS
Deepwater is ideal for submarine operation because it is the opposite of littoral waters in that submarine operation has no limitation in terms of space, time and environmental factors, and offers a wide spectrum of underwater battlespace for submarines with a high level of maneuverability, speed and acoustic sound propagation that is almost perfect to enable cognizance of an incoming deliberate attack.
TWO TYPICAL TYPES OF SUBMARINES IN WORLD NAVIES
The common types of submarines in the inventories of various Navies of the World are the Diesel Electric Submarine and the Nuclear Attack Submarine.
- Diesel Electric Submarines (SSN) – A small to medium size conventional submarine between 150 to 1,640 tons displacement propelled by diesel electric propulsion unit.
Dolphin Class Submarine
Displacement: 1,640 tons surfaced and 1,900 tons dived
Dimension: Length 57.3m (188 ft)
Diameter 6.8m (22 ft. 4 inches)
Draught 6.2m (20 ft. 4 inches)
Performance: Speed 11 knots snorting and 20 knots dived, range 14,825 km (9,120 miles) at 8 knots surfaced 780 km (485 miles) at 8 knots dived
Diving depth: 350m or 1,150 ft operating depth
Torpedo Tubes: 6x533mm (21 inches) and 4x650mm (25.6 inches) tubes all bow mounted
Electronics: Elta Surface Search Radar, CSV 90 active/passive hull mounted SONAR, PRS-3 passive imaging SONAR, ISUS 90-1 torpedo fire control system and Tinmax x 4 CH(V) 2 ESM
Target: Hostile surface ship and submarine of high military value
Complement: 30
- Nuclear Attack Submarine
Displacement: 7,800 tons dived
Propulsions: 1 x General Electric S9G Reactor supplying steam to 2x steam turbine delivering 29,825 kw (40,000 shaft horse power) to one shaft to a pump jet propulsor
Performance: Speed 34 knots dived and endurance unlimited
Armament: 4 x 12 inch (533 mm) tubes for 26MK 48 ADCAP Mod 6 wire guided torpedoes and/or Harpoon Anti-Ship Missiles or MK 67 Mobile and/or MK 60 CAPTOR Mines, and 12 Vertical launch system, tubes for 12 Tomahawk land attack missiles with nuclear warhead.
Electronics: 1 x BP S-16 Navigation Radar, 1x CCSM combat data system, 1x WLX-1 Acoustic Countermeasure System, 14 External, 1 Internal Countermeasure launch, an advance SONAR Suite including an active/passive array, 2x passive wide-aperture flank array active keel and fin arrays, TB-16, and TB-19 towed array.
Target: Carries weapons of mass destruction for deterrence and to neutralize other surface vessels and submarines of high military value.
Crew: 134
ASSESSMENT
A very small or medium-size diesel electric submarine is a very quiet submarine and capable to hide with natural underwater concealment, blended with natural underwater terrain. Said submarine can operate underwater using only batteries to supply power to the entire submarine’s ship system which emits negligible sound, undetectable by surface ship sensors.
Said submarine is very difficult to detect because SONAR sound propagation of anti-submarine surface ship is being significantly affected by environmental factors, hence, sensor reception of the returning echo to the sensor receivers make it difficult to conclude a deliberate anti-submarine attack.
A huge nuclear attack submarine can also operate in littoral zone during peace time situations, but said type submarine is risky to dive deeper to evade anti-submarine surface ship attack in times of conflict because of its large volume of hull structures. It should not take unacceptable risks of grounding and colliding with undersea terrain.
Nuclear submarines can be easily detected in littoral zones because of its huge body volume of displacement that creates disturbances in the surrounding underwater environment. Aside from this, it is quite noisy and constantly emits acoustic noise from her pumps continuously operating to supply seawater to her cooling system for her nuclear reactor in order to prevent meltdown.
CONCLUSION
The most feared adversary of naval commanders is the submarine as it is not visible at the surface of the sea in areas of conflict.
Stealth is an important attribute of a submarine. However, when the presence of a hostile submarine is detected, her invincibility is lost and the effective use of her weapons system is denied. So, instead of being the hunter she now becomes the hunted.
A poor Navy that possess an inventory of a diesel electric submarine can provide a force multiplier to her fleet in the areas of conflict in contested waters, and can provide fighting capabilities for gaining sea control in the arena of a contested environment.
REFERENCES:
- Robert C Jackson, The Encyclopedia of Warship (2006).
- Dajun Tang, James N. Moun, James F. Lynch, Phic Abbot, et al., Shallow Water Acoustic Propagation (2007).
- Prospective Operation in Confined and Shallow Water, Study Paper, Kiel 2015, COE CSW Study Paper (1st Edition)
- Charles H. Sinex and Robert S. Winokur, Environmental Factors Affecting Military Operations in the Littoral Battlespace, Johns Hopkins APL Technical Digest, Volume 14, Number 2 (1993).
- Victor G Ristvedt, Commander USNR, Conventional Submarine Threat in Littoral Regions. Sonar Propagation (1993), https://fas.org/man/dod
- Littoral Operations in a Contested Environment (http://www.marines.mil)
- Photo credit: The Walrus by Nathan M. Greenfield, April 2015 / Featured Under Pressure: In defence of Canada’s submarines, Updated Apr. 10, 2020 | Published Apr. 23, 2015.
About the Researcher/Editor:
CAPT TOMAS D BAINO PN (Ret) completed his post- graduate studies in Submarine Design at the Department of Naval Architecture, University College of London, United Kingdom of Great Britain under the sponsorship of educational grant of UK Ministry of Defense. Capt Baino is a contributing member of the Editorial Board of Marine Review, providing series of articles in Naval Ship Design; and served as Naval Architect Consultant with the Department of Transportation and Philippine Coast Guard Project Management Office in Ship Acquisition Program from 2017 to 2020.