Frogman
From Free net encyclopedia
- This page describes a type of scuba diver. For other uses of the word frogman, see Frogman (disambiguation)
Frogman is a popular term for a scuba diver. The word arose around 1940 from the appearance of a diver in shiny wetsuit and with large fins on his feet. The term preferred by scuba users is 'diver', but the word persists in usage by non-divers, especially in the media, often to refer to professional scuba divers in organizations such as the police.
Usual usage of the word "frogman" implies diving for action, often in combat; such divers are also sometimes called combat diver or combat swimmer.
A few sport diving clubs have included the word "Frogmen" in their names.
In Britain, police divers have often been called "police frogmen". The first British police diver was a policeman who, needing to search underwater for evidence or a body, did not use a drag but went home and fetched his sport scuba gear. See also Ian Edward Fraser.
Some countries' frogman organizations include a translation of the word "frogman" in their official names, e.g. Denmark's "Frømandskorpset" and Norway's "Froskemanskorpset"; others call themselves "combat divers" or similar. Others call themselves by indefinite names such as "special group 13" and similar.
See anti-frogman techniques for details of detecting and combatting unwelcome frogman and scuba diver incursions.
Contents |
Types of armed-forces divers
Military diving is a branch of professional diving carried out by world armed forces. There may be intergrades between combat divers and other divers, such as when naval work divers (called Clearance Divers in the British Navy and Royal Australian Navy) are the nearest available divers to call on to investigate intruding unidentified divers and if necessary use force to arrest them and make them surface; see anti-frogman techniques.
Many nations and some irregular armed groups use or have used combat frogmen.
Frogman training
Training armed forces divers, including combat divers, is far harder, longer and more complicated than civilian sport scuba diver training, typically takes several weeks full-time, and the trainees must be at full armed forces fitness and discipline at the start. It needs much higher levels of fitness, and during the course there is often a high elimination rate of trainees who do not make the grade. For more details see the articles on each nation's frogman group below and their external links.
This contrasts with civilian sport scuba diving training which tends to be one evening a week, being 30 to 60 minutes swimming pool time, followed by two hours or so of dry meeting (often in a social-club-type environment with an open bar). The club's rules allow diving in outside water when the trainee has reached an "open water" standard defined in the rules. The general environment at sport dives is liable to encourage what a naval frogman-trainer would call "a casual tourist-type attitude to being underwater".
Equipment
For scuba diving gear in general, see Scuba set.
Breathing sets
Frogmen's breathing sets on covert operations should have these features:-
- Be a rebreather, because open-circuit scuba produces large amounts of bubbles and noise (both on exhalation, and the intake hiss of the regulator valve as the diver breathes in) showing where the diver is. Also, rebreathers give much longer dive times for the same size of breathing set. There have been experiments with making released air or gas come out through a diffuser, to break the bubbles up; this may sometimes work with the small amounts of gas that are released by rebreathers, but open-circuit scuba releases so much gas at every breath that a diffuser large enough to handle it without making breathing difficult would be too bulky and would interfere with streamlining.
- In any sort of underwater combat a man with a large aqualung has a high rotation-inertia and is very unstreamlined in the twisting and turning involved in fighting and straight swimming, and his maneuvering is slowed critically compared to a man with a light streamlined rebreather with all parts close to his body.
- Be fully closed-circuit, not semi-closed circuit sets that emit a small but steady trail of bubbles, unless it has a diffuser on its blowoff vent.
- Be as silent as possible in use.
- Have a fullface mask letting the frogmen talk underwater is useful.
- Be a dull color to avoid being seen from out of the water; many are black, but the Russian IDA71's backpack box is mostly dark green.
- Contain as little iron or steel as possible, to avoid detection by magnetic sensors; this is also useful when the frogmen have to remove or defuse mines underwater.
- Be well streamlined for long fast swimming. This may mean removing safety features such as a bailout that would add bulk such as would be found on work diver's and modern sport divers' rebreathers.
- Have a long dive duration.
- Leave the front of the frogman's abdomen clear so he can easily climb in and out of small boats or over obstacles, particularly out of the water.
- Its working parts and breathing tube or tubes should be safe from attack in an underwater fight, including in the risk of being "jumped" from above.
- Breathing bags should be toughened against stabbing and scratches, or safely inside a hard backpack box. Older Siebe Gorman-type rebreathers (see Siebe Gorman CDBA) had one breathing tube, which was in front of the chest and easier for the frogman to keep track of.
USA frogmen's rebreathers tended to have the breathing bag on the back before enclosed backpack-box rebreathers became common.
The Russian IDA71 as a frogman's breathing set
The Russian IDA71 is well designed for fights underwater:-
- Its backpack casing is hard smooth rounded metal and has little that can be easily grasped and pulled at. There is no mass of projecting valvework behind his neck to cause hydrodynamic drag and for an attacker to grasp.
- Its only external control is its on/off switch, which is on its right edge near the bottom where he can reach it easily.
- It does have looping breathing tubes like an old-type aqualung, but these originate well apart next to where they come over his shoulders and do not have to reach across from the back of his neck. They can be strapped to the shoulder straps so they do not float up into big vulnerable loops behind the shoulders.
- When the frogman comes out of water quickly, the holes in the casing let contained water drain quickly, so he is quickly rid of the weight of the water.
Open-circuit scuba as a frogman's breathing set
The common sport open-circuit scuba is not recommended for combat action, particularly in a fight against a trained naval or combat diver, because:
- It makes the diver heavy and cumbersome in rolling over and changing course or speed.
- Turning the air off or on is easy for an attacker from above but difficult or impossible for the frogman himself, unless the cylinder or cylinders are mounted inverted. However, that needs more pipework, and it is easy to bump the valvework on things when taking the set off.
- The long trailing breathing tubes or regulator hoses can easily be grasped and pulled.
- The quantity of projecting metal parts around the cylinder top can be easily grasped to pull the frogman about by.
- The noisy bubbling and regulator intake hiss make it difficult to approach underwater unheard, unless the frogman holds his breath, and holding the breath while scuba diving is risky: see diving hazards and precautions.
Combat frogmen sometimes use open-circuit scuba during training.
Masks
Most frogmen use a fullface mask instead of separate mouthpiece and mask. The older type of British frogman's and naval diving mask was fullface and had a mouthpiece inside it. See full face diving mask for more information including requirements if there is a risk of underwater fights.
Some frogmen use a mouthpiece and noseclip or a mouth-and-nose (oro-nasal) breathing mask instead of a diving mask with eye windows, and special contact lenses to correct the vision refraction error caused by the eyeballs being directly submerged. This is to avoid a searchlight or other lights reflecting off the mask window and thus revealing his presence, but it exposes the eyeballs to any pollution, poison or organisms in the water.
Fins
Another problem with a frogman who may have to come ashore and operate on land is the awkwardness of walking on land in fins, unless he plans to discard his kit and return to base by some other way than by diving, or if the frogman plan to take and hold a position until other troops arrive. Some sport diving fins have the blade angled downwards for more effective swimming, but this makes walking on them even more awkward. The usual solution is for the frogman to take his fins off and carry them, but that takes time and occupies a hand carrying them unless he can clip them in to his kit, or thread an arm through the fins' straps. There has been mention of a type of fin with a lockable hinge which on land can be unlocked to allow the fin blade to hinge up out of the way when walking. The first type of British naval swimming fin had a short blade which was even shorter at the big toe side: this made walking on land easier for such purposes as creeping up on a sentry from behind on land, but reduced swimming speed.
Diving suits
The frogman's diving suit should be a tough scratch-and-cut-resistant drysuit (perhaps reinforced with kevlar), and not a soft foam wetsuit. A wetsuit can be worn under the drysuit as a warm undersuit. In very warm water, a thin tough drysuit can be worn with no undersuit. It should not have obvious bright colored patches, unit badges or the suit maker's advertising; but diving sea-police types may find that a unit badge is useful.
Tools and weapons carried underwater
Weapons that can be carried by a frogman include:
- Knife. The standard weapon is a diver's knife.
- A speargun has been seen advertised in circumstances suggesting its use for combat and not for fishing.
- APS underwater rifle and SPP-1 Underwater Pistol.
- Other tools include net-cutters.
Transport for frogmen
Frogmen may approach their site of operation and return to base in various ways including:-
- By swimming all the way.
- In canoes.
- They may be dropped off and/or picked up by fast RIBs.
- In WWII, Italian and British frogmen used manned torpedoes to carry them to their targets. Some nations still keep manned torpedoes.
- The Subskimmer and similar.
- Midget submarines such as the X-craft which frogmen can exit and return to through an airlock.
- Full-sized submarines which frogmen can exit and return to, sometimes through a special airlock, sometimes through one of the sub's torpedo tubes. These two methods, like all methods, need precautions: this link (in Russian) describes a risky incident in diving from a submerged submarine: the sub was neutrally buoyant, and the first frogman airlocking changed the sub's buoyancy, and the sub started to float up; after that, the sub's captain ballasted the sub well to keep the sub on the seabed while frogmen were coming out or in.
- More powerful versions of sport-diving diver-tugs.
- The Protei 5 and similar. See Diver Propulsion Vehicle.
- Some frogmen are trained to parachute in to their site of operation. The backpack box of the Russian IDA71 frogman's rebreather has two metal clips to fasten to a parachute harness.
Types of frogman operations
- Sabotage: This includes putting limpet mines on ships.
- Covert surveying: Surveying a beach before a troop landing, or other forms of unauthorized underwater surveying. The article "Riding on Proton" by Afonchenko (in Russian) may describe in passing a Soviet Bloc frogman infiltration into South Korean sea.
- Amphibious assault: Covertly reaching a site and attacking it either as a raid or an advance party to hold a position for later troops.
- Stealthy infiltration.
- Covert underwater work: recovering underwater objects. Covertly fitting monitoring devices on underwater communication cables in enemy waters.
- Investigating unidentified divers, or a sonar echo that may be unidentified divers. Diving sea-police work may be included here. See anti-frogman techniques.
- Checking ships, boats, structures, and harbors for limpet mines and other sabotage, and also ordinary routine maintenance. If the inspection divers during this find attacking frogmen who are laying the mines, this category may merge into the previous category.
- Underwater mine clearance and bomb disposal.
Derivative word usages
- Some scuba diving clubs have an entry class called "Tadpoles" for younger children who want to start scuba diving.
- British Navy men have a slang term "pond life" to mean civilian sport divers.
Errors about frogmen
Wrong use of the word "frogman"
A new English translation of the book "Twenty Thousand Leagues Under the Sea" uses the word "frogman" uniformly and wrongly to mean a diver in standard diving dress or similar (for French scaphandrier).
Supposed ancient scuba divers/frogmen
Ancient Assyrian stone carvings show images which some have supposed to be frogmen with crude breathing sets. However, the so-called breathing set was merely a goatskin float used to cross a river, and the "breathing tube" was to inflate it by mouth.
Mistakes in fiction: open-circuit scuba used by combat divers
Many comics have depicted combat frogmen and other covert divers using two-cylinder twin-hose open-circuit aqualungs, even anachronistically in stories set during WWII when in reality aqualungs were unknown outside Cousteau and his close associates in Toulon in south France. All real covert frogmen use rebreathers. The movie The Frogmen made this mistake too, but with three-cylindered aqualungs.
Mistakes in fiction: wrong depictions of open-circuit scuba
There have been thousands of drawings (mostly in comics, some elsewhere) of combat frogmen and other scuba divers with two-cylinder twin-hose aqualungs shown wrongly with one wide breathing tube coming straight out of each cylinder top with no regulator, far more than of twin-hose aqualungs drawn correctly with a regulator. See this image for the correct layout.
Movies and fiction
Frogman-type operations have featured in many comics, books and movies. Some try to reconstruct real events; others are completely fictional. Some make the mistakes described above. See also:
- Human torpedoes in movies and fiction.
- Movies about U.S. Navy SEALs.
- The movie "The Frogmen" (Twentieth Century Fox, 1951) shows some USA frogman operations against the Japanese in WWII, but shows them using wrong equipment (open-circuit aqualungs).
Nations with military diving groups
Italy started WWII with a commando frogman force already trained.
Britain, Germany, the USA, and the USSR started commando frogman forces during WWII.
Argentina
The Buzos Tácticos is Argentina's combat frogmen force.
Australia
The Clearance Diving Team (RAN) is Australia's combat frogman and underwater work force.
Brazil
See Brazilian commando frogmen.
Britain
See British commando frogmen.
See also Royal Engineers Specialist - Diver, Naval Clearance Divers and Clearance Diver.
Denmark
Eritrea
During Eritrea's war of independence against Ethiopia, the rebel forces had a combat frogman force. After the war, some of those frogman were retrained as dive guides for the sport scuba diving tourism trade.
France
Germany
India
The MCU is the elite naval special operations unit of the Indian Navy that undertakes underwater combat. See MARCOS.
Indonesia
The TNI-AL/Indonesian Navy Underwater Combat Unit is called Kopaska.
Israel
It is reported that Israel's combat frogmen are among the most effective compared to their numbers and are said to have been in many operations. They started in 1948. See Shayetet 13.
Italy
Malaysia
Malaysia has a special-forces naval unit called Paskal. It includes frogmen.
Mexico
See Fuerzas Especiales.
Netherlands
The Netherlands's Amphibious Reconnaissance Platoon is part of the Special Forces unit of the Royal Netherlands Marine Corps.
Norway
Norway's commando frogmen corps is called Froskemanskorpset.
Philippines
For the Philippines' military frogman corps, see Special Action Force.
Russia
United States
See United States Navy SEALs or its WW2 and Vietnam era precursor the Underwater Demolition Team