SLOT buoy
A SLOT buoy (English: "Submarine-Launched One-Way Transmitter Buoy" or "Submarine-Launched One-Way Tactical Buoy", German: "U-Boot started one-way transmission buoy" or also "U-Boot started tactical One-way buoy) is a buoy with radio wave transmitter for communication from submerged submarines .
purpose
The basic purpose of the SLOT buoy is to open up a communication path from individual, submerged, mostly military submarines to their higher-ranking military or civil organizations. Due to the design and use of the buoy, this communication channel can only be used from the submarine to the organization, but not in the opposite direction.
description
The buoy is about the size of a baseball and can be launched from launchers that are 3 "and 4" in diameter. For example, the following parameters apply to the buoy "SLOT 281" from the manufacturer "ALSEAMAR":
| size | value |
|---|---|
| designation | SLOT 281 |
| Max. Depth at start | 150 m |
| Max. Boat speed at takeoff | 15 kn (28 km / h ) |
| ERP | 1 W FM |
| channel | 999 UHF channels , at 25 kHz intervals |
| Message length | up to 120 s sound recording |
| Time delay (of the broadcast) | 0 minutes - 99 hours |
| Message repetition interval and number | selectable |
| Closing action | Self-immersion after the number of message retries has expired |
| storage time | up to 5 years |
The cost of a SLOT buoy AN / BRT-1 from the manufacturer Sippican Ocean Systems (part of Lockheed Martin Maritime Systems and Sensors since 2004 ) was, for example, USD 572 each in 1982 , which corresponds to around USD 1500 in 2018. Another supplier for SLOT buoys was Motorola .
commitment
Military
One of the main tactical objectives when using military submarines is to operate undetected in order to make the destruction of the submarine by enemy forces more difficult and to be able to complete missions successfully. The position of the submarine must remain hidden from the enemy, which is why u. a. surfacing of the boat, in particular in the vicinity of the enemy, is avoided as far as possible, since it can easily be recognized here visually by anti-submarine ships , anti-submarine aircraft and satellites . If the submarine also sends out radio waves for communication, it would be relatively easy for the enemy to determine the position of the boat. On the other hand, in order to be able to react to changes in position during the operation of the submarine, communication between the submarine and higher-level bodies, which are usually geographically far away on land, is of great advantage or even essential. On land there are large antenna systems with which messages can also be transmitted to submerged submarines, which the submarine cannot answer in the same way. The submarine could appear for an answer or a real two-way communication, which, however, as already described, would be tactically disadvantageous. A SLOT buoy can now be used here. The submarine saves an (encrypted) message in the buoy, ejects the buoy in a submerged state, the buoy drifts to the surface of the water and continues to drift inactive there for the time being while the submerged submarine moves away from the position of the buoy. After a previously set time has elapsed, for example 1 hour, the buoy now begins to send out the stored message by means of radio waves, whereupon it is transmitted by communication satellites and the like. Ä. can be received and forwarded to finally reach their addressee. After a pre-set period of time, the SLOT buoy sinks itself in order to withhold further information from the opponent. While it is inactive, the buoy is extremely difficult to detect by the enemy due to its small size and the partially submerged state, while its position can be determined extremely easily as soon as it begins to transmit. By the time the buoy begins to transmit, the submarine has already moved away from the position of the buoy, which is why the position of the submarine is only very limited by the buoy's transmission activity, e.g. B. can be determined within a radius of 50 km around the position of the buoy. Such a rough position determination is only of very limited use for the opponent of the submarine, whereby the risk for the submarine is correspondingly reduced. When using the SLOT buoy and choosing the length of the transmission delay of the buoy, the commander of the submarine must always weigh up the urgency of the transmitted information and the risk to the submarine.
Since the buoy attracts the attention of the enemy through its transmission activity, it can also be used as a decoy, as it attracts anti-submarine forces and binds them for a limited period of time, which can result in gaps in the opponent's line-up elsewhere, by friendly forces can be used.
In case of emergency
A civil as well as military use of the SLOT buoy is as an emergency call. Should a submarine get into a position underwater in which it needs help and cannot emerge, such as B. in case of problems with the ballast tanks, it can store an emergency call in the buoy and eject the buoy, whereupon it drifts to the surface of the water and starts transmitting the message without delay. In addition to the content of the message, the position of the buoy, which can be easily determined by other forces and which is almost directly above the position of the submarine, is of great help in the rescue operation for the submarine.
Trivia
- The SLOT buoy is z. B. Part of communications equipment on Los Angeles-class submarines
swell
- Tactics 101: Anti-Submarine Warfare (ASW) - Part 2 , 2009
- Douglas Savage: Incident in Mona Passage: A Novel , Taylor Trade Publishing, 2014, ISBN 978-1-58979-848-9
- Michael DiMercurio: Phoenix Sub Zero , Crossroad Press, 2017, ISBN 978-1-55611-392-5
- Michael DiMercurio: Threat Vector , Crossroad Press, 2017, ISBN 978-0-451-40908-9
- Michael DiMercurio: Barracuda Final Bearing , Crossroad Press, 2017, ISBN 978-1-55611-458-8
- Tom Clancy, John Gresham: Submarine: A Guided Tour Inside a Nuclear Warship , Penguin, 2003, ISBN 978-1-101-00258-2
Individual evidence
- ↑ SLOT Abbreviation , AcronymFinder
- ↑ CHGates: Anti Submarine Warfare (ASW) Lexicon , Naval Ocean Systems Center, San Diego, 1990, p 29
- ↑ Data sheet for SLOT 281 from ALSEAMAR
- ↑ The Sippican Corporation , Science Museum
- ^ Mike H. Rindskopf: Steel Boats, Iron Men: History of the US Submarine Force , Turner Publishing Company, 1994, p. 72
- ↑ John Steel: Sippican's ocean-going swimmingly snooper devices , NewsOK: Oklahoma City News, 1982
- ↑ CPI Inflation Calculator
- ^ Motorola 1972 Annual Report - Motorola Solutions
- ↑ ATP-57 (B) The Submarine Search And Rescue Manual , NATO, 2009, pp. 37, 46, 54, 200, 204, 572