Unlike torpedos SLAMs have generally not been seen as essential equipment. Projects to develop SLAMs have risen and fallen for at least 45 years. In 1972 the UK tested a Blowpipe SLAM system on HMS Aeneas (P427) in 1972. This consisted of a cluster of four missiles on a mast that could be raised from a submarine's sail/fin. This system was then installed on an Israeli Gal class (modified UK built HDW 206) submarine.
Reasons why SLAMs have not been adopted may include difficult and slow operation making for low effectiveness and need for the submarine to expose itself to the attacking helicopters or maritime patrol aircraft (MPAs). However advances in SLAM technology may be making them a more worthwhile inclusion in a submarine.
Factors that may encourage submarine captain to use a SLAM include:
- whether it is a wartime emergency situation where the submarine has been detected, or detection is imminent, by a helicopter/MPA? Detection might be by helicopter dipping-active sonar or fixed wing maritime patrol aircraft (MPA) dropped sonobouy.
- whether the SLAM can be deployed in such a way that minimises submarine exposure?
- could increasing long range, or stealthier, SLAMs be arguments for greater use?
: float-up container or
- how quick is that mode? (the quicker the better to defeat the helicopter/MPA's actions or countermeasures).
- does the SLAM armed submarine (eg. a Kilo) have a major anti-aircraft role in support of other higher value submarines (eg. SSBNs)?
- does the missile carry added benefits/fuctions like anti-missile, anti-shipping or light land attack capabilities?
France and Germany have been marketing SLAM solutions. Russia is thought to have developed Strela-3 and Igla SLAMs and no doubt US companies have developed SLAM ideas at times. It is difficult to gauge how mature the technologies are.
A mast mounted MICA missile has also been tested but slower reaction-vulnerability shortcomings of the mast mounted concept were apparent.
It remains a point of contention whether IDAS has been actually fitted to Germany's latest Type 212 submarines. There is no mention of IDAS on latest commissioned https://de.wikipedia.org/wiki/U_35_(Bundeswehr) or on not yet commissioned https://de.wikipedia.org/wiki/U_36_(Bundeswehr) .
My view is that IDAS is still not operational on 212s. An IDAS missile was tested in the Baltic on Type 212A U33 in May 2008 and did hit a simulated air target. The IDAS consortium indicates it is conducting the Initial Development Program aiming at verification of the system with firings from a submerged submarine against real targets - see http://www.diehl.com/en/diehl-defence/products/guided-missiles/idas.html .