Slowly, more information is creeping out concerning Iran’s new attack submarine, the Fateh. The Fateh is the latest in a series of indigenous submarine projects and is by far the most potent to date. With imagery analysis, we are now able to see beneath the skin.
Fateh Class SSN - image added 3rd May 2017
The new class of submarine is significant for several reasons. Firstly she is much larger than previous Iranian made boats and can carry at least four torpedoes. Her length is estimated to be 48m and her beam about 4m, giving her a displacement in the region of 300 tons.
Secondly she appears to be a truly indigenous design (there is a suggestion that it might be a Chinese design but that is unproven). The main Iranian built submarine type to date has been the IS-120 'Ghadir' Class, which is really the North Korean designed MS-29 'Yoneo'. The Yoneo is a potent and proven midget submarine armed with two 533mm (21 inch) torpedoes, but she is much smaller and consequently has limited endurance. In fact the Yoneo is about half the length and a quarter of the displacement of the Fateh. Earlier truly indigenous submarine designs appear to have all been experimental or at best only limited successes not put into series production (e.g.Nahang Class). Whether the Fateh is also a one-off design has yet to be seen, but outwardly she gives the impression of being a tactically useful unit. Her size also gives her the possibility to carry weapons with more significant negative buoyancy, for example the 'Hoot' supercavitating rocket-torpedo (a weapon much publicised but yet to be evidenced in service)
Ghadir submarine - a much smaller imported design used by both the Iranian Navy and the Revolutionary Guard Navy (IRGCN).
The Fateh is about 48m long with a generally conventional hull form with blunt vertical bow and tapered stern. This is similar to the German Type-206 series deigns and former-Yugoslavian 821 (Heroj) and 831 (Sava) classes. It is difficult to say whether she carries any reloads for her four bow torpedo tubes, but from the distance between the bow and the sail it seems probable that she does. A useful load of about ten torpedoes or twenty mines seems a reasonable assumption.
Photo and satellite analysis suggests that the boat is about 4m in diameter (initial estimates were as much as 6m, which would be a much bigger boat). This is enough for two floors, as confirmed by the leaked plans.
Helpfully, we got a glimpse of some construction plans. There is a lot this doesn't show, and yet a lot we can deduce:
Hull cross-sections. The orange circles represent torpedo tubes. Although the Fateh has a larger diameter hull than either the Ghadir or North Korean Sang-O, it is still much smaller than even the German Cold War Type-205 ‘coastal submarine’. The more modern Type-209, which is just entering service with Egypt, is bigger again at 6.5m.
Useful information about the control room. Overall more likea scaled up Ghadir midget sub than a scaled down KILO...
The diver lock-out trunk appears similar to the Ghadir Class, and seems to be mounted forward of the Control Room, further refining our understanding of the internal arrangement
Below the torpedo tubes is space for circular sonar arrays with asmaller set mounted above them. The sensor suite of a boat this size will be relatively limited but still much more powerful than on the smaller Ghadir. The sail is set quite far back along an unusually stepped forward casing which barely rises above the top of the hull at the bow, before rising up halfway along to allow the forward hydroplanes to be mounted. The sail has a blended leading edge similar to the latest American boats. Curiously there is an external ladder up the forward part of the sail rather than a hatch, suggesting a diver lock-out is built into it like on the Ghadir.
An Iranian made circular sonar array consisting of vertical staves. This layout is similar to WW2 and 1950s Soviet designs.
Behind the sail the casing extends in a more conventional manner, with a hatch down to the engine room part way along it. This is a luxury not afforded to the crew of the Ghadir. The tail is conventional with a cruciform arrangement and a five-bladed screw-back propeller which could well be the same type as on the Ghadir. Unlike the Russian supplied KILO submarines operated by the Iranian Navy she appears to be a single-hull design. Having said that, there are a series of flood holes along her beam whose exact placement are hard to explain but will relate to the ballast tanks.