Iranian Fateh Class Submarines

[Jemiba]

Iran has started building a new class of submarines:

http://www.janes.com/article/30845/iran-launches-new-submarine-class

http://globalmilitaryreview.blogspot.de/2011/12/iranian-fateh-class-diesel-electric.html

On a photo ofone of it during the launch ceremony, I noticed the small propeller on the tail, just
in front of the main prop. Is it a kind of silent propulsion ?
(photo from the global military link)

 

[Orionblamblam]

The previous Ghadir class midget sub had the same thing, variously described as a secondary propulsion system or an "outboard motor." I would guess that it's meant for quietly motoring about near the enemy, and it on the top because it might have to operate in shallow water.

 

[Eagle2009]

ALCON,


That image is NOT the Fateh-class submarine...that is just a Ghadir-class submarine. It is a stock image used in the article. The only public image of the Fateh-class submarine is a satellite image published by Jane's showing one moored at the Bostanu shipyard/port (West of Bandar Abbas).


Official Iranian statements put the Fateh-class submarines in the ~500 ton displacement range and the dimensions estimated by Jane's put the vessel in the same size class as the German Type 206 and Israeli Gal-class.


Here are some images of the Fateh-class concept (physical model and CGI):

 

[Jemiba]

Many thanks for putting me right, Eagle !
Should have noticed, as the length given on the Janes site, would turn those
crew members into giants. Well, it's just too easy to take such photos for granted ! :-\

 

[kaiserbill]

ALCON,


That image is NOT the Fateh-class submarine...that is just a Ghadir-class submarine. It is a stock image used in the article. The only public image of the Fateh-class submarine is a satellite image published by Jane's showing one moored at the Bostanu shipyard/port (West of Bandar Abbas).


Official Iranian statements put the Fateh-class submarines in the ~500 ton displacement range and the dimensions estimated by Jane's put the vessel in the same size class as the German Type 206 and Israeli Gal-class.


Here are some images of the Fateh-class concept (physical model and CGI):

Very interesting.

And way more practical.

I've always been of the opinion that a submarine the size of the Type 206 would be exceedingly useful in the Persian Gulf and Gulf of Oman.

The Persian Gulf for example has a maximum depth of only 90 meters.

 

[lowlow]

Another picture of a Fateh's model.

 

[lowlow]

Iranian navy launched the 1st Fateh class submarine

http://www.scoop.it/t/newsletter-navale

 

[covert_shores]

Slowly more images and materials are creeping out. Am able to estimate the main hull diameter as 4m vs the 6m initially reported. More info http://www.hisutton.com/Fateh-Class_Submarine.html

 

[carvalho2008]

mini-submarines are still very dangerous for any marine...

 

[covert_shores]

Well it's tricky to categorize subs of the fateh's size. Not quite a midget, but hardly 'full size' either. Not sure if it's the best of both worlds or the worst of both.

Strategically, it does increase the potential for the Iranian navy to patrol the western side of the Persian gulf, at least for longer than is currently possible with the ghadir.

But this sub is I suspect operated by the navy not the IRGCN so it is likely intended for use in the Arabian Sea, where it is much less suited.

 

[stealthflanker]

Any latest information yet on surfaced displacement ? Im only got some old news here and dear wikipedia. which list 527 metric ton.

http://news.usni.org/2013/11/27/iran-launches-new-submarine-class

527metric ton, the battery may took around 20-25% of the displacement. Assuming 25% of battery it would be 131.75 metric ton.

Knowing the length and hull diameter, a reasonable calculations can be made to estimate underwater endurance. Based on Ulrich Gabler's submarine design book and Tom Stefanick's book, it yielded result of 5 days underwater endurance with speed of 3.5 knot. maximum underwater speed (in wiki) of 14 knot however can only be sustained for 14 hours.

 

[covert_shores]

Good stuff, all very reasonable.

 

[Eagle2009]

ALCON,

Here is the MashreghNews story that first quote those displacement figures (fraid it's in Farsi but even the generally useless Google Translate helps sort out the numbers).

http://www.mashreghnews.ir/fa/news/239492/%D8%B2%DB%8C%D8%B1-%D8%AF%D8%B1%DB%8C%D8%A7%DB%8C%DB%8C-%D8%A7%DB%8C%D8%B1%D8%A7%D9%86%DB%8C-%D9%81%D8%A7%D8%AA%D8%AD-%D8%AF%D8%B1-%D8%A2%D8%B3%D8%AA%D8%A7%D9%86%D9%87-%D8%B1%D9%88%D9%86%D9%85%D8%A7%DB%8C%DB%8C

This was posted in August 2013 on the IMF, here are the figures from it:

Surfaced Displacement- 527 tons
Submerged Displacement- 593 tons
Operational Depth- 200-250 meters
Endurance- 35 days (hard to tell if they mean when surfaced or submerged, tho the former seems likely)

I'll sift through the old threads in the IMF and see if I can find any other news sources...

 

[covert_shores]

Seems about right.

The single hull construction shows that it is influenced by the Nahang lineage and local construction of the IS-120 more so than overhauling the KILOs.

I wonder if this will put to sea more frequently than the KILOs? They are very rarely at sea for more than a day or two I suspect which must limit crew proficiency.

There are signs that the Iranian built subs have suffered quality issues which may have resulted in leaks. But this boat is too large to be tested in the high pressure chamber used for the IS-120s. Hope it doesn't disappear from the spotlight like the Nahang did.

 

[covert_shores]

Eagle2009, has there been any news of the Nahang in recent years?

Seems likely it's long since retired, or worse.

 

[stealthflanker]

ALCON,

Here is the MashreghNews story that first quote those displacement figures (fraid it's in Farsi but even the generally useless Google Translate helps sort out the numbers).

http://www.mashreghnews.ir/fa/news/239492/%D8%B2%DB%8C%D8%B1-%D8%AF%D8%B1%DB%8C%D8%A7%DB%8C%DB%8C-%D8%A7%DB%8C%D8%B1%D8%A7%D9%86%DB%8C-%D9%81%D8%A7%D8%AA%D8%AD-%D8%AF%D8%B1-%D8%A2%D8%B3%D8%AA%D8%A7%D9%86%D9%87-%D8%B1%D9%88%D9%86%D9%85%D8%A7%DB%8C%DB%8C

This was posted in August 2013 on the IMF, here are the figures from it:

Surfaced Displacement- 527 tons
Submerged Displacement- 593 tons
Operational Depth- 200-250 meters
Endurance- 35 days (hard to tell if they mean when surfaced or submerged, tho the former seems likely)

I'll sift through the old threads in the IMF and see if I can find any other news sources...

Excellent find. Now i believe the number in wiki is likely based on the news.

Regarding the endurance though, 35 days submerged are reasonable with snorkeling period. The sub only need to raise its snorkel to start its diesel generator which will charge battery. after charging is done it can go fully submerged again for 4-5 days depending on its patrol speed.

 

[covert_shores]

4 or 5 days might be a bit long for this sub?

 

[stealthflanker]

4 or 5 days might be a bit long for this sub?

well see my previous post.. that's quite achievable with underwater speed of only 3.1 knot.

 

[covert_shores]

I haven't read those books but I did receive some good info as part of my Sinpo Class analysis (http://www.hisutton.com/N%20Korean%20ballistic%20missile%20sub%20capability.html and http://www.hisutton.com/Analysis%20-%20Sinpo%20Class%20Ballistic%20Missile%20Sub.html). My suspicion is that the 1/4 weight of batteries rule does not scale down to a 500 ton boat as items like torpedo tubes, engines, motors etc don't scale as such.

The armament fraction on this boat (4 x TTs, 8 torpedoes as reasonable load, fire control etc) is about 32 tons.


Also these boats are operating in very high temperatures which will shorten battery life (?). See this quote from http://batteryuniversity.com/learn/article/discharging_at_high_and_low_temperatures
"All batteries achieve optimum service life if used at 20°C (68°F) or slightly below. If, for example, a battery operates at 30°C (86°F) instead of a more moderate lower room temperature, the cycle life is reduced by 20 percent. At 40°C (104°F), the loss jumps to a whopping 40 percent, and if charged and discharged at 45°C (113°F), the cycle life is only half of what can be expected if used at 20°C (68°F). " .
Temperatures in subs in the Persian Gulf get very hot. Maybe they need 131 tons of batteries just for the aircon?

 

[Grey Havoc]

Unless a semi-submersible torpedo boat (or possibly some sort of Q-Ship) was used, it's likely that one of Iran's subs is on the rampage.

 

[Moose]

Most actual analysis I've seen says limpets rather than torpedo attacks. The divers could well be working from a sub, but they could also be operating off any of several other types of vessel.

 

[GTX]

It may very well not be Iran either. What does Iran stand to gain by this?

 

[TomS]

Indeed. It seems like the sort of op that any regional power (or even well-equipped non-state actor) opposed to Iran might pull to trigger a US response.

 

[Foo Fighter]

What does Iran get from sponsoring all kinds of mayhem in other countries? It would not be the first time they got up to this sort of conduct. Of the others, North Korea would be the next most likely.

 

[Grey Havoc]

Most actual analysis I've seen says limpets rather than torpedo attacks. The divers could well be working from a sub, but they could also be operating off any of several other types of vessel.

Looks like one of the tankers in the latest attack was indeed attacked with limpet mines:

Gulf of Oman tanker attacks: US says video shows Iran removing mine

Iran strongly denies a US allegation that it was behind attacks on tankers in the Gulf of Oman.

www.bbc.com

 

[TomS]

So the video is very interesting. The vessel does seem to be a known IRGCN patrol boat type. Why they'd go retrieve a non-functioned limpet mine is a bit of a mystery, but I guess they might want to avoid leaving an exploitable device behind.

My hunch would be that this might be an op not directed by senior Iranian leadership. IRGC isn't always well controlled from the top.

 

[Moose]

My hunch would be that this might be an op not directed by senior Iranian leadership. IRGC isn't always well controlled from the top.

Somewhat feels this way to me, specifically that IRGC and those they prefer to have in control were miffed about the optics of the Ayatollah meeting with Abe peacefully and wanted to make trouble to disrupt things.

 

[covert_shores]

Crazy to think it's been 4 years since I first sketched this sub. Now here's the obligatory cutaway, based on various Iranian TV footage of the interior plus measured analysis of the outside and various photographs. Some basic accommodation elements, like galley, toilet yet to be positively located. Best guess is port side of torpedo room towards amidships.

 

[totoro]

So, the torpedo loadout is 4 per sub? One in each of the four tubes, without any reloads?

 

[TomS]

So, the torpedo loadout is 4 per sub? One in each of the four tubes, without any reloads?

Officially announced load is 4 torpedoes, 2 reserve torpedoes (reloads) and 8 sea mines. If that is accurate, and the sea mines replace torpedoes 2:1 (which is fairly typical), there is a potential for 6 total reloads. That seems about right for the reported size.

Iran most advanced domestically-built submarine joins fleet

Bandar Abbas, Feb 17, IRNA - Iran’s new domestically-developed submarine Fateh joined the country's naval fleet.

en.irna.ir

 

[totoro]

Where would that space for the 6 additional torpedoes be on the cutaway image above?

 

[TomS]

Where would that space for the 6 additional torpedoes be on the cutaway image above?

Basically, the same space marked for crew bunks (36). They'll be sleeping on racks on top of or between the torpedoes.