As indicated on July 24, 2019 Iran's main naval base is at Bandar Abbas just inside the Strait of Hormuz. See map above. But Bandar Abbas is at a chokepoint easily blockaded by US and UK SSNs and aircraft covering the Strait of Hormuz. Iran has attempted to give its navy more room to manoeuvre by building up a dual-use civilian/naval base at Chabahar on the Gulf of Oman. But the Gulf of Oman is also a chokepoint easily blockaded.
Blockade activity is expedited by mobile passive sonars on US and UK SSNs and probably the more efficient use of sonar on USN Echo Voyager extra large UUVs. Several networks of fixed undersea sensors are also likely (in the Persian and Oman Gulfs, Strait of Hormuz, broader Indian Ocean, Arabian, Red and Mediterranean Seas). UK/US mobile and bottom rising mines, SSN and aircraft dropped ASW torpedoes would provide weapons backup for all these sensors in the sinking of Iranian submarines.
Israel and the Sunni Arab nations (especially Saudi Arabia and UAE) astride the Persian Gulf may also be prepared to make ASW contributions against Iran.
All this means that however numerous Iran's broad selection of submarines (3 Kilos and about 17 to 31 medium-small-minis) the life expectancy of Iranian submarines in a medium level war in and around the Persian Gulf might be 2 hours at most.
Another factor weighing against Iranian submarine survival is the narrow and shallow seabed of the Persian Gulf (average depth 50m with a few small holes down to a mere 90m (see right sidebar and also depth map below. Additionally narrow-shallow channelisation of the Strail of Hormuz would make the movement of all but the smallest Iranian submarines highly predictable/detectable.
Still, the sinking of a South Korean corvette Cheonan in 2010 by a North Korean sub perhaps as small as 130 tons suggests that even Iran's mini-subs might prove dangerous if they fired a torpedo or two at warships or tankers.
Still, the sinking of a South Korean corvette Cheonan in 2010 by a North Korean sub perhaps as small as 130 tons suggests that even Iran's mini-subs might prove dangerous if they fired a torpedo or two at warships or tankers.
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This interesting English narrative (from 38 seconds in Youtube) displays all 3 of Iran's 26 year old
Kilo class medium size subs and 3 of Iran's 14 to 23 small-mini Ghadir class (120 ton, 2 torpedo) submarines.
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The narrow, shallow, waters of the Persian Gulf area make life especially dangerous for Iranian submariners. Although the Persian Gulf's oceanography would probably keep the US and UK's much larger 7,000+ ton SSNs well away in the Arabian Sea.
Pete
Pete