April 30, 2012: For the United States the most dangerous and unpredictable naval weapon Iran has is its fleet of twenty submarines. This is a relatively recent development and it's unknown how effective this force might be. The world may soon find out as Iran, under increasing economic sanctions because of its nuclear weapons program, has responded with threats of violence. The subs are a large part of that threat. The U.S. is not revealing what it knows of Iranian submarine warfare capabilities. That's normal, for if the Iranians knew what the Americans knew they could tweak their own plans to deal with likely U.S. countermeasures. Most likely (based on Cold War practices) the U.S. has been using aircraft, satellites, subs, and underwater sensors to monitor the activities of Iranian subs at sea. This would involve violating international law by quietly moving into Iranian territorial waters. But this has been done before, and the Iranians are probably aware of it (but not willing to publicize it and the fact that they have not been able to do anything to halt the American incursions). The Iranians tend to be smart when it comes to technical and military matters, and they are aware that the U.S. has over a century of experience in submarine operations. Have the Iranians come up with ways to overcome their shortages in technology and experience? No one will know unless the Iranian subs go to war.
Iranian efforts to build a submarine force began in the late 1980s, when the Islamic Republic of Iran Navy acquired a few midget subs from North Korea. These boats were capable of delivering frogmen covertly or carrying naval mines to attack shipping and harbors. Iran took the big leap in the early 1990s when they acquired three Kilo Project 877/636 type diesel electric submarines from Russia. The 2300 ton Kilos are long range subs capable of operating throughout the Indian Ocean (from South Africa to Australia). The Kilos have six 533mm (21 inch) torpedo tubes and 18 torpedoes (including one or more Shkval rocket torpedoes) or 24 mines. Very similar to the world-standard diesel submarine, the 1800-ton German Type 209, the Kilo is a formidable foe and can stay at sea for up to 45 days. The last of these three Kilos were delivered in 1996, which gives Iranian crews more than a decade of experience. Google Earth has often spotted the trio tied up in harbor at Bandar Abbas, however, they have made several training cruises to the Persian Gulf and Arabian Sea.
Russia agreed to stop selling subs to Iran in 1996, and since then Iran has been working on their own designs. After ten years of trial and error they produced the 100 ton Ghadir (Qadir) class vessels in 2005. Iran currently has 12 of these small diesel electric subs. These smaller Ghadir-class vessels are squarely between the old midget submarines and the Russian Kilos. The Iranians are not releasing specification sheets to anyone but they look very similar to the Italian made Cosmos SX-506B submarines that Columbia received in the 1980s. The 100-ton SX-506Bs are only large enough to carry commandos and mines. However, news photos show what looks like to be two torpedo tubes on the Iranian craft.
It should be remembered that Cosmos exported a number of larger vessels to Pakistan in the 1990s. Dubbed the SX-756, they may have been the design basis for these Ghadir. It should also be acknowledged that the North Korean Sang-O class submarine closely approximates the Ghadir type. In 2007, North Korea gave Iran, outright, four of its Yugo-type midget submarines. These Yugos were well worn, 90-ton, 65-foot craft but Iran accepted them all the same.
There also appear to be five larger Nahang class subs. The first one appeared six years ago. At about 500-tons it is the same size as and closely resembled the old German Type-206 class. The Type 206s were produced in the 1960s for operations in the confined shallows of the Baltic. Denmark, Norway, Germany, and now Indonesia used variants for forty years. The Type 206’s size enabled it to carry eight torpedo tubes with no reloads. The Iranian version does not seem to be a success and little has been seen of this craft.
Under construction is what will be the third indigenous Iranian design. Laid down in 2008, the Qaaem is a 1000-ton boat and should be large enough to handle a full set of torpedo tubes along with a reload. They could be the possible replacement for Iran’s Kilos. The Kilo platform has a lifespan of 30-years and they are more than halfway there. But Iran has a mixed record when it comes to warship construction, and the Qadir boats are reported to be troublesome to use and not safe. The Iranians are enthusiastic about having more subs but developing that capability is very expensive and time consuming.