On the contrary, diesel subs are extremely quiet, and if you look through US Navy exercises,
they lost to diesel subs every single time over the last 30 years.
"Twenty-three years ago during the 1981 NATO exercise Ocean Venture, an
unnamed 1960s vintage Canadian diesel submarine “sank” the carrier USS America without once being itself detected, and a second unidentified vintage sub “sank” the carrier USS Forrestal.
What did we learn from this?
Eight years later, during NATO exercise Northern Star, the Dutch diesel submarine Zwaardvis stalked and “sank” the USS America
again. Did the America just have problems? Well, in RIMPAC 1996, the Chilean diesel submarine Simpson “sank” the carrier USS Independence, and in 1999 during NATO exercise JTFEX/TMDI99,
Dutch diesel submarine Walrus not only “sank” the carrier USS Theodore Roosevelt, but also “took out” the American exercise command ship USS Mount Whitney, plus a cruiser, several destroyers and frigates, and the nuke fast attack USS Boise – all without herself receiving a scratch.
Then, during RIMPAC 2000, the Australian Collins Class diesel sub HMAS Waller “sank” two American nuke fast attacks and got dangerously close to the carrier USS Abraham Lincoln. During Operation Tandem Thrust in 2001, HMAS Waller “sank” two American amphibious assault ships in waters between 200 to 350 feet deep, barely more than the length of the submarine itself, and an unnamed Chilean diesel sub “took out” nuclear fast attack sub USS Montpelier
twice during successive exercise runs. A year later in October 2002, HMAS Sheehan successfully hunted down and “killed” the U.S. fast attack USS Olympia during exercises near Hawaii, and just a year ago in September 2003, in an unnamed (read “classified”
exercise, several Collins Class subs “sank” two U.S. fast attack subs and a carrier – all unnamed, of course. And a month later another Collins Class sub surprised and “sank” an American fast attack during another exercise."
Just few years back, Chinese crashed US exercise with diesel subs, popping up in the middle of carrier group, penetrated undetected all US defenses.
Bottom line: Is anyone still surprised Iran is mass producing extremely quiet small subs? They are very good in the ocean, and even better in the shallow waters of Persian Gulf.
