A Chinese Type 041 "Yuan Class" diesel-electric submarine. Pakistan may have sought to buy six of these if funds were available, but funds were not.
The Diplomat magazine (based in Tokyo) published an interesting article by Andrew Detsch on October 9, 2013 http://thediplomat.com/flashpoints-blog/2013/10/09/pakistans-oversized-submarine-ambitions/ concerning "Pakistan’s Oversized Submarine Ambitions"
Detsch interviewed Haris Khan, a senior analyst at PakDef Military Consortium, an independent Tampa-based think tank, with Khan making some points regarding Pakistan's envisaged naval modernisation, including:
- Pakistan's 2008 debt problems (now standing at US$58 billion) led to the shelving of Pakistan's plans to buy three HDW 214s and tentative plans to buy six diesel-electric Chinese submarines (presumably China's Kilo like Type 041 were envisaged). These would have augmented Pakistan's current submarine fleet of two Agosta-70s, three AIP equipped Agosta 90Bs and three midget MG110 "Cosmos" class subs.
- According to Khan, since 2001 the Pakistan Atomic Energy Commission (PAEC) has been working on KPC-3, a project “to design and manufacture a miniaturized nuclear power plant for a submarine.” [This is presumably a response http://rusnavy.com/nowadays/concept/opposite/arihant.htm?print=Y to India's indigenous nuclear submarine INS Arihant].
- "PAEC and the National Engineering and Scientific Commission (NESCOM) have been working on a miniaturized plutonium warhead, a naval version of the Babur land attack cruise missile, which will further enhance Pakistan’s deterrent capability."
Regarding the reference to a Pakistani KPC-3 submarine nuclear propulsion project - the cost (and opportunity cost) of such an endeavour and low strategic utility of such submarines for Pakistan are two arguments against building nuclear submarines.
Geography indicates that nuclear submarines operating from Pakistan would be highly vulnerable to air power, MRBMs and conventional submarines. Pakistan's AIP capability for its three Agosta 90 submarines is a more cost effective route to provide highly efficient anti-shipping, anti-submarine and missile land attack capabilities.
Nuclear tipped Babur land attack cruise missiles provide a logical capability enhancement.
Connect with this website's http://gentleseas.blogspot.com.au/2013/07/pakistan-submarine-capabilities.html of July 31, 2013.