Pardon my basic Question : Why is a nuclear submarine considered the most survivable of a nuclear triad in our situation ... ?
As opposed to say the offroading missile erector launcher vehicle or as in India's case rail mobile containerized/camoflaged ballistic missile ?
5 -10 missiles together in a boat is quite risky compared to a situation where each of the 5-10 missiles is scattered in a very wide area on offroading TELs which once identified to track require equal no of surveilance SATs in an ideal case which will be expensive proposition for the enemy.
If we project to have 4-5 subs wouldn't it be the case that all off them will be continuosly marked and tailed by enemy nuclear ssns or asw assets and are vulnerable to a preemptive attack just as land based fixed silos .. Its not that we have arctic ice near to seaports where a sub a can lurk away from the threat of aerial asw assets or subs that can outrun or dive deeper than enemy ssns.
Even in case we confine the subs to the littoral/coastal zone within our EEZ (as china used to do) its probable that they will be continuously marked by enemy ssns lurking near the boundary zone and sensors on subs or unmanned deepsea ones are getting more and more sensitive these days (able to track over 100's of miles) and in a preemptive nuclear strike situation enemy subs can immediately direct a fast airborne asw to the quadrant the sub is currently lurking.
If above is the case isn't it better to invest in SSNs than SSBN s until the quantitative and qualitative disparity with the enemy comes down to manageable levels ?
In the above scenario consider enemy Ssn and asw to be Los Angeles class and ACTUV
http://en.m.wikipedia.org/wiki/ACTUV and the Aerial ones to be the various conventional airborne platforms that massa employs.