Defence procurement bungles and wins

[Baggers]

Thanks DJ. For context, from a weaponry point of view, how much does sub carry? I know nuclear subs can stay submerged for months at a time and can be virtually undetectable, but what sort of weapons payload can they carry compared to say a surface battleship?

David's answer and the Spotted One's were really thorough, GTC, and spot on.

Comparing subs to surface ships is can be misleading as their roles are quite different.

Surface ships are far more vulnerable to air attack. Subs are more a strategic stealth vessel - they can arrive near (within kms or 100s of kms) a target undetected, launch their payload, then FO. They are also used as support for surface ships, patrolling waters hundreds of kms around said vessels, undetected.

Surface vessels and aircraft can be detected with modern equipment from a considerable distance... subs, not so much. Used effectively subs can be on your doorstep before you realise.