You seem to be focussing on one issue pintohoo - noise, so I...

You seem to be focussing on one issue pintohoo - noise, so I will emphasise the most important ones.

Have you read or seen Das Boot, or the Cruel Sea perhaps? This might give you a little perspective when it comes to diesel electric subs, although the technology has of course moved on considerably.

The faster a diesel - electric sub travels under water, the quicker its batteries discharge, and the more frequently it must surface. Nuclear subs do not have this limiting factor. They can stay submerged for months if necessary, and at whatever speed they choose.

The range of a diesel sub is limited by the capacity of its fuel tanks - unless it can top up mid ocean. Range may also be limited by other considerations.

As you know the UK have 4 Nuclear armed Vanguard class submarines (In addition to their Attack subs) which they rely on as their nuclear deterrent.

The whole premis of these submarines is that they cannot be detected. Quite simply - a diesel - electric submarine can. That is not what Australia needs nuclear submarines for however. It is their range. The fact that they are much harder to detect makes them far less vulnerable.

The nuclear powered submarine is streets ahead in terms of capability.