[geoschmo]

Actually an electric/diesel sub running on batteries is quieter then a nuclear sub. The main noise producer at that point is cavitation from the blades. That varies depending on the blade design, but is better for all blades at slow speeds. One of the big spy scandels at one point was when they "accquired" some of our blade design tech.

The Soviets at their height had some very good subs. Some were quieter then our best subs, but we had much better detection tech so for the most part we were still able to keep track of them. They had a different doctrine though, prefering to keep their subs close to home. For that the diesel/electric sub's shorter range isn't as much of a weakness compared to nuclear powered.