Her diameter was at least twice that of any conventional submarine.

No conventional submarine I'd ever been on could have operated at this depth.

In the first place, a conventional submarine wouldn't be under the ice anyway.

Both speed and underwater endurance was at this time very high for a conventional submarine.

Though far less capable regarding speed and weapons payload, conventional submarines are also cheaper to build.

A conventional, or non-nuclear, submarine could stop dead in the water, running entirely on her battery power, and be completely silent.

The main difference between conventional submarines and nuclear submarines is the power generation system.

Her length was at least twice that of the conventional nuclear submarine.

Such devices are deployed from a service ship or a specially outfitted conventional submarine.

The propulsion system of Osprey class submersible is the most significant features that differentiate it from other conventional submarines.