Nautilus resulted from Keyes' desire to produce an ocean going submarine with greatly improved se keeping qulities for extended operations in all conditions of weather. The design produced by Vickers was for a submarine twice the size of the standard E class overseas submarines. Keyes'expected the results of the trials to decide the future of the big submarine in the British Navy.
The specifications for Nautilus were far outside of what could be attained at the time. This situation at least prevailed with respect to the propulsive machinery, there simply existed no diesel engine with the required power. It remains a mystery to this day how it was possible to order the construction of a vessel of which it was known that the production of the required power plant was simply out of the question.
Nautilus was attached to 6th Flotilla at Portsmouth from 1917, she never became operation and remained moored in a dockyard basin serving as a battery charging vessel.
2 Electric Motor 1,000hp.
Twin Screws (3 bladed)
10 kts sm
1 x 3 inch AA gun.
72 nm max.