SSK

Submarine designation - part of the letter abbreviation designation from warships , SSK's are also refered to as conventional submarines to differentiate them from nuclear powered boats.

Diesel submarines operate but using battery power when submerged and diesels to charge them. Until recently diesel boats had to surface or snort when running diesels to get air into the boat for combustion. This made them more vulnerable to detection. However, recent advances in air independent propulsion AIP have enabled diesel boats top remain submerged during charging.

The RN does not operate SSK, having sold the last 4 to the Canadians.