SEALOL is the brand name for a group of industrial seals used on both RN and US submarines. Originally patented and manufactured for years by EG&G in Warwick, RI, the company sold the business to the John Crane company.
Seals of every type are used in many areas aboard submarines, from compressors to water seals, hydraulics, etc. There are few systems aboard a submarine that don't require some type of seal.
The original Patent description for the SEALOL seal is linked below.