Boat "fire", Sydney Heads

Whilst undertaking a beach patrol, the crew of Lifesaver 1 observed what appeared to be a large plume of smoke on the surface of the water some 5 miles east of Sydney Heads at approximately 1515 hours.   Almost at the same time, police contacted the Westpac Life Saver and advised they were receiving reports of a boat on fire in that area.   Upon investigation, it was found that it was a naval submarine, venting its systems as it prepared to submerge!