Rosyth for Singapore on a sustained high speed run. The round trip finished as 4640 miles surfaced and 26 545 miles submerged.
Apart from minor hull-cracking problems, Dreadnought proved to be a reliable vessel, popular with her crews. In 1970, she completed a major refit at Rosyth in the course of which her nuclear core was refuelled and her ballast tank valves were changed to reduce noise. She re-commissioned on 10th September, 1970 - and had a commemorative postal cover to prove it. On 3rd March, 1971, she became the first British submarine to surface at the North Pole.
Placed on the disposals list in 1983, having exceeded her designed 15 year hull life by a further 8 years, Dreadnought was
