HMS Torbay is a decommissioned Trafalgar-class nuclear submarine of the Royal Navy and the fourth vessel of her class.On 6 June 2017, she entered Gibraltar Naval Base flying her paying-off pennant and, on Friday 14 July 2017, the vessel was decommissioned in Devonport.[citation needed] In early 2006, Torbay was the participant in an experiment in the use of colour schemes to reduce the visibility of submarines from the air.The standard black paint of Royal Navy submarines was replaced by a carefully selected shade of blue.This was the result of research that found that black was the worst possible colour for a submarine attempting to avoid detection from the air.