Queen Camilla appeared in high spirits as she arrived at HMNB Devonport in Plymouth on Wednesday, July 16.
The 77-year-old delivered crucial speech as she commemorated the end of HMS Astute's historic first commission, the longest in Royal Navy submarine history at 15 years.
The Queen, who has served as the submarine's Lady Sponsor since naming the vessel in 2007, spoke of the "steep learning curve" ahead when the vessel returns to service.
She addressed to the Ship's Company and their families, reflecting on her 18-year role as Lady Sponsor.
The Queen said: "18 years ago, I was enormously proud to visit Barrow-in-Furness as your newly appointed Lady Sponsor. 11 careful owners, 307 million nautical miles, and 357 harbour entries later, it is such a pleasure to bring together the entire Ship's Company to celebrate HMS Astute's first commission."
She also praised the submarine's technological achievements, noting how "her warfare trials on the Eastern Seaboard of the US were so successful, proving virtually impossible to detect, that the US Navy had to update their own exercises to match her."
The royal acknowledged the crew's exceptional service, adding: "It is this inquisitive spirit and razor-sharp professionalism that has steered you all through dangerous waters and, thanks to your efforts, ensured the safety of this nation and our allies."
She continued: "I suspect that the novelty of having one’s own bunk was enough to make her ‘first of class, and second to none'"
Camilla also explained the feelings of the crew in her own words, saying: "There is no doubt that our Navy will miss her as she undergoes her refit for her next commission, and we may all find ourselves again at the start of another steep learning curve as software updates, novel technology, and enhanced weaponry transform the submarine you know so well."
The Queen went on: "That aside, and with global tectonics shifting unpredictably, she may emerge for her second commission into an unfamiliar world – a challenge that I know will be taken on with her usual tenacity."
She paid emotional tribute to the families: "I am sure that there are mixed emotions for you all today; as this close family disperses and another, in several years, takes shape as she is again ready to set sail."
The royal concluded her address with the traditional naval order: "Splice the Mainbrace."
