HMY Britannica was the royal yacht before being retired in 1997. It was scheduled to be built just as World War II took off so the plans were delayed. Queen Elizabeth’s father began working on it after WW2 but then unfortunately died… so the Queen took control of the plans. It was used for many state visits and sailed an equivalent number of miles to sail around the world every year it was in service. Young royals used it for their honeymoons as well, including Charles and Diana. It provided privacy, even with a staff of 300!
The Queen and King each had separate bedrooms but they adjoined. Charles had a double bed put in for his honeymoon and it was the only one on the boat. The walkway below the Queen and King’s windows was lower so that people were less likely to accidentally look in while passing by.
All chores, including washing the large private deck had to be completed by 8am and the crew was not allowed to wear their hats in this areas so that the crew would not have to formally salute whenever they saw a royal. The crew was to remain perfect still and quiet until the royal passed. Working in silence led ot the use of a lot of hand signals.
On the tour, stuffed corgis were stahed in rooms, including one bandaged up in the medical area.
The boat is now used for various functions on occasion by the royals, including for Zara Phillips’ pre-wedding event.
I apologize as I didn’t take any photos. You can view the official website here though.