An appeal to fund urgent restoration work on Britain's last WWII submarine on public display has raised £4.6m but still needs a further £1.5m.
HMS Alliance, which is moored in Gosport, Hampshire, is corroding so badly that parts of the memorial are falling into the sea.
The money is needed to return it to how it looked when it launched in 1945.
The vessel was in service for more than 25 years and has been on display at the Royal Navy Submarine Museum since 1982.
Vice Admiral Sir Tim McClement, chairman of the Alliance appeal, said: "The outer skin of Alliance is deteriorating at such a rate that we haven't a moment to lose, so funding for the work must be found as quickly as possible."
The museum has a memorial dedicated to submariners who have died defending the UK.
The area of remembrance was opened by Prince William in 2008 and lists 5,300 personnel who have died between 1904 to the present day.
HMS Alliance is listed in the UK's historic ship's register alongside the Cutty Sark, the Mary Rose, and HMS Victory.