As luck would have it, these 2 covers turned up on the same day from two different sources, and surprisingly the two submarines noted were related in time and place, even to the point that the two had been berthed together in Sydney Harbour, at one point in time.
The first large cover was On Her Majesty's Service, with a purple stamping and blue vignette showing it was sent by Air Mail. It was addressed to The Navy Secretary, Navy Office, Wellington, New Zealand, with a total of 8d postage made up of three QE II definitives, the blue-green 3d, the carmine-lake 4d and the deep slate-purple 1d, all issued in 1959. The stamps were cancelled with a single faint NAVAL P.O. BALMORAL/ 23 FE 60/ N.S.W- AUST postmark. There were 3 additional markings, a printed 'Code No. 26-72', a red boxed COMMANDING/ OFFICER/ 23 FEB 1960/ H.M.S. ANCHORITE and a purple double circle NAVY OFFICE/ 27 FEB 1960/ WELLINGTON, N.Z. receiving mark (Figure 1).
The second cover was equally well documented, with a purple U.S.S. HALIBUT (SSG(N) 587)/ CARE OF FLEET POST OFFICE/ SAN FRANCISCO, CALIFORNIA marking, a black UNITED STATES NAVY ATOMIC/ SUBMARINE HALIBUT SSG-N-587/ "GOOD WILL VISIT DOWN UNDER" SYDNEY, AUSTRALIA 4 MAY 1960 marking, plus a purple shield containing USS HALIBUT, a diagram of a submarine with a rocket shooting out of a flat fish, and SSGN (separated by an insignia suggestive of radioactivity) 587. The cover was unaddressed, the stamp was the U.S. 8c Liberty, which was clearly postmarked G.P.O. SYDNEY/ R.S./ 10-A-4MY60/ 1/ N.S.W-AUST (Figure 2).
The shield on the cover was a copy of the patch worn on the uniforms of the sailors, and came with and without the firing of the rocket. A cynic might question the reason for the 2 designs, perhaps concerns about demonstrations in different ports (Figure 3).
Whereas the covers were totally different in intent (the first cover official mail, and the second philatelically inspired) and there was exactly 10 weeks difference in the dates on the two covers, there is proof that they were berthed together in 1960 in Sydney Harbour, before the HMS Anchorite set off to New Zealand where it met an ignominious fate. There are many points of interest and speculation concerning these two covers.
The Royal Navy HMS Anchorite was one of ten submarines stationed in Sydney during the years 1949 to 1969. They were offered to the Royal Australian Navy for training purposes, the flotilla usually comprising 3 or 4 ships. The Anchorite was one of the "A" class (others were Aurochs and Andrew) in service during the period 1957-1960, and they were replaced by the "T" class submarines in 1960. The Balmoral Naval PO was 9k from the Central Business District of Sydney and it was opened in July 1945 and was not closed until September 1992, Balmoral being at the entrance to Middle Harbour.
Two submarines of the United States Navy have borne the name USS Halibut, and both have had an association with Australia. The first USS Halibut (SS-232) attempted unsuccessfully to intercept the Japanese submarine I-6 when it laid magnetic mines near the approaches to the Brisbane River on 13 March 1942. The US Navy at that time had a large submarine base at Capricorn Wharf at New Farm in Brisbane.
The second USS Halibut (SSGN 587) was the first American submarine to be designed to launch the guided 'Regulas' missiles. She was launched in Vallejo, CA in January 1959, and she departed on her shakedown cruise March 11, 1960. On March 25 she became the first American nuclear submarine to successfully launch a guided missile. On her voyage to Sydney she was under the command of Lt. Commander Walter Dedrick. The reason for the visit to Sydney in the first week in May was for the remembrance celebration of Coral Sea Week during WW II.
The proof that the two submarines were in Sydney Harbour at the same time is found in a picture of the two, with the following caption: "Halibut (SSGN-587), and Regulas missile in Sydney Harbor with the British Submarine HMS ANCHORITE outboard, circa early 60's" (Figure 4).
The fate of both submarines is known, the Halibut was disposed of by submarine recycling in 1986. The Anchorite was damaged on 3 October 1960, striking an uncharted rock in Hauraki Gulf off New Zealand, and was broken up in Troon, Scotland in 1970. Could the O.H.M.S. letter from the Commander of the Anchorite sent to the Navy Secretary, Navy Office Wellington New Zealand have been in relation to this impending trip, for it certainly ties in nicely?.