With thanks to Abraham Gubler & Observer114 for reminding me of this book and the trilogy it formed a part of.
John Wingate, Submarine, 1982
United Kingdom
HMS Orcus
Oberon Class Submarine
Details as per the real ships
Note: Author describes the submarine as being "...one of the last of the Oberons and in peacetime would have been consigned to the scrap-yard long ago..." This would imply she commissioned sometime in the 1965 to 1967 time period. The Oberon Class Submarines built for the Royal Navy commissioned between 1960 & 1967, with construction of the Oberons for Australia starting in the latter year.
HMS Safari
Swiftsure Class Submarine
Details as per the real ships
United States
USS Constitution (CV-??)
Kitty Hawk Class Carrier
Details as per the real ships.
Note: Author initially mentions the USS Constellation (CV-64) at one point and then uses USS Constitution thereafter for the rest of the novel for what is clearly the same ship, it is not clear if this is a misprint on the part of the publisher or not. The name clashes with one of the original ships of the US Navy, the sailing frigate USS Constitution which is nominally still in service.
Avalon 3
Mystic Class DSRV
Details as per the real ships
Avalon 4
Mystic Class DSRV
Details as per the real ships.
Russia
Various Unnamed warships
Plot summary: It is the 'Day After Tomorrow'. A conventional WWIII has been raging for some months, the attempts by the Soviets to interdict the trans-Atlantic supply lines have failed. Now, under the threat of taking the conflict to the nuclear stage they are demanding a truce. The Western Powers realize their only chance is to prove that they can take out the Soviet SSBNs before they can launch. Two British submarines are sent north with orders to sink a Soviet Typhoon Class Submarine at all costs.
Note: Author John Wingate is (was?) a British writer of nautical fiction whose career began in the late 1950s with the publication of the 'Boys own Adventure' - style series 'Submariner Sinclair' (I've covered the second volume of the series 'Jimmy-The-One: A Submariner Sinclair Story' (1960), which along with his later 'The Sea Above Them' (1975) in this thread.). This book is the last in a three part WWIII series (The other two books are 'Frigate' (1981?) & 'Carrier' (1981?)). I get the feeling the final paperback volume was hurried into publication to capitalize on the Falklands War (April - May 1982), with the use of a stock photograph rather than artwork on the cover being an unusual feature for the time, at least in fiction. The hardback edition of the novel seems to have been released shortly before the conflict started.