Wow I already have pages of notes. Every day something new.
July 4th- ".. then out to N.O.B. where they were were opening their new club and welcoming Adm. Berry who got in on the Polaris two days ago. We were hoping he'd get rid of Capt. Alexanderson and straighten this place out".
NOB- Naval Operations Base (Iceland).
Admiral Donald Beary was Commandant of Naval Operations Base Iceland beginning in June 1942. He was a major figure in the development of Unrep (underway replentishment) which this diary is concerned with, although Rapidan seems to have been more of a floating gas station.
USS Polaris AF-11 was a C2 freighter that made trips between Iceland and the US from June 1942 to February 1943.
Captain Leroy Alexanderson was a senior officer of the USS Melville AD-2, a destroyer tender that at the time was based in Hvalfjorjour, Iceland and tended convoy escorts in the Atlantic. It's not clear to me whether he was still on the ship, had some role in NOB Command, or other positions. He ended his career as Commodore of the United States Line and was last Captain of the SS United States.
Most all of this is just Wiki grabs unless noted otherwise.
The author was most definitely in Iceland when the diary was written, probably in Reykjavik.