The repair ship Medusa was launched at Puget Sound Navy Yard on 16 April 1923. Her displacement was 8,125 tons, length 460 feet and beam 70 feet. She carried four 5-inch, 51 caliber and two 3-inch anti-aircraft guns. Her complement was 466 men. On 7 December she was moored in Middle Loch due south of Pearl City and at 0830 the destroyer-minesweeper Zane reported sighting an enemy midget submarine 200 yards astern of her. Immediately east of Medusa was Curtiss and she opened fire. Medusa joined in, and also reported seeing a torpedo fired. At 0900 three bombs dropped only 20 feet off her port quarter, but no damage was done.
You can find out more about the Medusa in the following Osprey book: