The memorial consists of three main parts, a walk way with commemorative plaques, the Orion fin and the Derwent gun turret.

The fin of the Orion was placed in the Naval Memorial Park, while the port propeller was donated to the Western Australia Maritime Museum.

Markcrow and Humphreys were lost when the submarine Otama dived off the New South Wales coast on 3 August 1987; their bodies were never recovered.

The ship's sole 4.5-inch gun turret was preserved and placed at the Naval Memorial Park, facing HMAS Stirling.

[7] The installation of the turret at this location pre-dates the official opening of the Naval Memorial Park, having taken place in June 1995.