She was sunk during the Second World War at Manila Bay in December 1941 and was later salvaged by the Imperial Japanese and renamed Hatsu Maru.

Her tasks included transporting iron ore to the steel works at Port Kembla and coal to South Australia for the use of the Commonwealth Railway.

[3] She ran aground on Curlew Island near the head of Spencer's Gulf on 18 February 1930,[4] once at Port Kembla, New South Wales, and at Cape Three Point, Broken Bay on 23 October 1937.

Iron Monarch was seriously damaged on the Stockton breakwater at Newcastle on 26 November 1934 requiring repairs at Cockatoo Island Dockyard, Sydney, which cost £8,985.

[7] On 13 November 1944, she was sunk after being bombed by United States Navy carrier based aircraft in Manila Bay, Philippines.