During WW2, Fremantle Harbour in Western Australia became the largest submarine base in the southern hemisphere. 170 submarines of the British, Dutch and American navies used ‘Freo’ harbour as their base making 416 war patrols out of Fremantle.
Across the harbour entrance was an anti-submarine ‘boom’ net which was lowered when friendly shipping entered the harbour and kept raised at other times. The Fremantle boom defence net was a buoyed wire mesh net with a central gate opened by a winch on the North Mole, and two buildings were constructed on the western end of Victoria Quay for the naval boom defence operating unit.
The remnants of the lowering/raising machinery are still to be seen on both sides of the harbour entrance. Click images to enlarge them
Harbour entrance
Winding machinery...Sth Mole
Winding machinery...Nth Mole
U.S. subs with mother Ship
HMS Adamant and Brit subs
Wartime photos taken by Saxon Fogarty