Crucial to the success of the defence was the support from the Tobruk Ferry Service from the RN Fleet Base at Alexandria. This included Australian destroyers.
In the face of threats from air, surface and submarine attack, eight RAN destroyers made almost 140 voyages to Tobruk, providing gunfire support, escorting and delivering stores, food and ammunition and evacuating the wounded. HMAS Vendetta made over 30 individual supply runs.
Both HMAS Waterhen and HMAS Parramatta were sunk while on these hazardous duties, the latter with heavy loss of life.