In 1943 Qantas, the British Air Ministry and BOAC (formerly Imperial Airways) agreed to a daring plan to re-establish the Australia-England air link that had been cut by advancing Japanese forces.
The plan called for regular flights between the Swan River, Perth, and Koggala Lake, in southern Ceylon (now Sri Lanka).
Qantas crews had gained experience with long over-water flights while ferrying 19 Catalina flying boats to Australia from San Diego, California.
The single Indian Ocean hop of 5,652km would be the longest non-stop regular passenger flight ever attempted in the world. Celestial navigation had to be used to maintain radio silence over waters patrolled by enemy aircraft. The weight of fuel limited the Catalina's load to only three passengers and 69kg of diplomatic and armed forces mail.
The first flight took place on 29 June 1943 under the command of Captain Russell Tapp.
The flying boats, travelling at about 200km/h, would take an average of 28 hours to complete the journey, but up to 32 hours nine minutes when winds were unfavourable.
By the time the operation ended on 18 July 1945, 271 crossings of the Indian Ocean had been completed using the Catalinas. They had carried 648 passengers and flown more than 1.5 million kilometres.
Converted Liberators and Lancastrians later supported services on the route.
The five Qantas Catalinas, supplied by the British Air Ministry, took their names from the stars used for navigation - 'Rigel Star', 'Spica Star', 'Altair Star', 'Vega Star' and 'Antares Star'.
They were so heavy with fuel on take-off that the failure of one engine in the first 10 hours of flight would have made a ditching inevitable. This never happened.
Meteorological information was confined to forecasts on local weather conditions at either end, but a meteorological office was later set up at Cocos Island for use in extreme need. Each passenger was given an illustrated certificate entitling them to membership in 'The Rare and Secret Order of the Double Sunrise', to attest that they had been airborne more than 24 hours.
At the end of the war the five Indian Ocean Catalinas were scuttled at sea under the lend-lease agreement with the US Government. It was, in the words of Hudson Fysh "a dismal fate for these splendid boats which for two long years saw us through our most hazardous operation ever without accident or mishap of any kind."
When the war was over Qantas acquired seven former RAAF Catalinas and used them for services to New Caledonia, New Hebrides, Fiji and Lord Howe Island.
Within New Guinea the Catalinas operated to remote, crocodile-infested lakes and rivers where tribesmen paddling log canoes would transfer passengers and cargo.
One Catalina was destroyed by sabotage while moored at Rose Bay, Sydney, on 27 August 1949.
Catalinas remained in service with Qantas until the last two were sold in November 1958.