|This article needs additional citations for verification.
Please help improve this article by adding reliable references. Unsourced material may be challenged and removed. (June 2007)
The expedition was led by Spaniard Vital Alsar who, in 1970, led the La Balsa expedition, only on that occasion with one raft and three companions. The crossing was successful and, at the time, the longest raft voyage in history, until eclipsed in 1973 by Las Balsas.
The purpose of the 1973 expedition was three-fold - (1) to prove that the success of 1970 was no accident, (2) two test different currents in the sea, which Alsar maintained ancient mariners knew as modern humans know road maps, and (3) to show that the original expeditions, directed perhaps toward trade or colonisation, may have consisted of small fleets of balsa rafts.
The three rafts of the Las Balsas expedition ("balsa" is the Spanish word for raft) were named "Guayaquil" for point of departure, "Mooloolaba" for the intended point of arrival and "Aztlan", for the town in Mexico where the expedition first gathered.
The expedition consisted of twelve sailors (Alsar plus eleven others) and each raft had four crewman. Among the twelve were Americans Michael Fitzgibbons and Tom McCormick, and Gabriel Salas of Chile, who had sailed on the earlier expedition.
The rafts were each 46 feet (14 m) long and 18 feet (5.5 m) wide. They were constructed with seven balsa wood logs which were cut down in the jungles of Ecuador from female trees during the full moon when the sap content was at its optimum thus ensuring its resistance to saturation by sea water. They were then floated down river to the naval base at Guayaquil for construction. The rafts are entirely built from wood with wooden pegs and sisal ropes for rigging. They were not capable of turning around when being carried by currents could manoeuvre with the use of short planks between the logs called "guayas".
Each raft had a crew of four and included a cat, a monkey and two parrots. They carried enough water for 100 days and then had to rely on rain water. Canned meat and vegetables were stocked but they were to rely on sea food as their main diet. In the hot weather each man had to drink a pint of sea water each day to compensate for the lack of salt from dehydration. Each raft had a short range radio for use in emergency and enabled them to contact land every third day.
Setting sail from Ecuador they commenced their drift across the Pacific Ocean via the Galapagos Islands, The Society, The Cook Islands, Tonga, South of New Caledonia and then arrived off Mooloolaba. The weather was bad and the prevailing currents carried them down the coast to Ballina, New South Wales. HMAS Labuan followed their drift and it was decided to tow them into Ballina with the aid of local fishermen. One raft was breaking up and close to foundering so it was abandoned and left to drift on and was eventually washed up on the beach in Newcastle. After 9,000 miles (14,000 km) and 179 days at sea the crews were given a heroes' welcome by the people of Ballina.
Because Chile had come under military rule during the time of the voyage, both Gabriel Salas and the other Chilean crew member were personally offered refugee status by Australian Prime Minister Gough Whitlam.
The best parts of the remaining two rafts were combined to form one raft and Ballina Shire Council built a museum to house the combined raft. Each year thousands of world travellers are able to see this exhibition and marvel at this exploit of twelve men.