This drawing shows a drua (double-hulled sailing canoe). The drua is a boat design thought to be a combination of Polynesian and Micronesian techniques. The drua could travel at speeds up to 25 knots in good weather conditions. In Tonga it was known as the kalia, and as the alia in Samoa.
The construction of drua required a lot of time and resources. Rich chiefs would typically employ a tribe of master boat-builders to build them, with the construction of larger boats taking over two years and being dependant on the supply of construction materials by the chief. The drua were considered sacred and on their first entry into the water would demand blood, so rollers of human slaves, alternating with banana stems, would be used to move them as part of their initiation ceremony.