[5][6] As the founding Chairman of the International Committee on the Underwater Cultural Heritage (ICUCH) he played a role in initiating development of a first draft for the UNESCO 2001 Convention_on_the_Protection_of_the_Underwater_Cultural_Heritage.
[15] In December of that year, at the suggestion of Phillip Playford, the Henderson family and John Cowan passed their rights as discovers of the wreck to the Western Australian Museum.
[16] In the following year the State of Western Australia proclaimed the Museum Act Amendment Act of 1964, protecting the Dutch East India Company ships Vergulde Draeck (1656), Batavia (1629), Zuytdorp (1712), and Zeewijk (1727), together with the English East India Company ship Tryall or Trial (1622), and what was called the "Cottesloe wreck", then thought to be a Dutch or Portuguese wreck dating around 1600 (later shown by Henderson to be the Elizabeth).
[17] This 1964 Act was the precursor to all Australian shipwreck legislation and led directly to the establishment of maritime archaeology in Western Australia and later across the nation.
[19] After being appointed Head of the Colonial Shipwrecks unit Henderson led major expeditions and research into the English whaler Lively (c1806) on the Rowley Shoals, the American China-trader Rapid (1811) on the Ningaloo coast, the regional trader Elizabeth (1839), the ex-slaver James Matthews (1841) in Cockburn Sound, and the emigrant barque Eglinton (1852) off the Perth suburb of Eglinton.