In 1850 the South Australian government had offered a bonus of £4,000 to be equally divided between the owners of the first two iron steamers that should successfully navigate the Murray from Goolwa to the junction of the Darling River. When Cadell returned to Australia in 1852, he arrived at Port Adelaide in command of the clipper "Queen of Sheba". The government's bonus for the navigation of the Murray River had not been claimed and Cadell stayed in Adelaide, formulating a design for a suitable steamboat in partnership with his father's agent, William Younghusband.