 They managed to survey the Mare Island Strait before steaming to Hawaii to obtain crewmen from Hawaiian monarch King Kamehameha III.They returned to San Francisco in the spring of 1850 with the coastal survey of northern California beginning on 4 April 1850 and continued up to the mouth of the Columbia River.On 1 August 1850, while still in Oregon, McArthur purchased a interest in Mare Island for $468.50 then returned to San Francisco later that month to prepare charts and write reports.