She spent several years as a government transport, and then between 1830 and 1836 she made two voyages as a whaler in the Britishsouthern whale fisheryy.

[1] 1st whaling voyage (1830–1832): Captain A.Gray (or Grey), sailed from England on 29 June 1830.

Thetis was reported to have been on the Japan Grounds, and at Honolulu.

[3] 2nd whaling voyage (1832–1836): Captain Apsey sailed from London on 16 October 1832.

Aspey, after his return, went on to captain Harriet, another vessel that Somes owned, sailing her on a whaling voyage to New Zealand.