After 1853, while still continuing to have the supervision of the computing department, he was frequently detailed for work of special importance or difficulty, such as the measurement of bases, the testing and discussion of the errors of instruments, etc. On March 31, 1854, while engaged in work on the Dauphin island base, the schooner Phoenix, with the entire party on board, was capsized in a squall and sunk to the topmast, on which the party took refuge, afterward escaping in a boat at considerable peril of their lives. Among his work of this year was the perfecting of a reflecting signal vane revolved by the wind, very simple and effective, and extensively used since.