The flag is dated 1845–1849 and may have continued to the end; the Coffin owners also had house flags. A painting of 1840–1850 whaling signals is cited.
Edward Cary operated from Nantucket in 1841–1859, then was sold to San Francisco. Charles G. Coffin is named as owner in 1845 and Henry Coffin in 1858; other owners are unknown. Agents included James Ahearn, C.G. & H. Coffin and G. & M. Starbuck.
Keep the explicit scope label independent; no alias or company identity is inferred.