American whaler Improvement departed to sea in 1817

Of Nantucket, master Obadiah Coffin, departed on 7 September 1817 to the Pacific Ocean and returned on 8 December 1819 with 1.527 barrels sperm and 50 barrels whale. 

Source
Catalogue of Nantucket Whalers and their voyages from 1815 to 1870. Hussey&Robinson, Nantucket, 1876.