astern -- (stern foremost or backward; "the steamer went astern at half speed")
aft, abaft, astern -- (at or near or toward the stern of a ship or tail of an airplane; "stow the luggage aft"; "ships with square sails sail fairly efficiently with the wind abaft"; "the captain looked astern to see what the fuss was about")
astern -- ((of a ship or an airplane) behind; "we dropped her astern on the end of a seven-inch manilla, and she laid comfortably on the ebb tide")