What does abaft mean?
The definition of abaft
A*baft”, prep.
Etym: [Pref. a-on + OE. baft, baften, biaften, AS. beæftan; be by + æftan behind. See After, Aft, By.] (Naut.)

Behind; toward the stern from; as, abaft the wheelhouse. Abaft the beam. See under Beam.

A*baft”, adv. (Naut.)
Toward the stern; aft; as, to go abaft.