"food" in general, but in dialect especially "bad food," and especially among sailors "food of a bread kind," 1833, perhaps a shortening and special use of tackle (n.) in the sense of "gear." But compare tack "taste" (c.1600), perhaps a variant of tact.

"turn a ship's course toward the wind at an angle," 1550s, from tack (n.1) in the ship-rigging sense (the ropes were used to move the vessel temporarily to one side or another of its general line of course, to take advantage of a side-wind); hence tack (n.) "course of conduct or mode of action suited to some purpose" (1670s), from figurative use of the verb (1630s). Related: Tacked; tacking.