Douglas Harper's Etymology Dictionary
1832, from stern (n.) + -ward.
Wiktionary
a. Towards the stern, aft. adv. sternwards
Usage examples of "sternward".
Out into the access tunnel, three meters across, a geometric tube of blue striplights and handholds two hundred meters sternward of her feet.
He kicked the shore fast free and hopped onto the vessel's bow, then ran sternward along the gunwale to join Sharina.
Metal screamed as a huge spring shot sternward along a track, pulling on the rope to the primary gyroscopic stabilizer.
Sternward, men with a hand kiln were recoating a beam that had been ground down to remove the surface crazing.
The whole boat jerked sternwards abruptly with the recoil, as though when underway she had struck a rock, and the smoke came back round them in a sullen pall.
I could hear the words echoing from tannoys in the compartments sternward.