The Collaborative International Dictionary
stern chaser
Chaser \Chas"er\, n.
One who or that which chases; a pursuer; a driver; a hunter.
(Naut.) Same as Chase gun, esp. in terms bow chaser and stern chaser. See under Bow, Stern.
Wiktionary
stern chaser
n. A gun or cannon mounted on the stern of a ship for firing at a pursuing vessel.
WordNet
stern chaser
n. a naval gun able to fire astern at a ship in chase
Usage examples of "stern chaser".
Trained back over the stern the cannon could now be used as a stern chaser to bring the Arcturus under fire as soon as she drew within range.
Another shell, hard on the heels of the first, but from the stern chaser, ploughed into the embankment before exploding, harming no men.