The phrase "astern of the" is correct and usable in written English.
It is typically used in nautical contexts to describe a position behind a vessel or object.
Example: "The lifeboat was located astern of the main ship, ready for any emergency."
Alternatives: "behind the" or "at the rear of the".
Then at 6 55 pm he ordered another 180° turn, possibly in the hope that he would pass astern of the main British line.
Britain, which ended a 15-year absence from the America's Cup, finished only four boat lengths astern of the far more experienced Conner team.
Midway through the race, Isler and Glaser were mired in ninth place and sailing astern of the Australians, Israelis and Ukrainians, who were directly in their path to the medal podium.
But with two-thirds of the current event completed, MacArthur is in second place and barreling along, about 300 miles astern of the leader, Michel Desjoyeaux, aboard the yacht PRB.
In common with the ketch, the forward (main) mast is higher than the mizzenmast, but the mizzenmast of a yawl is placed astern of the rudder post, while that of the ketch is closer amidships.
Twice, at least, Captain Truxtun attempted to maneuver his ship into a raking position, once ahead and once astern of the enemy, but each time the French captain anticipated his move and was able to avoid being raked.
Despite being two-thirds the size of the black behemoth, Giacomo was a mere two hours astern of Loyal over the 628 nautical mile course.
Friedrich der Grosse was the last ship in her division, directly astern of and ahead of, the flagship of Vice Admiral Schmidt's I Division, I Battle Squadron.
While being passed astern one of the boats broke the painter and became adrift.
Posen was now the fourth ship in the line, astern of her three sisters.
The ship astern of Montagne, Jacobin, attempted to prevent Queen Charlotte breaking through by accelerating to close the gap between herself and her flagship; this left a gap behind her, between Jacobin and Achille, that HMS Brunswick, under Captain John Harvey, attempted to exploit to cut the line and assist Queen Charlotte.
