On 26 Jul 1943, the John A. Poor (Master William J. Uppit) sailed from Boston to Halifax with 8500 tons of general cargo in station #14 of the convoy BX-65, but lost contact in heavy fog. The ship streamed her anti-torpedo nets and continued alone at 8 knots, wandering into mines laid on 1 June by U-119 (von Kameke) in 42°51N/64°55W (grid BB 75). At 10.30 hours on 28 July, a heavy concussion occured off the starboard side, the ship suffered only minor damage and continued her voyage. One hour later another explosion occurred off the starboard side, and the master, thinking he saw a U-boat, turned the vessel. 15 minutes later a violent explosion damaged the steam lines, the boilers, the generators, cracked the spring bearings and stopped the vessel, but there was no hull damage. The armed guards fired the guns (the ship was armed with two 3in and eight 20mm guns) at a nonexistent enemy. The eight officers, 34 crewmen and 28 armed guards remained on board, one crewman was injured when he was blown off the generator platform into the bilges and had to be hospitalized at Halifax.
At 18.30 hours, the patrol boat #123 came alongside and informed the master that tugs were en route, but the watch below got one boiler lit and the vessel proceeded under own power at 4,5 knots after the torpedo nets were retrieved. 30 minutes later, the tug North Star took her in tow, but the 300 HP towboat was not powerful enough for towing a ship of this size, so the vessel continued under her own power. At 17.50 hours, the tug Foundation Aramore took over the vessel 45 miles off Sambro Light and towed her to St. George Island, Halifax, arriving on 31 July.

The John A. Poor was repaired and eventually arrived in Avonmouth via St. Johns. She did not get back to the US until 12 Nov 1943 when the ship arrived at Philadelphia.

At 19.45 hours on 19 March 1944 the John A. Poor (Master Francis Wallace Dulac) was hit by two torpedoes from U-510 in the Arabian Sea. The ship had been in a coastwise convoy, but left convoy at 21.45 hours on 18 March and sailed independently on a zigzag course at 12 knots. The first torpedo struck on the starboard side between #4 and #5 holds. The explosion blew off the #4 hatch cover and created a hole about 12 feet in diameter in the deck. The second struck in the #5 hold. The vessel immediately listed to starboard and settled rapidly, sinking within two minutes.

No lifeboats could be launched, only the four rafts cleared the ship. Nearly half of the eight officers, 35 crewmen and 30 armed guards (the ship was armed with two 3in and eight 20mm guns) went down with the ship, including the master. One officer, 17 crewmen and 21 armed guards reached three rafts, lashed them together and rigged a sail.

The survivors were picked up on 22 March by the British steam merchant Fort Walsh and landed at Colombo, Ceylon, four days later.