On Tuesday, 15 September 1942, the carriers Wasp and Hornet and battleship North Carolina with 10 other warships were escorting the transports carrying the 7th Marine Regiment to Guadalcanal as reinforcements. Wasp was operating some 150 nautical miles (170 mi; 280 km) southeast of San Cristobal Island. Her aircraft were being refueled and rearmed for antisubmarine patrol missions and Wasp had been at general quarters from an hour before sunrise until the time when the morning search returned to the ship at 10:00. Thereafter, the ship was in condition 2, with the air department at flight quarters. The only contact with the Japanese that day had been a Japanese four-engined flying boat that was downed by one of Wasps F4F Wildcats at 12:15.
About 14:20, the carrier turned into the wind to launch eight F4F Wildcats and 18 SBD Dauntlesses and to recover eight F4F Wildcats and three SBD Dauntlesses that had been airborne since before noon. Lt. (jg) Roland H. Kenton, USNR, flying a F4F-3 Wildcat of VF-71 was the last aircraft off the deck of Wasp. The ship rapidly completed the recovery of the 11 aircraft before turning to starboard, heeling slightly as it did so. At 14:44 a lookout reported “three torpedoes … three points forward of the starboard beam”.
A spread of six Type 95 torpedoes were fired at Wasp at about 14:44 from the tubes of the B1 Type submarine I-19. Wasp put over her rudder hard to starboard to avoid the salvo, but it was too late. Three torpedoes struck in quick succession about 14:45; one actually broached, left the water, and struck the ship slightly above the waterline. All hit in the vicinity of the ship’s gasoline tanks and magazines. Two of the spread of torpedoes passed ahead of Wasp and were observed passing astern of Helena before O’Brien was hit by one at 14:51 while maneuvering to avoid the other. The sixth torpedo passed either astern or under Wasp, narrowly missed Lansdowne in Wasp‘s screen about 14:48, was seen by Mustin in North Carolina‘s screen about 14:50, and struck North Carolina about 14:52.
There was a rapid succession of explosions in the forward part of the ship. Aircraft on the flight and hangar decks were thrown about and dropped on the deck with such force that landing gears snapped. Aircraft suspended in the hangar overhead fell and landed upon those on the hangar deck; fires broke out in the hangar and below decks. Soon, the heat of the intense gasoline fires detonated the ready ammunition at the forward anti-aircraft guns on the starboard side, and fragments showered the forward part of the ship. The number two 1.1 in (28 mm) mount was blown overboard.
Water mains in the forward part of the ship had been rendered inoperable meaning no water was available to fight the fire forward, and the fires continued to set off ammunition, bombs, and gasoline. As the ship listed 10-15° to starboard, oil and gasoline, released from the tanks by the torpedo hit, caught fire on the water.
Captain Sherman slowed to 10 knots (12 mph; 19 km/h), ordering the rudder put to port to try to get the wind on the starboard bow; he then went astern with right rudder until the wind was on the starboard quarter, in an attempt to keep the fire forward. At that point, flames made the central station unusable, and communication circuits went dead. Soon, a serious gasoline fire broke out in the forward portion of the hangar; within 24 minutes of the initial attack, there were three additional major gasoline vapor explosions. Ten minutes later Sherman decided to abandon ship as the firefighting was ineffectual. Survivors would have to disembark quickly to minimize loss of life.
After consulting with Rear Admiral Leigh Noyes, Captain Sherman ordered “abandon ship” at 15:20. All badly injured men were lowered into rafts or rubber boats. Many unwounded men had to abandon ship from aft because the forward fires were burning with such intensity. The departure, as Sherman observed it, looked “orderly”, and there was no panic. The only delays occurred when many men showed reluctance to leave until all the wounded had been taken off. The abandonment took nearly 40 minutes, and at 16:00 Sherman abandoned the ship once he was satisfied that no survivors were left on board.
Although the submarine hazard caused the accompanying destroyers to lie well clear or to shift position, they carried out rescue operations until Laffey, Lansdowne, Helena, and Salt Lake City had 1,946 men embarked. The fires on Wasp, drifting, traveled aft and there were four violent explosions at nightfall. Lansdowne was ordered to torpedo the carrier and stand by until she was sunk. Lansdowne‘s Mark 15 torpedoes had the same unrecognized flaws reported for the Mark 14 torpedo. The first two torpedoes were fired perfectly, but did not explode, leaving Lansdowne with only three more. The magnetic influence exploders on these were disabled and the depth set at 10 feet (3.0 m). All three detonated, but Wasp remained afloat for some time, sinking at 21:00. 193 men had died and 366 were wounded during the attack. All but one of her 26 airborne aircraft made a safe trip to carrier Hornet nearby before Wasp sank, but 45 aircraft went down with the ship. Another Japanese submarine, I-15, duly observed and reported the sinking of Wasp, as other US destroyers kept I-19 busy avoiding 80 depth charges. I-19 escaped safely.