John Borland "Jack" Thayer III (December 24, 1894 – September 20, 1945) was a first-class passenger on RMS Titanic who survived the ship's sinking.

Noticing that the ship was beginning to list to port, they returned to their rooms to put on warmer clothes and life vests.

[2][3] As the ship began listing more, the two men went ahead with attempting to jump off the side, intending to swim to safety.

He and other crew and passengers, including Junior Wireless Officer Harold Bride, Colonel Archibald Gracie IV, Chief Baker Charles Joughin, and Second Officer Charles Lightoller (who was the most senior surviving crew member), were able to keep the overturned boat steady for some hours.

Thayer later recalled that the cries of hundreds of people in the water reminded him of the high-pitched hum of locusts in his native Pennsylvania.

[1] In his privately published 1940 account of the sinking, Thayer recalled what life was like before the Titanic sank, "There was peace and the world had an even tenor to its way.

It seems to me that the disaster about to occur was the event that not only made the world rub its eyes and awake but woke it with a start keeping it moving at a rapidly accelerating pace ever since with less and less peace, satisfaction and happiness.

The couple had two sons, Edward Cassatt and John Borland IV, and three daughters: Lois, Julie, and Pauline.

In 1939, Thayer became treasurer of the University of Pennsylvania, and was appointed to the newly created office of financial vice president in February 1944, a position he held until his death in September 1945.

[1][6] Oceanographer Robert Ballard used Thayer's account to help determine the final resting place of the shipwreck.