So engaged on the evening of June 1, 1973, the vessel was involved in a disastrous collision with the oil tanker Esso Brussels in lower New York Harbor and was damaged so badly that she was removed from active service.

Both the captain's and the pilot′s attempts to regain control of Sea Witch proved futile, as both the port and starboard steering systems were connected into a single mechanism atop the vessels rudder post by a faulty "key," a device similar to a cotter pin, which had failed.

[citation needed] Less than five minutes had passed from the initial loss of steering control aboard Sea Witch before she was within a ship′s length from Esso Brussels′ midship, and with the ship still making 13 knots with her engines in full reverse and a collision now unavoidable, Cahill and Paterson ordered the crew off the bow and abandoned the forward superstructure.

Aboard Esso Brussels, the 36-member crew had roughly two minutes′ warning of the impending collision before the sharply raked bow of Sea Witch, heavily reinforced for operations in icy harbors, rammed into the tanker at 0042 hours.

During this time, the still-engaged engines of Sea Witch began to pull the two ships into the center of the Narrows, where the burning pool of oil sent flames high enough to scorch the bottom of the Verrazzano-Narrows Bridge 228 feet (69 m) above the water's surface.

Moving toward the stern of Sea Witch in an attempt to look for survivors, Fire Fighter and her crew found the entire ship enveloped by the burning slick and much of the after superstructure heavily aflame.

[citation needed] Aboard Sea Witch, the 31 surviving crewmen had been trapped in the rear cabin for more than half an hour, enduring dozens of close-quarter explosions from the ship's cargo and temperatures so high that the crew was forced to spray the surrounding bulkheads with water in order to stave off being baked to death.

Initially ordered to use their maximum pumping capacity to snuff the heavy flames still burning aboard Sea Witch, the fireboat fleet was called off after the ship developed a 25° list to port and threatened to capsize.