USS Stein Sonar Dome Incident

Background

On patrol off the San Diego coast in 1978, the USS Stein, a Dealey-class destroyer escort (hull number DDE-33), suffered unusual and significant damage to its newly installed AN/SQS-26 sonar dome. The sonar system had been a recent upgrade, designed with a reinforced rubber "NOFOUL" coating to withstand pressure, debris, and marine life encounters. During what appeared to be routine operations in the Pacific Ocean, the ship's sonar suddenly failed. Upon returning to port for inspection and repairs at Naval Base San Diego, engineers made a startling discovery.

The Damage

Approximately 8% of the sonar dome's rubber coating had been severely shredded. Large curved claw or hook marks, some measuring up to two to four feet in length, scarred the dome's surface. What made the damage particularly significant was that many of these gouges contained embedded objects—chitinous hooks or claws—arranged in arc patterns as if something had wrapped around the dome and dug in with considerable force. The damage pattern and depth suggested deliberate contact rather than accidental collision with debris.

The rubber coating, which had been designed to resist corrosion and marine impact, bore witness to something with extraordinary strength and unusual appendages. Navy technicians and engineers examined the embedded hooks closely, finding them to be unlike anything documented in standard marine biology literature available to the Navy at that time.

Naval Investigation

The Navy dispatched marine biologist Forrest G. Wood to analyze the claw marks and embedded objects. Wood's conclusion was that the marks and embedded hooks were consistent with cephalopod appendages—specifically, the chitinous hooks found on squid tentacles, particularly those lining the rims of suction cups on species of very large squid. The hooks were significantly larger than any reported specimens in scientific records at the time, and their arrangement and depth of penetration suggested a creature of extraordinary size and strength.

Wood concluded that the damage could have been inflicted by a single large squid, possibly a colossal squid (Mesonychoteuthis hamiltoni), a deep-sea cephalopod known to inhabit waters far deeper and colder than those off San Diego. The Navy accepted this conclusion and repaired the sonar dome, restoring the ship to full operational capability.

The Mystery

While the Navy's official explanation centered on a giant or colossal squid encounter, several aspects of the incident remained unexplained. Most notably, deep-sea squid of the size implied by the damage are typically found in Antarctic and sub-Antarctic waters, far from the coastal waters of Southern California. Additionally, no visual confirmation of any creature was made by the crew, and no reports of the creature breaching the surface or being sighted exist.

The peculiarity of the encounter—a massive deep-sea creature far from its known habitat, attacking a military vessel with apparent deliberation, leaving behind physical evidence that defied easy classification—attracted attention from UFO and UAP researchers. Some have suggested the incident as a potential case of underwater unidentified activity (USO), theorizing that the damage could have been caused by an unknown submersed object rather than a known marine creature.

Interpretations

Scientific Explanation: Navy and marine biology authorities concluded the damage was consistent with a giant or colossal squid attack, likely defensive in nature. The creature was presumed to have mistaken the sonar dome for prey or a territorial threat.

Alternative Theory: UFO/UAP researchers have cited the incident as evidence of underwater unidentified activity, noting the unexplained nature of why such a creature would surface in an atypical location, the lack of visual confirmation, and the deliberate nature of the attack.

The USS Stein incident remains one of the few documented cases of a military vessel sustaining damage attributed to an encounter with an unknown or misidentified marine creature, bridging the gap between marine biology and UFO research.