The U.S. Coast Guard (USCG) issued a safety warning after a prototype component used in a mechanical shaft-seal system failed onboard a U.S. Coast Guard–inspected deep draft vessel.
On February 19, 2025, a U.S.-flagged crude-oil tanker transiting near Delaware Bay experienced simultaneous failures of its port and starboard shaft seals, leading to substantial seawater ingress. The crew deployed emergency collars supplied by the seal manufacturer and used the vessel’s emergency bilge system to remove the water, but an investigation later identified the failed component as a prototype composite seal-facing material installed during dry-dock as part of a shaft-seal system previously approved by a Recognized Organization (RO).
The investigation found the RO-approved design drawings lacked specific material details and described the seal-facing material only as “composite,” while the seal manufacturer did not disclose its use of the unapproved prototype material. During the vessel’s first post-dry-dock voyage, seawater flooded through the seals’ split face butt when exposed to cold seawater after operating in warm conditions; the USCG, the RO, and the vessel owner became aware of the substitution only after the incident occurred.