The U.S. Coast Guard has issued a safety warning after a prototype component in a mechanical shaft-seal system failed aboard a USCG-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, resulting in 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.

The investigation found the failed component was a prototype composite seal-facing material installed during dry-dock as part of a system previously approved by the vessel’s Recognized Organization. The approved design drawings described the material only vaguely as “composite,” and the manufacturer never disclosed its use of the unapproved prototype material — the Coast Guard, the RO, and the vessel owner learned of the substitution only after the incident.

In response, the USCG is recommending that Recognized Organizations require detailed material descriptions in approved drawings, verify material certification during inspections and surveys, and improve oversight of supplier quality control. Manufacturers are reminded to inform owners and operators of any deviations from existing approvals before installation.

Select the link to learn more.