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Troubled Ferry Glen Sannox Pulled From Service Over Repeated Cracking

Glen Sannox (CalMac / Ferguson Marine)
Glen Sannox (CalMac / Ferguson Marine)

Published Oct 9, 2025 8:24 PM by The Maritime Executive

 

CalMac's ill-starred ferry Glen Sannox is suffering repeated hull cracking issues just eight months after delivery, and the problem is related to an unresolved and severe vibration issue in her propulsion system, according to Scottish paper The Herald. 

It has been a long road for the Glen Sannox project, and an illustration of the difficulties of starting a national shipbuilding program. Shipyard Ferguson Marine started work on the CalMac ferry in 2015, went bankrupt after serious design flaws emerged, and was nationalized in 2019. After a long saga of rework, budget hikes and personnel changes, the ferry finally entered service in January 2025, six years behind schedule and four times over budget. It has been in and out of repair status ever since.  

In March, Glen Sannox was pulled from service after a five-inch-long hairline crack was discovered in a weld seam on the hull, in way of the steering gear compartment near the waterline. Repairs were completed shortly after, and following a dive inspection the ferry was cleared to sail again. 

Last week, a new crack was discovered in the same area, and the Glen Sannox has been pulled from service through at least October 13. The Herald reports that CalMac is consulting with marine engineering experts at home and abroad in search of a permanent solution. The crack is believed to be caused by a vibration issue in the same specific area. 

Passengers confirmed that the ship had severe vibration at the stern during certain evolutions. "Anyone who has been on the ship, particularly in the aft end of passenger space while maneuvering, could have worked that out," commented passenger Sam Bourne, a local resident, in a social media post. "It was vibrating so badly it would literally shake the coffee out of your cup."

One passenger video shows the rails of a ladderway visibly shaking from heavy vibration near the stern.

The source of the vibration has not been published, but the Herald reports that it is related to a propeller issue. Glen Sannox is fitted with a stern thruster to help handle strong currents and winds on the beam, and she has twin controllable pitch propellers.