Ship Registry suggests Manxman 'design flaw'

Switch from oil to water lubricated bearing under spotlight

The Isle of Man Ship Registry has suggested the problems which have left Manxman out of action may be a design flaw, rather than an issue with Douglas Harbour.

It follows suggestions from the Steam Packet Company (SPC) that rocks and stones in the harbour are wearing out the bearings.

In an email from August, Principal Surveyor Chris Martin said the registry believed it was 'more of a design flaw in the vessel rather than an issue of what [is] in the harbour'.

He explained the vessel was originally meant to have oil lubricated stern tubes, but this changed to water lubricated bearings early in the project.

He also noted the Ben-my-Chree, which has a traditional oil lubricated system, had no such issues in 25 years of operation in Douglas Harbour.

The Ship Registry was asked for a 'high level view' on the issue after now-DEFA Minister Dr Rachel Glover highlighted during the election campaign that SPC Managing Director Brian Thomson had told candidates that Douglas Harbour is the likely cause.

Mr Martin said: "Whilst we are not party to the analysis of the worn shaft and bearing material, the argument regarding the problem being rocks and stones specifically related to Douglas would seem somewhat flawed.

"A new stern tube would have quite a small clearance between shaft and liner, which would not allow stones to enter, only much smaller particles would fit in this original clearance.

"Obviously once the wear increases to the extent that has been found, larger particles e.g. small stones etc would be able to enter and may have the potential to dramatically increase the wear.

"Bearing in mind all of the above we would consider that the issue is more of a design flaw in the vessel rather than an issue of what in the harbour. 

"Use of the well proven and traditional oil sealed stern tube bearing would be a better option than using a water lubricated bearing in the environment that the vessel operates in i.e. turning around and manoeuvring in shallow harbours four times a day.

"Whilst use of water lubricated bearing are on the increase, they may not be suited to certain types of vessels and trades."

The ferry operator said it is 'unable' to comment on discussions which took place between the Ship Registry and the Department of Infrastructure's director of harbours. 

They added: "On the Manxman repairs our latest information on the progress of these repairs is available on our website which we update on a weekly basis."

Manxman is currently showing as returning to service on Tuesday 1 December.