MSM DON - Maritime Incident
Vessel: MSM DON
GAMA reference: 2014-082
Data da ocorrência acidental: 26-03-2014
Circulated on: 20-08-2015
Published on: 23-09-2015
Summary
On 26 March 2014, during the approach to the port of Aveiro under pilotage, the rudder of MSM DON became restricted between 5 degrees port and hard port, with no possibility of turning to starboard. The turn initiated following a course alteration only stopped at 270 degrees. The Master aborted the port entry, anchored the vessel, and it was subsequently towed away from the port approach. An underwater inspection revealed contact between a bearing and the rudder blade. The Becker flap rudder system had previously been modified by the welding of six steel plates, altering its design and load distribution. The resulting deformation reduced the clearance and blocked rotation to starboard. There were no injuries, pollution or other damage.
Safety recommendations
No safety recommendations were issued in the final report.
Lessons learned
A failure in a steering system component does not necessarily mean that the original design should be fundamentally altered rather than repaired. Any temporary modification to the rudder should be subject to engineering assessment, approval, testing and in-service monitoring. Initial manoeuvring trials may not reveal progressive deformation caused by hydrodynamic forces and impacts. Clearances between moving and fixed components should be checked following repairs. Where rudder movement becomes restricted, cancelling the port entry, anchoring, and requesting tug assistance may prevent more serious consequences.