Small movements – big impact

Royal Caribbean’s engine problems created a major headache for MAN B&W’s medium-speed operation.

For the first two or three years all went well. The MAN B&W 12V48/60 engines aboard Grandeur and Enchantment of the Seas performed well – then things started to go wrong. In February The Motor Ship broke the news that Grandeur suffered engine problems, and in March things got worse as an engine on Enchantment failed, wrecking the block and reducing the ship to emergency power for 45 minutes. As another of its four engines was already out of commission, Royal Caribbean decided to bring forward the planned overhaul and pulled the ship out of service for six weeks to allow repairs to be carried out.

On inspection it was obvious that the connecting rod head (containing the piston pin bush) had fractured and the free end of the rod had wrecked the block. What was not clear at this stage was why it had happened. Stress calculations showed that there was ample strength, so something else must have started the fracture. In Augsburg a task force was hastily assembled to investigate the cause.