Objects dropped from pipelay tower

A member has reported an incident in which two objects fell from a pipelay tower. The incident occurred some four weeks after repairs to a 360Te winch wire garage at the top of the pipelay tower. These repairs had involved the erection of scaffolding 50-60m above the deck in the pipelay tower, removal of the garage assembly, repair and reinstallation.

During operations four weeks later a shaft weighing 1kg and shaft end cap weighing 500g fell approximately 57m to the mobile work platform below. There were no injuries.

Our member’s investigation noted the following:

• During the earlier reinstallation of the garage assembly, the securing bolts for the shaft end cap were installed without any means of thread locker (Loctite). This resulted in the bolts for one of the shaft end caps vibrating loose, resulting in the shaft being unrestrained and free to vibrate out along with the end cap;
• There was no written work instruction or method statement for the earlier corrective maintenance;
• There was no means of securing the end cap retaining bolts other than the torque of the bolt itself in the shaft;
• The drawings for the garage assembly and parts list did not reference the use of thread locker;
• The garage assembly was not listed on the vessel asset equipment register and therefore no maintenance was assigned to it.

The following actions were taken:

• Use of secondary means of securing fasteners for all equipment, particularly at height;
• Checked security and integrity of remaining fasteners;
• Fasteners cleaned, torqued to the correct value, thread locked (Loctite) and wire moussed;
• Equipment entered into the appropriate asset equipment register and planned maintenance scheduled;

Members are reminded of IMCA promotional material as follows:

• Avoiding dropped objects (pocket card)
• Avoiding dropped objects (poster)

Members may wish to refer to the following similar incidents (key words: dropped, object, pipelay, tower):

• Near-miss: Dropped object
• High potential dropped object