201835 Dropped object close call

 

 

Edited from Marine Safety Forum 17-12

A rig supply vessel was under a rig. A tank was being repositioned on the aft deck, using the rig’s crane. During the repositioning, the bottom of the tank made contact with the cargo rail, tilting and rocking it. This caused one of the top gratings to fall from a height of about 6m on to the vessel’s deck. Two deck crew were some 15m forward from the dropped grating, which weighed 17kg. The potential consequence of being hit by a 17kg object falling 6 metres is lethal.

The gratings are intended to be fixed in place with four bolts and butterfly clips. On subsequent investigation, it was found that all four clips appeared slack on the side the grating fell from. One of the clips was also bent.

Lessons learned
- Always stand clear of lifted objects.
- Check the load before lifting; is everything secure?
- As the Drops Calculator* shows, even a mass as small as 1kg dropped from a height of about 12m can be lethal.
* See the Dropped Objects Prevention Scheme at www.dropsonline.org

The Drops Calculator has some important caveats:
- It is a guide, a cursory indication of a possible outcome
- The calculator is best employed proactively during risk assessments/task planning/time outs
- Assumes blunt force trauma, so not compatible with sharp objects
- Assumes full PPE is being worn
- The height of an individual should not be subtracted
- Never assume dropped objects will always strike the head.