Once I experienced an incident involving chain blocks.

We had a problem in our shaft generator and the rotor of gennie was to be removed, and sent ashore for repair. We planned to dismantle the genie by keeping it in a vertical position. For that we decided to hang 3 chain blocks above the Gennie on a rigid frame. And slings and chain blocks were hung in 3 different positions.

And we found it would not be possible to lift and tilt the Gennie if chain blocks are arranged in this way. So we decided to hang two chain blocks together. The Fitter and a motor man took some additional slings and shifted the position of the chain blocks. As they had left the chain blocks on typically arranged slings and shackles both chain blocks came out of the hooks and fell down, injuring the 5th Engineer who was standing right underneath.

The reason for this accident was that the chain block did not have a safety locking arrangement on the block hook.