Outline:When the exhaust valve of the main engine had to be lifted up using the engine room crane and chain block, the chain block was connected to the engine room crane in series, and the crew members were intending to try and tighten and slacken the chains using the engine room crane.
Never hoist objects using the E/R crane in series!!!
When you use more than 2 hoists in series, the hoist with the lightest load limit must be operated in the proper way and within the weight limit of the hoist and/or wire.
source: MOL Safety Alert File No. MRN(E)-SA-11/009