Instead of using a lifting frame with a 4 leg wire arrangement and 1 crane hook (normal when lifting big boats), they use 2 crane hooks, and only a transverse beam on each sling. When the boat rotates, the 2 crane hooks moves such that the distance between them are reduced, forcing the slings to move towards each other, eventually causing the boat to slide out.
It could have easily been solved by securing the position of the slings to the boat by ropes. Normaly you would also have a person on the ground (deck of cargo ship in this case), holding a rope tied to the boats bow puller, controlling the boats movement. This persons would easily manage to stop any rotation, and thereby avoiding the fatal accident.
slings got nothing 2 do with it i think the fact its swung back on 2 dock and crane operator kept lowering winch and the boat fell out off slings would b more likely watch it again with your glass,s on goods
improper location of slings.note that the front pullyblock has a rearward tension on it thus pulling the front sling back causing boat to be unbalanced ...the crane operator should of noticed that right off the bat.Nothing broke at all! just poor loading.Guy should stick to forklifts :)...tho common sence is needed in all aspects of life :p