Re: Picture Quiz
Posted: Sun Nov 21, 2010 4:14 pm
Yeah JK,
You got it.
They park the crane jib on its crutch & lower the hook down to the platform, loop the old mooring rope over the crane hook and the hoist the hook until everything is bar tight.
Not a good idea to leave the crane parked with all that tension on the wire, the hydraulic winch or the sheeves and associated bearings.
The tension pulls the crane jib down and puts a bending moment on it.
The tension on the wire is also destroying the layer of wood at the bottom of the crutch, the wood has to be replaced regularly, because it is crushed into splinters.
The parking limit switch, fitted where the jib sits in the crutch is also broken, regularly, because the jib is forced into a lower position than it should be.
You have already spotted the cracks in and adjacent to the welds and in the gussets, and the fact that the deck where the hook is attached has bowed upwards, both in the fore & aft and athwartship directions, buckling the stiffeners below.
The crutch for the jib is at the top of the tower and the platform that the hook is secured to is half way up, so the tension in the wire puts the entire top half of the tower into compression, but it was only designed to support the inert weight of the crane jib, not several tonnes tension as well, so the whole structure is severely overloaded.
I pointed all this out to the Chief Officer who told me it must be correct because that is what they do on the other 4 ships in the Class.
I explained it to both Captains that I sailed with during the 4 month hitch, both claimed to unsderstand and promised to do something about it, but nothing happened.
I also found a Superintendants Inspection Report for the ship ordering the rope to be replaced with a thinner one, this had been signed off as done, but nothing was changed, typical "tick box" culture.
All very frustrating.
BP
You got it.
They park the crane jib on its crutch & lower the hook down to the platform, loop the old mooring rope over the crane hook and the hoist the hook until everything is bar tight.
Not a good idea to leave the crane parked with all that tension on the wire, the hydraulic winch or the sheeves and associated bearings.
The tension pulls the crane jib down and puts a bending moment on it.
The tension on the wire is also destroying the layer of wood at the bottom of the crutch, the wood has to be replaced regularly, because it is crushed into splinters.
The parking limit switch, fitted where the jib sits in the crutch is also broken, regularly, because the jib is forced into a lower position than it should be.
You have already spotted the cracks in and adjacent to the welds and in the gussets, and the fact that the deck where the hook is attached has bowed upwards, both in the fore & aft and athwartship directions, buckling the stiffeners below.
The crutch for the jib is at the top of the tower and the platform that the hook is secured to is half way up, so the tension in the wire puts the entire top half of the tower into compression, but it was only designed to support the inert weight of the crane jib, not several tonnes tension as well, so the whole structure is severely overloaded.
I pointed all this out to the Chief Officer who told me it must be correct because that is what they do on the other 4 ships in the Class.
I explained it to both Captains that I sailed with during the 4 month hitch, both claimed to unsderstand and promised to do something about it, but nothing happened.
I also found a Superintendants Inspection Report for the ship ordering the rope to be replaced with a thinner one, this had been signed off as done, but nothing was changed, typical "tick box" culture.
All very frustrating.
BP