Picture Quiz

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Big Pete
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Re: Picture Quiz

Postby Big Pete » 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
It is always better to ask a stupid question than to do a stupid thing.

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JK
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Re: Picture Quiz

Postby JK » Tue Nov 23, 2010 7:17 am

When I first looked at your pictures, I thought that the platforms and ladders were an add-on to an engineered crane crutch. I am still leaning that way.

You can almost hit play on the recorder and hear the stock replies to your concerns:

But we always did it
They do it on the other ships
It was like that when I got here
You're being too tough
Class approves it

and on and on.


My Dad was a longshoreman unloading the banana and date boats, before containerization. As a youngster , what stuck in my mind was the stories of the size of the spiders and other assorted insect life in with the cargo! THere were no dates in our house, Dad wouldn't touch them!

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Big Pete
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Re: Picture Quiz

Postby Big Pete » Wed Nov 24, 2010 1:18 am

Hi JK,
You are probably right about the "add ons" to the original structure I never checked that on the original plans while I was on board. I never really saw the point of the bottle screw. The jib was sitting in a crutch and the crane was hydraulically operated, so with the power off, the hoisting and slewing valves would be closed, hydraulically locking everything in place.
I suspect that a smaller rope for securing the crane hook would have broken before the safety valves lifted on the hoist winch, and that is why they were using the old mooring rope.
I was never a "Monkey see, monkey do" Engineer, I always try to look at first priciples and the Instruction Manuals for the truth, what other people do, and what has "always been done" etc should only be for initial guidance, but a lot of people never look at the underlying Engineering principles or read the manuals.
You mentioned the Portholes. lots of them leaked when it rained, margarine and ice cream tubs in the Port boxes to catch the water. One of the Superintendants Inspection Reports told the Chief Officer to order and fit new rubber seals to the Ports.
The Chief Officer decided it would be easier to cover the outsides with Silicon Sealant and paint over them. He didn't clean the paintwork first so the Silicon didn't stick properly and they all still leaked. He couldn't understand why the screw heads on the internal glass retaining plates were popping.
I had to explain to him that water was leaking between the glass and the metal frame, the frame was corroding, the rust had a bigger volume than the original steel, and the expansion was forcing the glass into the ship and popping the heads of the screws.
The Port openings also had a problem with rust build up underneath the seals between the fixed frames and the opening frame.
The solution is to unscrew all the screws, remove the glass, chip and scrape the frame back to bare metal, treat it with Phosphoric Acid (Rust converting primer/ Metalbrite HD), to prevent any future corrosion and put the glass back, the old fashioned way, with putty, because the corrosion damage would prevent a rubber seal being effective.
Any damage to the opening Port sealing faces could be similarly treated, then made good with Plastic Steel, before new rubbers were fitted.
The Chief Officer preferred to keep putting more layers of Silicon Sealant over everything, even after I pointed out that the opening Ports (especially the main Deck ones) were also Emergency Exits and it was not a good idea to have several inches of alternating layers of Silicon Sealant and paint plastered over them.

Rust is often a good way to find cracks on Deck, it acts like a slow acting Penetrant Dye Kit!

BP
It is always better to ask a stupid question than to do a stupid thing.

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JK
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Re: Picture Quiz

Postby JK » Thu Nov 25, 2010 5:14 am

The ship must send the most expendable member of the crew up to put the line over the hook, then go up to the next level and attached the rest, all while someone is taking up on the block. A recipe for disaster if the controls mess up and stick.

The below photo from one of our ships, shows the hooks hanging and not lashed to the deck fittings below. The lashings are about half the thickness of the mooring line in your pictures.
The blocks are being overhauled which is why the staging is set up.
IMG_2607.jpg
Crane blocks not lashed.
IMG_2607.jpg (54.12 KiB) Viewed 1954 times


I am sure that this arrangement on your ship would take up at least one container of bananas.

Below is the boom crutch with sides to address side loading. There is no wood on the crutch. There is a means to hook a harness when on the ladder.

IMG_2617.jpg
Boom Crutch
IMG_2617.jpg (45.41 KiB) Viewed 1954 times


I dealt with a ship that the windows had a catchall underneath with a drain that led out on deck. Good idea, right?
It was until someone plugged the drains, I suspect that the decks were being painted and the drains were dripping, or maybe the condensation from inside the accommodations was running out onto the deck and freezing.
Who knows, but someone took a short term solution that cost us a great deal of money.
Anyway, the basins overflowed, down the bulkhead and under the sub-floor for many years, until the first signs of trouble was a crunching
underfoot.
The cabins were stripped of furniture and liners and the sub-floor beat out, to reveal that the bulkhead under the windows were gone and the deck up to 3-4 feet away from the bulkhead. In some cases, that extended to the exterior deck.
We just finished another ship with the same problems in the wardroom.
Since we keep our ships so long, you have to keep on top of stuff like this. Fun and games.

Great pictures Big Pete, well worth the wait!
Last edited by JK on Thu Nov 25, 2010 11:38 am, edited 1 time in total.
Reason: Added photos


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