Model Boat Mayhem
Mess Deck: General Section => Full Scale Ships => Topic started by: Brian60 on November 23, 2015, 07:04:25 pm
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It get hairy from about a minute in, I just love the flames, then the crew looking for cover
https://www.facebook.com/scheepvaartinbeeld/videos/804960746292385/
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It's not fun when the brakes overheat and catch fire. Lucky only happened once on me (Astern RAS in the North Sea in roughens )and the big gofer we took over the front end sorted that out
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Great old classic; How Not to Drop Anchor (or Lookout Below);
https://www.youtube.com/watch?v=y3WveEZykJ8 (https://www.youtube.com/watch?v=y3WveEZykJ8)
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So what made the brakes fail in the first place or was it novice brakeman error? I take it the end of the chain had to be salvaged and rethreaded through the hawse? I wonder how much that costs {:-{
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I vote 'operator error'. At one point, the chain has been stopped, and does not commence running out when the operator loosens the brake. Then we see the brake operator taking LOTS of turns off the brake - BIG MISTAKE. Then the 'fun' begins in earnest, and the operator can't tighten the brake fast enough to keep the chain under control. Once the chain gathers enough momentum, the brake cannot stop it, and there's nothing left but to get everybody out of harm's way.
Was there some sort of 'emergency brake' on the structure the chain runs through, just before the chain passes into them hawsepipe?
Tom
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Good point Tom, I was looking at it from time to time expecting it to clamp shut, but maybe it is just a frame for a guide wheel?
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The vessel may not be that old, however the drum wheels are usually a high grade steel for mechanical strength over earlier iron wheels
When anchors are hoved in, the chain is blocked at the hawser mouth, and in addition, the brake band engaged in compression over the drum
With all things being equal [hoved in anchor] the sections on the diameter of the drum not covered by the brake bands are the same each time and subject to corrosion
This corrosion literally causes the diameter of the drum to be egg shaped causing higher friction as the corroded surfaces rotate under the brake bands......this results as seen by the jerkey motion as the anchor commences its fall
This semi stop start jerky motion can cause inexperienced seaman to release brake tension off the drum...which ultimately causes the increasing overspeed that the brake is not capable of restraining
The culprit?...inexperienced Deck Officer procedures in not ensuring regular or periodic maintenance is not carried out on windlass systems?
There is a good video of an American aircraft carrier having difficulty in releasing an anchor.......bit scary >>:-(
https://www.google.com.au/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&ved=0ahUKEwjniPm30KfJAhWkraYKHbcRCVIQtwIIIjAB&url=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DLg3wwhhJ1aM&usg=AFQjCNEAxw4zcR11tcPwSKiLa8mqwQJsbg
30 years ago, a 'single anchor and chain' on an BHP Fleet Operations 100,000 tonner was just on 1/2 a Million AUD$.......... Derek
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Cheaper to salvage then!
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When I was at sea, this would have been put down to inexperience/ bad seamanship, should always walk down heavy anchors ans chain with the windlass in gear. The result you saw there was a wrecked anchor windlass and a loss off some cable and a anchor. If I was the master I think I could be getting ready to face a MCA / MAIB official enquiry and my ticket could be on the line.
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Now I know nothing about ships but I was led to believe that the anchor chain was fixed at one end to the chain storage bin?? I thought this was called the "Bitter End" so if this is true why did the chain simply run until it was depleted?? Or of course I'm now in for some serious ribbing - let the ribbing commence {-)
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I've heard that modern ships have the anchor chain designed to break free - nothing is going to hold it, in the situation in the video. Replacing the chain is cheaper than replacing all the interior structure.
Time for the experts to chime in! - Tom
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Heres a picky of what I meant???
(http://i802.photobucket.com/albums/yy307/m4rky-photos/14325_180_1_zpsm4ayehbq.jpg) (http://s802.photobucket.com/user/m4rky-photos/media/14325_180_1_zpsm4ayehbq.jpg.html)
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Now I know nothing about ships but I was led to believe that the anchor chain was fixed at one end to the chain storage bin?? I thought this was called the "Bitter End" so if this is true why did the chain simply run until it was depleted?? Or of course I'm now in for some serious ribbing - let the ribbing commence {-)
This subject has already been done to death elsewhere on the Forum but, at the risk of repeating myself, there is indeed a 'bitter end' in the chain locker (not "storage bin") to which the end of the anchor chain is attached. However, no matter how strong the bitter end and the plating to which it is attached may be, the effect of tons of chain running out uncontrolled and at high speed will be to cause severe damage to the bitter end, the chain locker and the surrounding structure if the chain is shackled directly to the bitter end. (Note that I am talking 'big ship' arrangements here; small craft may well be arranged differently.) Thus, it is common practice to introduce a weak-link between chain and bitter end. This will be strong enough to locate the end of the chain and prevent it from getting tangled up but weak enough to part if the chain does a runner. The weak link will typically be a wire strop.
BM
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What Barry said! :-))
Can you imagine what would happen to the bulkhead and surrounding structure without a weak link? The whole lot would be following the anchor and chain down to the seabed!
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Especially if it bursts the outer hull to get out!
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The cost of a work boat & diver is relatively inexpensive compared to anything else.........the heaving rope is fed over the chain drum, around a bollard & then wound in on a jipsy drum....that way the chain will automatically bed in & engage the chain drum
The weight of chain just from the hawser to the chain drum would be considerable & difficult to man handle....... Derek
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The chain would probably break before the bitter end shackle, as chain cable is very susceptible to parting when shock loading. That's why there is always considerable attention to anchoring a commercial vessel and the chief officer should be in charge of the anchor party. In my career I have partied twice the anchor cable, once when we fouled a wreck and overloaded the chain on recovering the anchor, the other time was north of Anglesey when the boatswain let go off the anchor by accident when the vessel was doing about 11 knots. The last I lost my anchor which was about 7cwt, my manager wanted me disciplined over the matter as I was the master. I had to go into port for the windlass to be surveyed by Lloyds and get a dispensation letter from them to sail why a new anchor was located for the vessel, lost 4 days work time. In the video clip you can see the cable break on the gypsy, could have picked up a clump of cable which jammed under the hawse pipe in the cable locker, another problem when paying out chain, if it is not used a lot it rusts welds into clumps.
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Correction to last I think the Arrochar had 1.5+ ton anchors.