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Post by WettCoast on Oct 27, 2009 19:28:14 GMT -8
The anchor on the SoBC 'spontaneously' deployed today. news.sympatico.cbc.ca/abc/Local/BC/ContentPosting?isfa=1&feedname=CBC_LOCALNEWS&date=true&newsitemid=vancouver-bc-ferry-drops-anchor-active-passCBC Local News B.C. ferry drops anchor unexpectedly: passenger 27/10/2009 11:52:43 AM -------------------------------------------------------------------------------- BC Ferries service between Victoria and Tsawwassen has reportedly been interrupted after the Spirit of British Columbia stopped abruptly when its anchor unexpectedly dropped into the water. Ferry passenger Brenda McCorquodale told CBC News the ship had just crossed Active Pass when it came to a halt. "The boat started shuddering and immediately did a very large doughnut. After about 10 minutes the captain came on and then told us that the anchor had spontaneously dropped from the boat," said McCorquedale. More to come For more see this thread: ferriesbc.proboards.com/index.cgi?board=bcferriesnews&action=display&thread=1867&page=13replies 323 through 327 'Facts' that I believe to be true: 1- The Spirits have anchors that are automatically deployed. A wheelhouse button is pushed to put them in standby mode as they enter Active Pass. The button is pushed again to take them out of standby mode as they leave the other end of Active Pass. 2 - The older V's & B's required this to be done manually. This way there was a pair of human eyes visually confirming that the anchor chains are secured after leaving Active Pass. By what means is this done on a Spirit? There is no human there. Are there cameras or some electronic device? Could this be a factor in this incident? What systems exist on other vessels? I assume the C class are also manual like the V/B's? What about the Coastals? By starting this thread I am intending that we have a general discussion on ferry anchors, including how they do things on our neighbours fleets in Washington & Alaska. Also, while I am here, the SoBC is currently being operated by SWB based crews, who normally operate her sister the SoVI. Are there important differences in these vessels, particularly with respect to how the anchors are placed in standby & deployed? Might this have something to do with today's incident? The manual method - QoNWM - April 2009 [JST photo ©]
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Post by Scott on Oct 27, 2009 20:49:09 GMT -8
By what means is this done on a Spirit? There is no human there. Are there cameras or some electronic device? Could this be a factor in this incident? What systems exist on other vessels? I assume the C class are also manual like the V/B's? What about the Coastals? Most (if not all) the times I have been on a Spirit vessel, there has been a deckhand at standby near the anchoring equipment, as pictured above, during the transit of Active Pass. Whether he/she is there just as a watch, I am not sure.
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Nick
Voyager
Chief Engineer - Queen of Richmond
Posts: 2,078
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Post by Nick on Oct 27, 2009 21:01:12 GMT -8
Here's what I understand to be the situation around the anchor control methods of the Spirits.
There are 2 hydraulic "arms" (I'm not familiar with the actual term for these things, so that's what I'm calling them) that are normally across a link on each anchor chain that prevents them from being inadvertently dropped. The anchor chain is wrapped around a capstan, which is controlled by an electric (or hydraulic?) motor with a brake. The arms are there in case the capstan brake fails. As I understand it, the anchor capstans can be controlled both locally at the fo'csle, or from the bridge.
During transit of Active Pass, the arms are lifted from a bridge control so that the anchors can be dropped at a moment's notice. In the old days this was done manually by a deckhand. There IS a deckhand stationed on the fo'csle on a Spirit to serve both as a lookout and to drop anchor in an emergency.
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Mill Bay
Voyager
Long Suffering Bosun
Posts: 2,886
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Post by Mill Bay on Oct 27, 2009 21:09:09 GMT -8
Well, this is a pic I took of one of the capstans while transiting Active Pass... the arm that locks the anchor chain down is in the raised position. It's the metal arm with the red reflective tape on it... I do not recall seeing a lookout on this particular day, or ever, on a Spirit for that matter. You can see the change when the arm is locked down... it would be better to have pictures from the upper deck, though.
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Quatchi
Voyager
Engineering Officer - CCG
Posts: 930
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Post by Quatchi on Oct 27, 2009 21:13:33 GMT -8
The anchor locks (arms) as Nick has noted are clearly visible from the deck 6 outer passenger deck, so I am assuming that the bridge crew could see them if they took a walk over to the window. As far as I have noticed the units are the exact same on both spirits.
I recall a deckhand running down to the focsle through the stairway from the deck 6 passenger deck and down the little ladder every time Ive been through active pass.
Cheers,
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Post by Ferryman on Oct 27, 2009 21:15:23 GMT -8
When the ships transit Active Pass, the Choke is released so the anchor can be dropped in a hurry if needed. To drop the anchor, all you do is turn the brake handle, and let gravity do its thing to drop it. To bring it back up, you turn on the electrive motor that reals the chain back in with the gypsy. For more info on a windlass, check out: www.answers.com/topic/anchor-windlassDiagram wpcontent.answers.com/wikipedia/en/8/8c/Ship_anchor_windlass_diagram.gifPS: I'm almost fairly certain that the ferries aren't equipped with a Devils claw, which also helps stop the chain from dropping. You can see where it would be located in the diagram above.
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Kam
Voyager
Posts: 926
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Post by Kam on Oct 27, 2009 21:35:17 GMT -8
The coastals have a similar arrangement. In this picture you can see the hydraulic ram that pulls the locking arm out of the way. The grey wire the runs behind the arm is connected to a sensor that indicates the arm position on the bridge control panel. This compartment is also monitored by cameras. Full resolution: www.flickr.com/photos/kams_world/4030701271/sizes/o/in/set-72157614959208012/
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Post by uricanejack on Oct 28, 2009 0:44:58 GMT -8
Exactly what happened will not be known until after an investigation is completed.
There are a couple of different anchor systems used by large ships. Most are very similar.
Either a winch and windlass arrangement which is laid with a horizontal drive most deep sea ships.
Or like the ferries most have Capstans which have a vertical drive.
At one end there is an Admiralty Patten stockless anchor size varies with size of ship.
The anchor is shackled to the anchor cable by a large D shackle.
The Anchor Cable is the length of chain. Which is in 90 foot lengths known as Shackles due to the Kenter joining shackles which connect the 90 foot lengths?
A kenter joining shackle is shaped like a chain link is usually painted red or black with the links adjacent painted white in sequence to the No of Shackles from the anchor.
I.e. 1 shackles 1 whit link. Also wire wrapped round stud in the link for when paint wears off.
The chain goes up through the haws pipe (from anchor to deck) over or round the Gypsy (shaped wheel links fit into) and down the spurling pipe to the chain locker.
The Chain is stowed in a heap most but not all are self stowing.
The Bitter end is secured in the chain locker there are a No of different types of securing arrangement. Some have a slip pin just inside locker door or cover. Others are secured to a weak link in bottom of locker.
The V Class ferries have 10 or 11 shackles of cable the spirit class a couple more
13 x 90 = 1170 ft of cable.
Cables are also a nautical term for distance = to 1/10 of a Nautical mile aprox 600 ft actually 185.2m
Crash stop distance from full speed for ferry aprox 0.5 KN miles. Or 5 cables. If everything goes right.
Ships Anchors are generally secured with a brake similar to a drum brake only on outside of drum. The Gypsy is the drum. Tighten by wheel and screw.
The anchor is raised by a winch which can be put into gear with the gypsy to raise the anchor or lower slowly.
The anchor windlass is never left in gear. The Anchor could not be dropped if in gear and can not be taken out of gear if there is any weight on the gear.
The anchor is not left just on the brake except when ready for immediate use or stand by. E.g. For arrival departure or transiting narrow channel like Active Pass
Some one is always supposed to be standing by the Anchor when “ready”.
On passage there is always a second means of securing anchor in case brake vibrates or gradually slackens loose.
A Devils Claw is one kind of method involving a claw shaped hook and bottle screw.
Sometimes just securing chain through anchor cable.
Some times a Compressor Barr goes across and between cable links (smaller ferries use)
The V Class use compressor which is manually screwed down onto the cable clamping it into place.
On the Spirit class the compressor and the brake can be operated remotely from bridge.
If the Anchor is ready and needs to be used in an emergency to stop the ship. Or to assist in docking in bad weather.
The procedure is to drop the anchor when ordered to the bottom then secure and hold at preset length in active pass 2 shackles or 180 ft of cable. On deck. 1 Shackle or 90 ft for docking.
The Anchor is then dragged along the bottom slowing the ship gradually.
If an Anchor is let go unintentionally at full speed.
It will probably not drag. The brake is not designed to stop the ship. This could really ruin your day.
They are very fortunate the ships speed was reduced enough so the cable didn’t part when it reached the “Bitter End”. And nobody was injured or killed.
The brake lining and the Captains short’s probably both need replacing.
What happened?
Something or someone screwed up. Someone acted very quickly to avoid a disaster.
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Post by Northern Exploration on Oct 28, 2009 7:04:50 GMT -8
The story made the national papers today. Was a short blurb but nevertheless made the news.
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