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Anchored cruise ships are having anchor problems

Stemar

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12 Sep 2001
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Home - Southampton, Boat - Gosport
Obvious, innit. Their mistake is using all chain rode. You get a blow, the catenary straightens out and you've got shock loads. As JD says, they should be using snubbers or a few metres of chain plus a goodly lump of octoplait.

I am available for consultation to Cunard and others at a special rate of £1500 per hour.
 

eddystone

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SW Leicestershire
Interesting that cruise ship anchors only expected to hold to 48 knots and then only in flat water - if wave height over 2M, then only 21 knots. Most cruising sailors would I think expect more of their anchors than that. Clearly their anchoring technique relies on a) continuous watch b) enough crew to take necessary actions in case of drag, c) have at least one engine running at all times
 

AntarcticPilot

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I've often seen ships at anchor in the Clyde. It can be difficult to even see their chain from any distance, and I've often wondered how such flimsy (in proportion to their size) gear can possibly hold against any substantial load. Just by way of comparison, if I use 6mm chain, the width of a link is 45mm. My boat is about 9350mm long, so the ratio of chain size to length is about 1:200. For a 200m ship, that would mean the corresponding chain ought to be over a metre across, with a wire diameter of around 150mm!

Obviously, I'm ignoring scale effects! But surely the chain ought to be much larger than the stuff a few inches - less than a foot - across that they do use.
 

LONG_KEELER

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East Coast
It appears that metal anchors for ships are going to be a thing of the past.

Probably due to global warming , salinity changes are showing that although metal anchors look okay, the cellular integrity is breaking down at alarming rates.

So far, granite anchors are showing favourably in tests and look like being the anchors of
choice.
 

dom

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Genuine Q: I thought some climbing rope is stretchy, so actually very good for snubbers?

To which I can genuinely say it makes fantastic snubber material on yachts, especially good when it’s either bouncy or the boat tends to yaw.

Such snubbers are also good for personal well-being in that they dramatically reduce those jarring snatches that have you sitting up in bed thinking WTF 😳

Naturally, they’re unsuitable for those who measure their anchor chain in shots 🙃
 

Capt Popeye

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Dawlish South Devon
As I understood it, following an On Board Cruise talk by a Engineer Officer; the Cruise Ships have maximum operational Sea conditions, maximum operational Wind velocities, maximum operational Wave heights, which the Captain must keep within for a safe operational cruise ship.

Thge Cruise Ships Head Office keeps a watch on all weather forcasts, which for them, includes all the parameters refered to above; the HO can instruct /advise the Ships Captain to change course or to take necessary actions to place the Ship in safer waters or shelter from Storms; or cancel the Cruise and return into a Port untill the severe weather passes;

I was supprised at what I thought to be a fairly minor Storm to be the Max Designed Storm for a Ship; the stablisers also have a max designed storm /wave height / wind strength which they can operate in.

Might seem to be very large them Cruise Ships and therefore robust and safe, but they obviouly have a fairly low operating level; not supprising I guess when one compares the sheer height of them !
 

AntarcticPilot

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As I understood it, following an On Board Cruise talk by a Engineer Officer; the Cruise Ships have maximum operational Sea conditions, maximum operational Wind velocities, maximum operational Wave heights, which the Captain must keep within for a safe operational cruise ship.

Thge Cruise Ships Head Office keeps a watch on all weather forcasts, which for them, includes all the parameters refered to above; the HO can instruct /advise the Ships Captain to change course or to take necessary actions to place the Ship in safer waters or shelter from Storms; or cancel the Cruise and return into a Port untill the severe weather passes;

I was supprised at what I thought to be a fairly minor Storm to be the Max Designed Storm for a Ship; the stablisers also have a max designed storm /wave height / wind strength which they can operate in.

Might seem to be very large them Cruise Ships and therefore robust and safe, but they obviouly have a fairly low operating level; not supprising I guess when one compares the sheer height of them !
On a thread about the Evergreen Given, someone pointed out that a scale model of a ship like that would be made of something like kitchen foil. Our yachts are far stronger in relation to their size than any ship is. Think about it - ours have hulls several cm thick over lengths of 10-15 metres long. We have bulkheads at about 2-3 metre intervals. Compare that with a ship. Hull material a bit thicker, but comparable. Material strength at most twice that of fibreglass, and probably less than modern carbon reinforced plastic. Length 100+ metre. Bulkheads spaced further apart than the length of our vessels - perhaps twice the length of a container.

Put like that, it's a miracle of engineering that they are seaworthy at all! But it's not at all surprising that they have lower limits for storms than we do. I don't want to be out in a hurricane, but I reckon Capricious could take it - I might not, though! But a ship had better avoid such conditions.
 

Neeves

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Sydney, Australia.
The answer to many of the comments is contained in Concerto's original link, final paragraph

quote

The International Association of Classification Societies (IACS) advises that the anchoring equipment is not designed to hold a ship off fully exposed coasts in rough weather, or to stop a ship that is moving or drifting. In these conditions the loads on the anchoring equipment increase to such a degree that its components may be damaged or fail due to the high energy forces generated, particularly with ships with high windage.

unquote

Cruise ships, or any large commercial ships were never ever planned to anchor for long periods of time, they were designed to be at sea, basically continuously. A ship that is not at sea, or loading/unloading, is not earning its keep. Similarly ships at anchor are not earning their keep - and the ground tackle is not the safety feature that ours might be. The Classification Societies make this very clear - ground tackle is there to allow a ship opportunity to anchor before entering port. On the Australia east coast bulk carries queue at anchor off Newcastle to load coal, if the wind is forecast to be over 25/30 knots (I'm sure exactly but not 'very' strong) the ships are ordered of the anchorage and it is demanded they steam up and down until the winds ease (they have had one too many on the nearby beaches).

If a large commercial vessel is at anchor in strong wind they will commonly motor to reduce the forces on the ground tackle (and ship itself).

As Popeye mention the Captain is ostensibly in charge but modern fleets are controlled centrally and if bad weather is forecast the Captain (presumably in consultation with the head office) decides what action might be taken to minimise the effects of weather. This is particularly true of cruise ships whose 'cargo' is on holiday and will remember for the wrong reasons if subject to a Force 11 storm and 11m seas.

Jonathan
 

capnsensible

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Some may find this report of interest. Bit long, mind.

https://www.mitma.gob.es/recursos_mfom/fedra.pdf

It concerns the grounding and subsequent loss of MV Fedra that occurred during high winds whilst anchored off Gibraltar. Some of my yacht crew at the time met the Spanish helicopter pilot in an hotel bar. As one does. He told them that he saw gusts of 100knots......

It highlights the master v owner dilemmas.
 

Stemar

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12 Sep 2001
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Home - Southampton, Boat - Gosport
the anchoring equipment is not designed to hold a ship off fully exposed coasts in rough weather, or to stop a ship that is moving or drifting. In these conditions the loads on the anchoring equipment increase to such a degree that its components may be damaged or fail due to the high energy forces generated, particularly with ships with high windage.
Maybe I'm looking at this from a yottie PoV, but I would have thought that "off fully exposed coasts in rough weather, or to stop a ship that is moving or drifting" is exactly when a cargo ship is most likely to need its anchors to do their stuff, as bad weather is when engines are most likely to fail, and if the ship can only be stopped or kept from drifting with the anchors, the engines have already failed. I get the idea that the ship is insured, so disposable in extremis, but to take the same attitude to the crew leaves a little to be desired in the ethics department.

Or is that that the huge momentum of a panamax+ is so great that, even at a knot or two, no anchor or chain will do the job?
 
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