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Guest Bart Willems

And so it begins...

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Guest Bart Willems
The world's largest heavy lift ship is named the Dockwise Vanguard. According to insiders, plans for building the Dockwise Manfrotto are already in the making, followed by the Dockwise Gitzo, Dockwise Cartoni and Dockwise Schachtler.

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Guest Elsa Hoffmann

mmm I wonder if they forgot the world is ending Saturday. what a pity.

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Interesting story Bart.

The UK was visited last week by the largest ever moving manmade structure, apparently.

http://www.bbc.co.uk...pshire-20645300

Didn't think that was right, they must mean largest ship.

The largest moving object I think is this

http://en.wikipedia.org/wiki/Troll_A_platform

Edited by wildoat

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Guest Chris101

mmm I wonder if they forgot the world is ending Saturday. what a pity.

I thought it was ending Friday. Maybe it's going to end piecemeal.

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Guest Bart Willems

Didn't think that was right, they must mean largest ship.

The largest moving object I think is this

Actually, it would be the largest containership. Then there's "active service" (it will take a while before the now scrapped Jahre Viking will be surpassed). And it depends on what is measured. On overall length the container ships are the longest, measured on tonnage some (but not a lot) bulk carriers and oil carriers are larger, since they are wider and have a deeper draft. Container ships have a limited draft not for maritime reasons but because there's only so many containers you can stack on top of each other.

As for "moving object" I think all bets are off based on what is considered "moving", and again what the criteria are for size.

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Actually, it would be the largest containership. Then there's "active service" (it will take a while before the now scrapped Jahre Viking will be surpassed). And it depends on what is measured. On overall length the container ships are the longest, measured on tonnage some (but not a lot) bulk carriers and oil carriers are larger, since they are wider and have a deeper draft. Container ships have a limited draft not for maritime reasons but because there's only so many containers you can stack on top of each other.

As for "moving object" I think all bets are off based on what is considered "moving", and again what the criteria are for size.

Hi Bart,

Liked the joke, given some of the names ships have been saddled with over the years your suggestions are quite feasible, A couple of years ago a Hong Kong based tanker company which names all their ships Titan + name of a planet, actually named a ship Titan Uranus, it was rapidly renamed after a short period of time.

The other thing is that container ships are in fact draught limited because of some of the ports they use. Generally the absolute minimum of bottom clearance that the pilots will accept is 2 to 3 metres, and some European ports are only dredged to 18 to 20 metres at chart datum, I also seem to remember that some of the US East coast ports have the same problem.

I went down to Southampton on the morning she arrived and took some photos of her. I've put a low res one in my album but can't seem to attach it to this post.

Marco Polo

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Apologies for attaching it twice. I thought I would see it in the preview.

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Guest Bart Willems

Mebyon, you are absolutely right. What I meant, but absolutely did not write that way, was that in designing large vessels, container ships have a “natural” limitation on draught that ore carriers and oil tankers don't have. Add restrictions to beam as well (after all there's no point in building a container vessel so wide that the gantry cranes can't reach the containers on the far side of the ship) and while container ships are now among the longest ships in the world, they're still dwarfed in tonnage by large oil tankers and ore carriers.

Indeed there are draught limitations in many ports, although the ability to load/unload the vessel (large enough cranes, and large amounts of them as well) kind of takes care of that too. Ore carriers have the same problem; oil tankers don't as they rarely come to the shore in the first place.

Indeed the eastern US sea board has severe draught restrictions. The aversion against practically any government project has exacerbated that situation. That's one of the reasons the bigger locks in the Panama canal mean nothing for the US East coast when it comes to bringing in bigger vessels; the north east ports don't have deep enough water for bigger vessels (and Elizabeth=New York has the limited height under the Bayonne Bridge as additional issue), Norfolk is still working hard on extending capacity, Charleston has the depth but not the rail capacity to handle larger ships, Savannah has the rail capacity and the depth but in a brilliant decision of misplaced austerity they dredged their waterway only single lane, so at one tide all the ships can only move out and at the next tide the ships can only move into port, etc. I suspect Miami is better, but well, by then you might as well rail your containers in from LA when you need them in the New York/Boston area. Oh, I and forgot the unions of course. Good luck unloading a 14000 TEU vessel at a terminal that operates only from 9-5.

Edited by Bart Willems

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Interesting thread. I know nothing about commercial shipping vessels (but have owned recreational boats), but this container ship looks simply like an ocean going barge.

The engineering to avoid twist in that hull is challenging

I would hate to be on the broad bellied ship in rough ocean water.

Rags

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Guest Bart Willems

Interesting thread. I know nothing about commercial shipping vessels (but have owned recreational boats), but this container ship looks simply like an ocean going barge.

The engineering to avoid twist in that hull is challenging

I would hate to be on the broad bellied ship in rough ocean water.

There is indeed little finesse in the design of container vessels when it comes to looking like a pretty ship; "ocean going barge" is indeed a decent description. Main considerations are capacity, operating cost (mainly fuel) and maintenance cost. The newer designs have the wheelhouse more to the front. This allows for higher stacks of containers (as you don't need a line of sight over what's behind you) and it also allows the engine to be moved further to the back. A shorter drive shaft is cheaper, lighter and it leaves more room for containers as there's less driveshaft tunnel. Personally I'd put the wheelhouse all the way at the front (as you see with many of the Great Lake freighters) to protect the containers against the waves, but maybe it's done the other way around exactly for that reason (the deck of the ship is 5 or 6 floors above the surface but waves do go over the front in heavy storms). Despite (or because) of their size these vessels can handle amazingly rough weather although it's preferred to avoid it, as losing a stack or two of containers is not uncommon in very rough seas.

Twist is a challenge; if you search on youtube you will see videos along the bulkhead where you can see the ship twisting a couple of degrees. The ships ride remarkably well in rough water; common to contrary though the hulls are usually not really that flat. That is changing though; most container ships were built for speed (cruising speed around 20 knots; we had one class designed for doing well over 25 knots) and have V-hull to accommodate that. But that is changing; there are not enough customers willing to pay extra for speed, and "slow steaming" solves two problems at once; it lowers operating cost by reducing fuel consumption, and it helps to utilize spare capacity (adding 3 days on a transpacific voyage means you'll need another vessel to maintain a weekly schedule). The newest vessel that we're building does have a flat bottom as it's not designed to sail at high speeds (flat bottom meaning she'll ride a lot rougher) but it offers many benefits -- higher capacity, and the ability to put two engines (and screws) in the vessel instead of one.

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This clip demonstrates some of the twisting effect witnessed within the ship,

considering the stresses involved I'm amazed these ships simply don't fall apart.

[media=]

[/media] Edited by wildoat

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This clip is worth watching.

all appears well until 0.35s when the crew nearly soil themselves, lol

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This clip is worth watching.

all appears well until 0.35s when the crew nearly soil themselves, lol

[media=]

[/media]

I nearly soiled myself watching the vid... :)

Rags

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Guest Bart Willems
I nearly soiled myself watching the vid... :)

Don't join the Dutch navy!

[media=]

[/media] Edited by Bart Willems

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