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Electromagnetic Ship Docking System Debuts
Makarand writes "A system that uses electromagnets for docking ships is getting ready to be tested at a port in the
Netherlands according to this
article in the New Scientist. Magnetic docking systems were never used in the past as magnetic fields
posed dangers to sensitive cargo like TVs and monitors. Researchers at the
Delft University of Technology have developed electromagnets whose magnetic fields do not
penetrate far into the ship for this special application.
The magnets can be periodically switched off and on rapidly to allow ships
to rise and fall with the tide."
Electromagnetic ship docking systems are very attractive.
I wonder if the points where they plan to mount all of the electromagnets are going to up to the job... it doesn't seem like they would have been designed for stress in that direction.
If they can make this work, then it sounds great - I'd be concerned about the risk to the ship's own electronics, though, as much as to its' cargo. Computerised navigation systems, and the like, and ship-wide systems whose wiring well run very near, or even along the inside of the hull... Neat idea, and one that may well send the internationnal rope-manufacturing industry into decline - after all, who else needs four inch diameter hemp ropes in this day and age...?
I can imagine this tech being great for mid-air and outer space docking situations? is this kind of technology in place for such applications already?
my pet machine
Seriously, in the U.S. we just recently had a paralytic dockworkers' strike. I don't think they'd be amused by this labor-saving innovation. Not that I think people should be kicked out of jobs by robots.
Each of their mooring magnets generates a 1-tesla magnetic field. (from NS article)
WOW! That's strong. I used to work with a 1.5-T superconductor magnet, an MRI scanner, and it had a heck of a pull. Enough so that people have been injured or killed when a piece of metal got loose. It took three of us to pull off the base of an IV pole (no one inside at the time). Some of the research magnets are 4-T or more. But these are all superconductors, and act like permanent magnets. The resisitive magnets here must produce tons of heat while gobbling electricity. Surely "auto-dock" wouldn't be too hard to design., with mechanical restraints?
So, at work, I work with a 1.5 Tesla magnet (Gyroscan Intera... used for nuclear magnetic resonance imaging; VMS/VAX/Solaris Operating Systems). Price tag on the thing is about $1M, which makes me wonder:
1) Did this docking system actually cost only $50M? At $5M a year, is a 10 year return on investment reasonable?
2) Is it actually Helium/Nitrogen cooled? We have to have a dedicated coolant system for our magnet to work at 1.5 Tesla. Moreover, what happens if a magnet breaks? They're not going to vent 2,000L of Helium, per magnet into the ozone, are they? (52 magnets = 100,000L total of liquid Helium)
2. Invent electromagnetic ship docking system 3. Call it a tractor beam! 4. Profit!!!!
Methods of Securing Ships:
:)
Lots of Ropes:[Initial Cost: £10,000, Ongoing Cost: £0 (near enough)].
Electromagnets:[Initial Costs £50,000, Ongoing Cost: £1000s/month]
I think the problem is obvious here
Arc
From the article:
"Mooring a ship can be a time-consuming, labour-intensive affair in which dock workers grab ropes hurled from the deck of the incoming ship and secure them to the dockside."
I've never been one decry progress because it'll put some people out of work, but this does have the potential to unemploy a whole crapload of people over the not-so-long term.
I wonder how the dockworkers union is handling this?
My
Limekiller
What do you do in the case of an extended power failure? I know they probably have diesel backups, but even those only last so long.
At least living in the Bay Area with all the uproar about the "Energy Crisis" a couple of years ago, this may not be the most reliable system if you had to rely totally on electricity to dock all those boats up there in Oakland....
Mostly, the chain and combo lock doesn't address the issues which electromagnetic mooring systems do. There are a lot of factors involved with a project like this, including sway, roll, and yaw of the boat, which chains and locks don't handle. The chain and lock system acts like a yo-yo or a swing, in so far as two objects are attached together by a string. The electromagnetic mooring system acts like, well, a refridgerator magnet does to a refridgerator.
I've spent several years working as a dockhand for large yachts (100-200 feet). While these boats arn't as big as the tankers and cargo ships which will utilize the magnet system, the manuvering and handleing is similar. Dock lines are not just used to hold the ship once it is in position to the dock - they are also used to manuver the vessle as it is docking (for example, a line will be thrown from the front of the ship, made secure, and the ship will power against it to bring the back of the ship into the dock). Obviously, the magnets wouldn't work at this range (50+ feet)
Methinks docking lines might be a bit cheaper too - and when properly set, only slight adjustments need to be made for the tide.
What would be very cool to see is the magnet start attracting someone's belt loop or a leatherman out of someone's pocket standing nearby... wow
You've never going to save 40 minutes.
This is just a solution looking for a problem, and I'll predict that it'll never ever be used.
I live at a port in New Zealand (just outside Christchurch actually) and often watch the ships docking. My father used to tie them up. If I look to my left, I can see about a half-dozen ships out my window.
The majority of the 40 minutes that the article quotes, that it takes to berth the ship, is the tugs turning, and pushing the ship to the wharf. That's the thing with ships, they have a big propeller at the back, which pushes them forwards, and they can't move from side to side. They do have a rudder, but it's not designed for more than a few degrees of turning, you can't use it to dock. (I'll stay away from bow thrusters for now)
Basically the process goes like this...
A Pilot (who works for the port, and is an expert in the local navigation/conditions of the port) is taken to the ship on a small launch, and meets it several miles from the harbour.
The Pilot then commands the vessel, until it's tied up at the wharf. (s)he co-ordinates the ship, tugs, and wharf staff who, at the end of the operation drop the ropes over the bollards.
Securing the ship with the ropes takes about 5 minutes on a slow day, getting the ship alongside the wharf takes about 35 minutes. The thing with ropes is, that...
1) They're proven. They've been using them for thousands of years.
2) It's a standard system, used all over the world.
3) It's simple, never underestimate this.
4) it copes well with varing weather and tides.
5) You still need ropes to tie between the tugs and the ship.
Now, as I said before, you've going to save about 5 minutes per berthing? Your damage costs are going to far outweigh the costs of any savings.
And, what happens when the power goes out?
The ship floats away, probably onto rocks.
Backup Generators? Yeah sure, a diesel generator is going to hold a ship with 4-8000 shipping containers alongside a wharf, is bad weather, and an especially high tide, with no outages.
I'm sorry, but there's no way this would ever work.
While the magnetic field would be bad for general cargo, something like oil wouldn't, so this could be used quite easily at an oil terminal.
Although I can't find any technical details from Google, the Alsterdampfer in Hamburg, Germany, have been using a magnetic system for at least 30 years (no snide comments about my age, please). In this image, you can see the magnets as the black-faced buckles on the side, just above the waterline.
For this to work, the side of the jetty is plated with steel plates for the magnets to hold on to; depending on the skill (or inclination ;-) of the captain, the boat can be tucked towards the jetty quite violently...
I'd worry about permanently magnetizing the hull.
Sure, there won't be enough residual that it sticks to other passing ships, or anything, but what about interference with magnetic compasses.
I had a steel-tube frame airplane, and it got so magnetized from arc welding that the mag compass was totally useless. No amount of swinging could correct the compass deviation. Nor did it help to replace the mag compass with a new one. I ended up degaussing the whole fuselage with a degauss coil designed for TV sets, and never had the problem again.
But I can't see doing that on the scale of a container ship!
5,000,000 Euros = 5,335,000 USD
Storm force 12 = 80 knots = 92 MPH
The Navy tried this using the USS Philadelphia, but the field was too strong, and the ship disappeared. It came back later filled with drunken Eagles fans.
If Slashdot were chemistry it would look like this:Cadaverine
Navies spend a lot of time and money making sure that their ships have small magnetic signatures -- magnetic triggers are common in undersea mines. Somehow slapping a few big magnets on the side of a ship everytime it docks doesn't seem like a good idea.
First of all, this is an experiment. Experiments never usually make money in the short term.
Secondly, here's a quote from the article (which several posters need to actually read):Could we please concede the possibility that someone has done a marginal amount of research into this and backed these figures up on some real numbers? Maybe it won't save them that much, or maybe the whole thing will end up costing too much. That's the point of an experiment, after all: to determine if something is going to work.
And for all of the couch port authorities inhabiting Slashdot, please remember that this is probably going to be done with the blessing (and financial support) of a large ocean port. I know that perhaps many of you think you know more about docking ships, managing large ocean-going vessels and the expenses associated with these activities than those in charge of these ports, but please take a deep breath, relax for a minute, and consider the possibility that maybe they're supporting this experiment for a reason, and that reason probably has less to do with a mad scientist trying to dupe someone into buying them a lot of expensive magnets and more to do with a convincing argument that this experiment could save them money in the long run.
Yup, I did read it, but one of my unvoiced concerns is that a 1 Tesla field is only the final steady state value. When you pulse current into an inductor or turn off current, in any real-world system it is not a pure inductance, and often ringing occurs. When that happens, the instantaneous values of the (presumably damped though ringing) current could hit higher peaks. I don't know what pulse levels may occur, what EMI induced effects may occur, etc. The external docking electromagnets could induce currents in the hull that couple inward.
>push orange button
The writing on the button changes as you press it
The Royal Barge drifts slowly around the bend, ending up near the western bank of the canal.
>read orange button
The huge orange button reads: MagnetoMoor off
>_
(From 'Leather Goddesses of Phobos' Infocom, 1986)
Calling Rotterdam just "a port in the Netherlands" is an understatement: Rotterdam is the largest port in the world and has been for some years...
I hope the pilot remembers to attend the academy lecture on conservation of tractor beam power!
You know, those abbaci worked real well for centuries, too...why oh why did we ever think about replacing them?
-- Waht? Tehr's a preveiw buottn?
... of an accident. I've been in the Navy for 20 years. Ship's hit hard sometimes, even with tugs, when the current, wind, etc. go against you. Right now it's a bit of wood that gets crunched. What's the cost on those magnets again? And as if water, salt, air and metal weren't bad enough, toss in some high current lines and huge magnetic fields. Seems very complicated, high maintenance, and for no obvious benefit.
"Consensus" in science is _always_ a political construct.