I’m on all sorts of news mailing lists here at BMEWS, to try to stay on top of the many things going on around us. Sometimes I get mail with a subject line that makes almost no sense. This one is an example. I read it and said “What on earth? Or maybe not on earth at all?” It sounds like some kind of futuristic genetic modeling attempt by NASA to populate one of the Jovian moons, right? Like the ones that are all water, with just ice at the surface? How far has this cloning and genetic stuff progressed when I wasn’t looking?
Wrong. Nope, that’s not it at all. This is one of those technology posts, and there are no pictures of pretty girls in it anywhere. So only peak below the fold if you’re interested. I’m interested, because, hey, how often do you ever hear about mermaid pods? What the heck are mermaid pods anyway?
Converteam of France has announced that Mermaid podded electric propulsion, developed by Converteam and Rolls-Royce, has been ordered by STX Europe for Hapag-Lloyd’s new ‘Europa 2’ cruise ship. The ship, being built at Saint-Nazaire, France, for 2013 delivery, will be fitted with two Mermaid pods with 7.25MW synchronous motors, fed by PWM MV7000 converters.
...
Loïc Leclere, marine technical director of Converteam, said: “Converteam’s PWM MV7000 drives using the press-pack IGBT technology have allowed a new step forward in pod propulsion.This new Mermaid order, which follows the one for the French Navy Dixmude LHD, confirms Converteam and Rolls-Royce joint leadership in pod systems with sustained focus on efficiency and availability”.
artist’s rendering of the new Europa 2, currently under construction
The
Europa 2 is an ocean liner on the drawing board. The construction - what the ship guys call a “newbuild” - will begin in September. What with all the pirates and the ship hijackings, I’m on several maritime mailing lists.
EUROPA 2 is the contemporary and informal interpretation of a luxury ship with 5-star standard. From 2013 onwards the new ship will be setting sail for Hapag-Lloyd Cruises. The STX shipyard in French St. Nazaire has been commissioned with her building. The 20-month building period begins in September 2011.
For the first time ever, a second ship will be positioned in the luxury segment of the Hapag-Lloyd Cruises fleet. The EUROPA 2 will offer a modern and casual 5-star alternative to the existing EUROPA. The commisioning will be in spring 2013.
In a move that is unprecedented in the luxury segment of its fleet, Hapag-Lloyd Cruises is launching a second ship carrying the same name. Alongside the existing EUROPA, the EUROPA 2 will be positioned as a lifestyle-oriented and informal alternative on a 5-star level. Modern entertainment will replace the type of entertainment traditionally associated with cruises. The contemporary, luxurious design and the informal atmosphere with international flair will convey a feeling of relaxed elegance.
The EUROPA 2 with her eleven decks and 258 suites will accommodate a maximum of 516 passengers and offers the largest amount of space per passenger on a cruise ship.
It’s a great concept, especially for anyone who has gone on one of those modern cruises, where the ship is the size of a town, has several thousand passengers, and your expensive room is half the size of a standard shoebox. Europa 2 will be a smaller ship, 39,500 tons and 225m long, compared to the 100,000+ tonnage 300m length of the mega-liners, and oriented so that each couple has a small suite of at least 28 square meters. That may not sound like a whole lot of living space, but it’s actually about 302 square feet; a cabin room 15 x 20 feet. That’s enormous when you consider that many of the cabins on even modern cruise ships can be as little as 160 square feet; 300 sq ft is 15% bigger than “family staterooms” that can accommodate up to 6 people. Shoehorn!!
Obviously sailing on the Europa 2 will not be for the riff-raff. It’s going to be pricey, but it will feel refined, relaxed, private and unhurried. And that’s what a vacation should be, yes? Let’s see how long it lasts until they lose money, rip out all the suites, and install 1100 shoebox size anti-Tardis cabins (those that are larger on the outside than on the inside!)
So, where’s the mermaids? And their pods?
Mermaid pods is the name of the latest propulsion solution. Unlike a regular ship, which has and engine or a boiler powered turbine that turns a giant driveshaft that turns an equally giant propeller, all of which vibrate the entire ship constantly, mermaid pods are massive electric motors hooked directly to the propellers themselves. They hang below the ship, looking like streamlined teardrops mounted on stalks with props attached. The pods come in two varieties: the ones that are firmly mounted - fixed in place - are called fixipods, and the ones that can turn through 360° of azimuth are called azipods.
3 mermaid pods on Voyage of the Seas
Voyage of the Seas is driven by 3 mermaid pods. The two on the outside can spin about, so they are azipods. The one in the center is attached to the back of the skeg and doesn’t turn, so it’s a fixipod.
4 mermaid pods on Queen Mary 2
Mermaid pods on the Queen Mary 2. The two forward are fixipods, the two stern ones closest to the camera are azipods. The vertical thing in the middle is the skeg.
Queen Elizabeth II left, Queen Mary 2 right. That’s one damn big boat!
The Queen Mary 2 is an immense ship, more than 139,000 tonnes and more than 1139 feet long. The four mermaid pods can drive her to nearly 30 knots. Azimuth pods also eliminate the need for rudders, which simplifies design and reduces underwater drag. They also provide enormous amounts of thrust; the motors are rated in terms of megawatts. Huge! Azipods allow the QM2 to turn completely around within her own length and to dock without using tugboats. Combined with bow thrusters, the pods provide enough power to drive the ship sideways, or to hold it in place even in a 35 knot (40mph) wind.
pods also power Carnival’s ship Millenium:
Each of the pod propulsors is rated at 19.5 MW and swings a 5.75 m diameter fixed pitch propeller. The propeller acts as a tractor unit located in front of the pod. This ensures an optimum undisturbed water inflow to the propeller, thereby decreasing vibration and noise and also increasing propulsion efficiency.
The electric drive is provided by the latest synchroconverter drive technology supplied by Alstom, which gives the Mermaid system stepless control of propeller speed and hence propeller thrust to provide seamless ship propulsion.
The pod can be rotated through 360 degrees to provide the required thrust in any direction. This eliminates the requirement for stern tunnel thrusters and ensures that these latest generation vessels can maneuver into the smallest of ports without the need for tug assistance. A further benefit is the ability to reduce propeller pressure pulses and propeller-induced noise using the tractor pod concept. Pressure pulses can be the main source of propeller-induced vibrations; by using the Mermaid thruster, passenger comfort is considerably enhanced.
I wonder if the ship is also quieter on sonar?
Interestingly, these pods are primarily air cooled. Should the motors catch on fire, they just close the vents and the fire goes out. The cold ocean takes care of any other excess heat. Electrically driven pods are the most efficient means of large ship propulsion right now when you need variable speed. The generators can be located anywhere, which makes the design easier. Eliminating the rudders simplifies things as well. They also use fixed pitch propellers. All in all, mermaid pods are a great idea that saves loads of money, improves fuel efficiency, and gives you a ship with amazing handling. A perfect system? No, not quite yet. There have been a few teething problems, and a few related lawsuits. But it seems like the concept is pretty well settled. The French Navy has ordered several new ships to be built with them.
Lots of technical details et cetera, and more pictures of pods and stuff:
http://dvo.free.fr/systemsarticles.htm
http://www.shipsnostalgia.com/guides/Carnival_Corporation_History_-_Part_3
http://sections.asme.org/Fairfield/FEBRUARY%2023,%202005%20FAIRFIELD,%20DOLAN%20SCHOOL%20OF%20BUSINESS.htm
http://www.cruiselawnews.com/tags/pod-propulsion/
http://www.marinelog.com/DOCS/PRINT/mmipods2.html
http://www.7blueseas.com/cruiselines/ship.asp?id=49&page=7
Oh, last point. I am not 100% sure whether “mermaid pods” is a generic name, or a trademarked term owned by Rolls-Royce. If the latter, then sorry RR, but I intend to use it generically. It’s such a great name.
Thanks for reading through this whole post. Here is your reward. I said that there wouldn’t be any pictures of pretty girls in this post, but I didn’t say anything about any pretty mermaids!
GET ME OUT OF HERE ...
Oh, and here's some kind of visitor flag counter thingy. Hey, all the cool blogs have one, so I should too. The Visitors Online thingy up at the top doesn't count anything, but it looks neat. It had better, since I paid actual money for it.
Thursday - March 24, 2011 
on 03/24/2011 at 11:55 AM
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