"Roll, roll, roll your boat..."

[sarongsong]

Go Navy!

September 15, 2009
...Makin Island is the first Navy vessel to combine gas turbines with auxiliary motors that run off the ship's electrical grid...will be commissioned here Oct. 24...the last of eight Wasp-class flattop amphibious assault ships delivered since 1989...and, at $2.5 billion, the most expensive...
San Diego Union-Tribune

[DrWho]

So it's a hybrid?

[pantaz]

Maybe I'm slow, but I don't get the, "Roll, roll, roll your boat..."

[Trebuchet]

Half a story there. What powers the "electrical grid" when the turbines aren't in use?

[tashirosgt]

A tangential question: What is the normal procedure when a warship docks - does it continue to generate its own electrical power or does it hook up to the local land power grid for the port?

[Hornblower]

I think the newspaper's description of the power plant is incomplete. In Googling for information I find nothing about storage batteries like the ones in hybrid cars. My best guess is that a small gas turbine runs an auxilliary power unit that can drive the propulsion motors efficiently at low speed, with the big main turbine kicking in when needed for high speed.

Cruise ships on pure electric power? No way. If I am not mistaken they are using Diesel/electric power.

It would not be the first time the media have messed up on technical items like these.

[DrWho]

In Googling for information I find nothing about storage batteries like the ones in hybrid cars.

Nope, and I bet it doesn't have regenerative braking!

[Gigabyte]

The diesel-electric power plant on the Elation and Paradise differs from the previous ships which had four Wartsila Sulzer 12ZAV 40S and two Wartsila Sulzer 8ZAL 40S diesel engines as prime movers.

Elation and Paradise have six Wartsila 12 V 38 (7,920 kW/600 rpm) medium speed diesel engines, with a total power output of 47,520 kW (64,600 hp).

These are placed in two separate engine rooms. Each diesel engine drives an ABB 11,000 kVA AC alternator supplying electric power to a main electric high voltage bus bar of 6.6 kV, 60 Hz, 3 phase, from which the main propulsion motors and other large consumers are supplied.

The power for the two syncronous electric AC motors located in the propeller pods of Azipods are controlled by cycloconverters supplied by ABB.

The electric motors have a power of 14 MW, 0 - 146 rpm, with double stator winding. Each cycloconverter consists of two three phase converters with a common control unit. Each cycloconverter feeds a three phase stator winding of the propeller motor.

The two Azipod units on Elation and Paradise replace the internal electric propulsion motors, shaft lines, rudders and rudder machinery and three 1,500 kW tunnel stern thrusters, found on the first six 70,400 GT/2,600 passenger Fantasy-class cruise liners built by the yard.

Fantasy 1990
Ecstasy 1991
Sensation 1993
Paradise Fascination 1994
Imagination 1995,
Inspiration 1996 etc etc

All these cruise ships use electrical generation, and since it has been twenty years, Joe is 100% correct.

And he should know, he own them.

[Gigabyte]

Of course the ship have batteries. They are for backup power.

[captain swoop]

It's a Diesel/Electric. A lot of big ships use electric motors.
Hybrid powerplants aren't anything new. I served on Steam/Gas Turbine hybrids thye 'Tribal' class Frigate. It cruised on steam turbine but could cick in a Gas Turbine for extra speed or a quick startup if it was caugh with no boilers in port.
'County' class destroyers had the same set up, effectively two of the 'Tribal' power plants.

[captain swoop]

Of course the ship have batteries. They are for backup power.

Very few though. Backup would be for emergency lighting and some radio gear. BAckup power is supplied by seperate diesel generator sets on anything bigger than a motor yacht. Engines are started by compressed air when you get up to the size of plant fitted to cruise liners or warships.

[Gigabyte]

Backup is important when everything on the ship runs on electricity.

[Gigabyte]

If anything goes wrong, you want backup power (UPS style) until the emergency generators kick in. Obviously vital on warships, but also very important on luxury cruise liners.

[captain swoop]

There again anything on a UPS would be limited to a few lectronics systems a 'minimum set'

On the Leanders I was on none of the Radar fit or the other Sensors like Sonar had any kind of 'battery' power, their current draw wouldbe far too much. Same for the main lighting circuit or the air conditioning. If we were going into any kind of 'action' then auxiliary generators would already be running, they are essentialy just the main generators running off the main boiler and a couple of Diesel sets for when there was no steam (In Port or if there was a loss of pressure), there were no seperate sets just in case of emergeancy apart from a couple of little portable units.

I suppose that on a small craft like a motor yacht or coastal craft (anything up to say 130 feet (say 500 tons) UPS and a seperate generator would be important but they would still just be powering some of the distress and comms circuits, maybe a sat phone and the SARSAT distress beacon but they should have their own battery supply anyway. A UPS coulod be useful if you are using a DIgital Chart system. Even my dad has one of those on his 40 footer.

[Hornblower]

I never meant to imply that a big ship would not have batteries for electrical backup in critical components. I was concerned that some readers might get the impression that an analogy to today's hybrid cars means routine cruising on battery power when the big turbine is not running.

[Gigabyte]

I never meant to imply that a big ship would not have batteries for electrical backup in critical components. I was concerned that some readers might get the impression that an analogy to today's hybrid cars means routine cruising on battery power when the big turbine is not running.

I doubt very much they would use batteries for just running.

But of course they run on batteries if the big turbines fail. Everything critical runs on batteries when there is a failure of the power generators.

Building a warship, or a cruise ship, that simply went dead in the water when the main power failed would be about as stupid as you can imagine.

Very few though. Backup would be for emergency lighting and some radio gear.

Wrong, wrong and wrong.

There again anything on a UPS would be limited to a few lectronics systems a 'minimum set'

More wrong. On modern electric powered craft, the ships key electronics, electrical services, lighting and emergency steering all run on a huge UPS system. Cruise ships are required to have at least a half hour emergency power.

I have no idea what a military ships reserve power is. But it is no doubt much more.

[BigDon]

A tangential question: What is the normal procedure when a warship docks - does it continue to generate its own electrical power or does it hook up to the local land power grid for the port?

Depends on the port and the ship. Plus one doesn't exclude the other. and sometimes ships supply power to small towns in emergencies.

[Trebuchet]

Depends on the port and the ship. Plus one doesn't exclude the other. and sometimes ships supply power to small towns in emergencies.

There was an incident in the 1930's in which a USN aircraft carrier provided power to the city of Tacoma, WA, for a spell.

[captain swoop]

I doubt very much they would use batteries for just running.

But of course they run on batteries if the big turbines fail. Everything critical runs on batteries when there is a failure of the power generators.

Yes but only a few emergeancy lights and other key systems like radio

Building a warship, or a cruise ship, that simply went dead in the water when the main power failed would be about as stupid as you can imagine.

Idf the engines stop then the ship is dead in the water. I have been on a warship that went dead because a gland on a joint in a steam pipe fractured. No turbine no way on the ship, we wallowed. All the turbo alternators stopped as well we were running on just the diesel set until they fired up the auxiliary boiler usualy used in port for steam power when the main boiler is out.
I can assure you that if the generators fail the power goes out apart from a few key systems and emergeancy lighting.

Wrong, wrong and wrong.

No not wrong, I speak from first hand experience in the Royal Navy and I can get my dad to come on and back me up, he is a Chief Engineer with 40 years experience on Tankers, Passenger Liners and Gerneral Cargo

More wrong. On modern electric powered craft, the ships key electronics, electrical services, lighting and emergency steering all run on a huge UPS system. Cruise ships are required to have at least a half hour emergency power.

Yes but what does the emergency power actualy power? Certainly not the main light and power circuits, certainly not all the fans and blowers. There will be reduced emergency lighting and some navigation and communication systems powered.

I have no idea what a military ships reserve power is. But it is no doubt much more.

You would be wrong if you thought so.

[BigDon]

Building a warship, or a cruise ship, that simply went dead in the water when the main power failed would be about as stupid as you can imagine.
.

This makes no sense when broken down. By definition power failure means you stop. Simply "losing the load" means you come to a stop. (Someone or something venting the steam from the propulsion system.)

On a warship, what do you think the main design concerns are going to be?

'Cause you have mutually exclusive design functions on a warship, those being offense, defense, range and speed/maneuverability. The increase of one is always at the expense of the others. Big honking batteries are heavy, affecting range, speed and maneuverability you could be using to not get hit in the first place.

Rob, have you ever lived on a warship or partipated in actual damage control? (non-snarky question, if you're an old sailor I don't have to explain as much.)

Damage on a ship grows, it doesn't remain static like a car on the side of the road. One of the reasons they liken ships to living things. I've had several fires on my ship that put us dead in the water. If you have to abandon main engineering because of smoke and flames, you're going to come to a stop.

Modern warships have a standard times 7 redundancy of critical electrical and computer systems, with a select few systems going to times 11 and they only stop there for weight. Using much more versatile diesel engines, not batteries. Batteries are NOT inert like a diesel engine with no fuel. Salt water and a cracked battery has always been bad news. Large batteries have a lot of other liabilities on a warship.

(Submarines only tolerated them as the alternative was even more dangerous.)

Why? Warships are expected to come under fire from artillery, torpedoes and air launched antiship missiles. Torpedos home in on your air/water interface (the hull being counted as part of the water) and uses a shape charge that can burn through ten feet of solid titanium.

And the *old style* Soviet ALCM's blew out forty frames! The ship launched ones are bigger. My old carrier had approximately 180 frames. That's a big bite. And in smaller ships a correspondingly bigger bite.

You are not going to design a mitigation for that with redundency and extra batteries. You use that space for sensors and weapons.

[captain swoop]

Just to amplify what BigDon meant, seawater in a battery produces Chlorine gas. There are very strict rules that cover how batteries can be fitted and vented on Merchant ships (See the SOLAS regs). As he says a Warship uses multiple generators and independant main circuits, each section can cross link or bypass damaged cables.
Damage control had a motto "Float - Move - Fight" In that order

[BigDon]

Also large damaged battery arrays also have a tendency to electrocute people on metal ships floating in saltwater oceans. And explode violently.Remember we are talking about battle damage, something cruise ship designers don't really have in mind. Battle damage being "applied destruction".

That's always different than "oops" or "get out of the way" type damage. The human element makes the difference.

[sarongsong]

So it's a hybrid?

Yes.

Maybe I'm slow, but I don't get the, "Roll, roll, roll your boat..."

Turbines + nursery rhyme + second-hand smoke drifting in from an adjacent thread...

Wow, BD, San Francisco almost got the nod for homeporting this behemoth, but for 'reasons we cannot discuss'...

[Gigabyte]

Yes but only a few emergeancy lights and other key systems like radio
Idf the engines stop then the ship is dead in the water.

Wrong.

This makes no sense when broken down. By definition power failure means you stop.

Wrong. That is the old way of thinking. Modern ships are not the same as the old ones.

Just to amplify what BigDon meant, seawater in a battery produces Chlorine gas.

Somebody should have told those old submarine Captains, you know, the ones that ran their submarines, under the water, on battery drives.

Also large damaged battery arrays also have a tendency to electrocute people on metal ships floating in saltwater oceans. And explode violently.

Just making up reasons to support a wrong position doesn't help. It wasn't hard using Google to find out that modern ships that are all electric use batteries.

But hey, if you still want to stand by your story, lets make it interesting. How much do you want to bet?

[Gigabyte]

Getting back to the new boat, they seem to be a little mum on just exactly what is meant by "the electric drive". What ever they are doing, it is saving a whole lot of fuel.

"At high speeds it runs on gas turbine engines and at lower speeds it runs on an electric drive -- just like a hybrid car," says Capt. Bob Kopas, Commanding Officer.

San Diego news

[sarongsong]

...they seem to be a little mum on just exactly what is meant by "the electric drive"...

"...It wasn't hard using Google to find out..."

...six diesel-electric generators...
naval-technology.com

[Gigabyte]

Yes, but what are they driving? The same props that the turbines are connected to? Or auxiliary thrusters?

[korjik]

If yall wanna get technical, USS New Mexico was launched with hybrid engines in 1917

[korjik]

Wrong.



Wrong. That is the old way of thinking. Modern ships are not the same as the old ones.



Somebody should have told those old submarine Captains, you know, the ones that ran their submarines, under the water, on battery drives.



Just making up reasons to support a wrong position doesn't help. It wasn't hard using Google to find out that modern ships that are all electric use batteries.

But hey, if you still want to stand by your story, lets make it interesting. How much do you want to bet?

No offence, but do you really want to tell a couple old sea dogs on how ships work?

[Gigabyte]

Are you saying you can't teach an old sea dog new tricks?