Empress Engine Trouble

Announcement from Captain ab 30 min ago. Itinerary changed from GC and KW to Nassau, Coco Cay and KW. One engine having problems, so can't maintain necessary speed. Refund of 10% of cruise cost as OBC. Ship is lovely; enjoying the trip, regardless!

Oh My:eek:

I would love that change!

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Not surprising. It was running rough last week. Extreme vibration and one of the props not running.

I would love that change!

 

 

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You'd love Nassau over Grand Cayman? Now I've read it all! :eek:

Don't mind the itinerary change. Not too many unhappy ab it. Sitting in VCL, ship seems to be rolling a bit, but not bad. Lounge is filling with young adults now. Off to bed!:)

You'd love Nassau over Grand Cayman? Now I've read it all! :eek:

Maybe they want to go to the Pirate Museum.....who knows?

You'd love Nassau over Grand Cayman? Now I've read it all! :eek:

No! Hate Nassau... really love Coco Cay [emoji177]

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Announcement from Captain ab 30 min ago. Itinerary changed from GC and KW to Nassau, Coco Cay and KW. One engine having problems, so can't maintain necessary speed. Refund of 10% of cruise cost as OBC. Ship is lovely; enjoying the trip, regardless!

Not surprising. It was running rough last week. Extreme vibration and one of the props not running.

Well, the vibration is most likely not caused by any engine problem. The vibrations capable of being felt up in the passenger areas would be from harmonics between the rotational speed of the propeller and the hull's natural frequency. Most times you can work up or down an rpm or two to get out of the harmonic range, but this isn't always possible while meeting the itinerary.

Empress has a rather unique propulsion system in that it uses 4 diesel engines coupled directly to the two propeller shafts, unlike the more common diesel electric system where the diesels generate electricity which powers electric motors on the propeller shafts. Diesel electric allows one diesel engine to be down for maintenance, but the other diesels are cross-connected to both propellers and generally can provide enough power to drive the propellers at full speed.

Empress goes further in uniqueness, by the fact that the 4 diesel engines are of two different sizes (power ratings), with one larger and one smaller engine on each propeller. This gives some of the flexibility and fuel efficiency of diesel electric, but only in fixed steps, based on the size of the two engines.

While you may have seen one wake look less than the other, I would be surprised with this propulsion system if one was not turning at all (even freewheeling). Running two engines on one propeller (8Mw), and maybe only the small engine on the other (3.2Mw) would produce different wakes, and also would produce some more vibration, without there being any problems with the engines. Maintenance is required on engines, so every diesel engine is taken out of service periodically, and it may just be that one larger engine needed maintenance (not repair), and the required speed by the schedule required this unfortunate combination of engines and propeller speed that caused the vibration. Now, not being able to make full speed and meet an itinerary without all engines running is a problem with direct diesel drive, which is why all newer cruise ships have gone to diesel-electric drive.

Many people don't know that the diesels on the cruise ships are overhauled while still in service, and an overhaul lasts 2-3 weeks, so the odds are pretty good that most everyone here on CC has cruised on a ship with one engine down for maintenance the entire cruise, and never knew it. Ships are generally designed with more generating power in the diesels than is needed to power the lights and provide enough speed to meet the itinerary, and still have one engine down.

I haven't been to Nassau in years but I'm like you - roll with the change and enjoy the 10% back.

NCL cruises

2012 Pearl

2014 Dawn Forums

I haven't been to Nassau in years but I'm like you - roll with the change and enjoy the 10% back.

 

 

NCL cruises

2012 Pearl

2014 Dawn Forums

There isn't much else to do....visit the Pirate Museum in Nassau. The next time we have a port stop there, that is what we plan on doing....I have heard it is interesting.

Announcement from Captain ab 30 min ago. tinerary changed from GC and KW to Nassau, Coco Cay and KW. One engine having problems, so can't maintain necessary speed. Refund of 10% of cruise cost as OBC. Ship is lovely; enjoying the trip, regardless!

Aside from this little itinerary change.....glad to hear you are enjoying the cruise. Any more specific comments would be very welcome....we sail on her August 25.

are the engines on the empress the original engines from when the ship was built ?

Wonder how much money Royal has lost with this disaster that is Empress of the Seas?

are the engines on the empress the original engines from when the ship was built ?

I thought I answered this yesterday, maybe I fell afoul of the moderators, I'll try again.

Yes, the "engines" are the same as when she was built (almost certain, but they could have changed one or more out, not real common). The engines are overhauled usually every 12,000 running hours (about 2-2.5 years). This overhaul tears the engine down to the bare block, and everything is cleaned, inspected, and renewed as necessary, under the direction of the original manufacturer's tech rep. Even the cylinders are replaceable, the liners lasting most times around 36-48k hours. So, in effect, every 2.5 years you have a new engine. The life expectancy of a marine diesel "engine" (the actual block) is virtually infinite. They will normally only change out a complete engine if they have had a serious fire (and I know Empress had one engine fire), or if they had a catastrophic failure like a seized piston that punches out the side of the engine.

Chengkp75

We are on the next sailing. Do they usually correct the engine problems at sea, or can I expect problems or delays on our sailing.

Thank You

Tami

Chengkp75

 

We are on the next sailing. Do they usually correct the engine problems at sea, or can I expect problems or delays on our sailing.

 

Thank You

 

Tami

It all depends on what the problem is. If it is minor, it could have been corrected within hours, but still have affected the last itinerary. If its a major problem, it may take a week or two to fix. Again, with Empress' configuration, they can take one engine off line for repairs, but depending on which engine it is, and what speed is required to make the schedule, they may have to adjust port calls.

Thanks for your response, it is very informative.

Chengkp75, this is very encouraging news for those of us sailing in a few weeks. Thanks!

Empress has a rather unique propulsion system in that it uses 4 diesel engines coupled directly to the two propeller shafts, unlike the more common diesel electric system where the diesels generate electricity which powers electric motors on the propeller shafts.

Wow, this shocks me, diesel electric has been around for a real long time. I wonder what the thought process was behind doing this on the Empress, it's not like they don't have to use it to run the lights and etc, why not just run the drive also.

Chengkp75 -

Thank you very much for the reply.

Tami

Wow, this shocks me, diesel electric has been around for a real long time. I wonder what the thought process was behind doing this on the Empress, it's not like they don't have to use it to run the lights and etc, why not just run the drive also.

Well, the late '80's and early '90's (Empress was built in '89) was the real change over time from diesel drive to diesel electric for cruise ships. While electric propulsion has been around for quite a while, in order to vary the speed of the propeller, you had to either use a DC motor, with its inefficiencies and maintenance, or run the AC propulsion system at varying frequencies, which required running the generator at varying speeds, so you had to have a separate "propulsion" bus at varying frequency, and a hotel bus at constant frequency.

It was not until you could build very large, high power, variable frequency AC drives, that diesel electric power really took off. These drives take the 60Hz power from the generators, convert it to DC, and then convert it back to AC electronically altering the frequency of the output AC. This allows an efficient AC motor to run at variable speed.

I need to stop reading these Empress threads. Just show up at the pier and hope it is there and assume we will go to the ports advertised with air conditioning, working plumbing and less than half of brunches with a free alcoholic drink as advertised.

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I'm sure in due time Empress will work out it's flaws

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