QE2 Engines (diesel-electric powerplant)

[Beardy Rich]

Some fascinating questions posted and good that Skilly is able to answer them.
With regard to the query about the relative thermal efficiencies of the Diesel-Elec set-up and QE2s old steam plant... I believe that the current set up is significantly more thermally efficient.

Anyone know about Rankine Cycles? (No connection to pushbike manufacturers) 

[skilly56]

Hi Rich,  I hope the weather has been coming right for you up there - Rosie did the right thing and jumped a ship heading for warmer climates.

Re the thermal efficiencies, I looked up some recent notes and came up with these figures:

Large marine diesels - direct drive - 50 to 53 %.

Marine diesels with diesel electric drive are about 45 to 48% efficient. They lose a little bit (about 5%) in the electrical generation and propulsion motor losses, but in QE2's case, this loss was acceptable as they were achieving huge efficiency gains by removing the steam plant anyway.

Steam plant for electricity generation - about 33.5% efficient. However, if you can build a steam power generation station beside a coal field and a good river flow for condensing, or on a natural gas supply, the efficiencies increase.

Petrol engines - about 25 to 30% efficient.

The latest types of Brayton cycle gas-fired co-generation electrical generation plants can be way above 50% efficient - some are now able to be built with theoretical efficiencies up to 80%+. Steam powered Rankine cycles don't quite get up to this level though.

With the latest changes to the MARPOL emmission rules, more and more ship owners are going to look towards gas-powered ships to comply with the laws. You don't actually need a lot more bunker space for the gas - you just need a hell of a lot of refrigeration machinery to keep the gas cooled to a liquid state, and what does cook off you burn in the engines (reciprocating & turbines).

Cheers

Skilly

[Beardy Rich]

Hi Rich,  I hope the weather has been coming right for you up there - Rosie did the right thing and jumped a ship heading for warmer climates.

Cheers

Skilly

Thanks for supplying the figures Skilly, I had an idea you'd come up trumps and be able to answer the questions regarding thermal efficiencies.

Rosie has done the right thing and got away from this cold, damp weather. It's miserable here I can tell you.
What is it they say about the weather? Britain has weather, everywhere else enjoys a climate!!!

[bobso]

Here is a link to a video of the massive engines on QE2--never seen this before but apologies if it has been posted

[Twynkle]

Hi Bobso
Thank you for posting that wonderful big sound!
Here's the link to lots more about QE2's engines
Enjoy!
https://www.theqe2story.com/forum/index.php/topic,1039.0/all.html

Rosie

PS - In case you haven't found it,
there's a really good way of discovering topics and all sorts of interesting things
by inserting the appropriate word via the  advanced search window.
It's on the forum index /home page, up on the left hand side!
You'll be amazed to find so much there!

[Isabelle Prondzynski]

Thank you for this fascinating video, bobso.

As you rightly guessed, this video also appears here in the Forum :

https://www.theqe2story.com/forum/index.php/topic,1032.msg20572.html#msg20572

A good method of checking, as Rosie suggested, is to introduce all or part of the hyperlink into the "Advanced Search" box and see what it brings up. You will find the "Advanced Search" command at the top of each page, right beside the Search box.

[bobso]

Thank you Isabelle and Twynkle--i enjoyed looking at the page with the engines big sound. I will take your advice in future and check the "Advanced Search" box. I am so enjoying my time on the Forum and am learning new things every day. It makes a real difference to have fellow enthusiasts help people like myself navigate round the large range of topics about the QE2. So, again my sincere thanks.

[Rod]

Bah. Going around the world on a series of mis-timed explosions!

[Twynkle]

Bah. Going around the world on a series of mis-timed explosions!

Rod - In some ways you make it sound a bit scary, on the other hand, like most engineers, maybe it was also a case of, 'Everything is just about do-able" -
It seems so easy to idealise everything about the old girl - however, I bet there were times when you should have been rewarded danger money as compensation for not only for keeping her going, but also staying alive as well!
When you hear/ read things about her length of service - are you surprised she managed 40 years?
I would guess she must have required running repairs daily, hourly, even - perhaps
and some pretty dodgy situations to deal with besides - bet the logs made impressive reading too! 

[Rod]

To be honest....
I think that most Engineering types on here will agree.
There are things we did, that we never thought we could do, never should have done probably never been done before.
I would also suggest that that is the same with virtually every Merchant Ship in the world.
I don not tell half of what I know, neither, I suspect do others, because, frankly, most wouldn't believe it.

[Isabelle Prondzynski]

I don not tell half of what I know, neither, I suspect do others, because, frankly, most wouldn't believe it.

Mind you, you're in a good place here -- we are among friends, and ready to believe what anyone knowledgeable about QE2 tells us about our ship! So just go ahead!

But keep your best stories for 1 April next year, won't you    ...

[Rod]

Mind you, you're in a good place here -- we are among friends, and ready to believe what anyone knowledgeable about QE2 tells us about our ship! So just go ahead!

But keep your best stories for 1 April next year, won't you    ...

I never lie!
My mother taught me that...hard!

[Twynkle]

A superb image of QE2's new engines taken on April 25th 1987
Posted on the Shipspotting site 
http://www.shipspotting.com/gallery/photo.php?lid=1398052
By Bob Scott

[Rob Lightbody]

A superb image of QE2's new engines taken on April 25th 1987
Posted on the Shipspotting site 
http://www.shipspotting.com/gallery/photo.php?lid=1398052
By Bob Scott

Great photo!  But there's a mistake in the text - it says 25.5 knots when it means 28.5 knots.

[Alistair]

It also says it was done in 1967 at Bremerhaven......I don't think so!
Good picture all the same