QM2 speed vs QE2 speed

[Rob Lightbody]

I've been talking to someone who knows about these things...  I had been thinking that QM2 was just a bit slower than QE2, but not too bad.  Nearly 30 knots vs 34 knots sounds OK.  But I think the reality is nearer an 7/8 knot difference in reality (maximum flat-out speed being rarely used).

QE2 could fairly effortlessly travel at 28-29 knots day-in, day-out and exceed 30 knots almost by accident, even without all engines online.  She was seen passing the IoW a year ago at over 30 knots, for instance.

With rising fuel prices, QM2's very thirsty gas turbines will be rarely pressed into service, and without them I think her speed is only in the mid 20s (can anyone confirm an exact figure)?  I think they may regret choosing them (even though they had good reason to). Her original design was for 2 diesel engine rooms, but they dropped the 2nd one to free up more room and imrpove the layout.

QE2 presumably used about double the fuel at 29 knots than at 23 knots (7/8 engines vs 3/4).  Whats the same figure for QM2, and am I right?

I think we've all been on board QE2 when she was well above 23 knots, even on my med cruise she was frequently travelling at over 28 knots - so it can't have cost so much as to have been disallowed.

The one good thing, looking to the future, is that presumably her turbines can be fairly easily replaced if more efficient ones come along that burn the heavy-fuel that the diesels do (these are being developed apparently).

I have a copy of "Genesis of a Queen : Cunard Line's Queen Mary 2" here, it was put together by/for Alstom's Chantiers De L'Atlantique by "The Naval Architect" when they completed her.  Its a gem of a book, and goes into huge detail.

[Jeff Taylor]

I think we've  all heard that QM2 did a fraction over 30 kts on  her trials,so she is a few kts slower than QE2.  My only firsthand observations would be that she routinely did 26-27 kts on the LA-Honolulu leg of her world cruise two years ago and that was on only 3 pods with the fourth nothing but add drag.  Now I have no idea what the fuel consumption was althugh I have to assume that one or both of the gt's were in use.  On the other hand, 22-24 kts was more typical shuttliing between closely spaced Caribbean ports.  My guess would be that she would probably be pressed and uneconomical to do a steady 30 kts, but she certainly can handle 28.

[Rob Lightbody]

I think we've all heard that QM2 did a fraction over 30 kts on  her trials,so she is a few kts slower than QE2.

First trials - 29.21 was her highest speed (corrected for light trials displacement and swell)
Second trials - 29.63, corrected for swell, wind, displacement and power - 0.3 knots above what was predicted.

Zero to 28 knots takes 7 minutes, by the way!

Source - "Genesis of a Queen, Alstom/Chantiers De L'atlantique/a Naval architect publication.

John Maxtone Graham's EXCELLENT book concurs, but states that there were times when she actually topped 30 knots.

What I want to know though is not her maximum flat-out speed, but her top realistic in-service speed... its this figure that i think is so substantially less than QE2's.

[Jeff Taylor]

One of the documentaries about her (QM2's) construction did emphasize that she was designed for a 5-day crossing, which seems to imply that she could maintain a 28 kt service speed, although we all know there's a dramatic trade off going to 6 days or more considering dramatically lower fuel consumption and the additional bar/casino revenue.  Doubtless QE2 has a bigger reserve of speed, but let's face it--both ships have fundamentally the same type power plant except for the all diesel vs diesel/GT mix.  Why would one set of diesels/alternators/electric motors be inherently more robust than another.  I guess we'll just have to leave it that QE2 is faster hands down, but even she wasn't all that economical to run flat out.

[Rob Lightbody]

Pedant Rob here again!

I would love to see an authoratitive reference that QM2 was designed for a 5 day crossing - if she was, she'd be substantially the slowest ship ever to attempt it at that speed, and would have to run at very close to her maximum trials speed the whole way across!  I will rummage in my books again to see if I can find anything...  She'd have no scope to make up lost time.  She'd have had to be able to exceed 30 knots in service.  The only reason QE2 can exceed 30 knots, with redundancy in reserve, is to maintain the 5 night crossing.

When did QE2 switch to 6 night crossings?  i.e. at what stage in QM2's planning did it occur?

I was told that the turbines make a big difference, and are essentially not used, and will not be even more as fuel prices continue to rise.  This is in addition to the difficulties of them using different fuel. 

[Jeff Taylor]

Rob: wish I could recall which program it was, but I do remember Stephen Payne making that statement.  I also would be interested in when they lengthened QE2's crossings--quite logical in view of the economics plus trying not to put excess strain on the aluminum superstructure.  Obviously they must use the GT's on QM2 to some extent as they blew one in Norway, I believe it was, during her first year, and they do constitute about 40% of her total power, and some of the RCI ships are predominantly GT.  In fact, I hear they're developing some that will run on heavy marine distillate, so that should change the equation.  We may not know the final answer, but as I said before QE2 is clearly faster--in fact faster than anyone would design a liner today based on pure economics, and Mickey is a man who knows economics.  Good discussion!!

[flagship]

QE2 switched to the six-night crossing in 1997.

[cap0557]

Interestingly in 2010 QM2 will introduce 7 night crossings...

[andyh]

On my several trips on the QM2, during the mid-day reports, and the navagation infomation on the tv channel, she was often traveling at between 26-28 knots

[Cruisemarsh]

QE2 could outpace QM2 very easily as she has a few knots more speed.

The fastest QE2 travelled when I was on her was 31knots.

The fastest the QM2 travelled when I was on her was 24knots.

(but obviously these aren't the top speeds, but 24 knots for a cruising QM2 is very respectable as most cruise ships only reach 19/20 knots)

[MiamiCunarder]

  While on a visit to QE2's bridge on a Caribbean cruise in April '98, I recalled looking at a speed gauge that had her going at a steady 30 knots. I wonder if she was trying to catch up for lost time. I never asked.



Ron

[junglejames]

Everyting ive seen seems to suggest the QM2 can go about 24/25 knots powered just by her diesels. This increases to her top speed of 29/ 30 knots with her diesels and turbines.
Her service speed has been put down somewhere as 26 knots although with cruise ships service speed is really, the maximum speed. Whilst onboard QE2 for a run between Vigo and Bilbao, I worked out that she would need to go about 30 knots to get to Bilbao on time, even if leaving Vigo on time, and that is exactly what we were doing. So they were obviously happy for QE2 to go over her supposed service speed in normal operations.

Fuel efficiency wise, Stephen Payn told me that with both ships going 28knots, the QM2 used less fuel than the QE2, even with gas turbines running. However everything I have seen since, suggests that at 28 knots, QE2 uses less fuel.
So I think sayng both ships use about the same amount of fuel at 28 knots is fair. However get both ships down to about 24/ 25 knots, where the QM2 doesnt need her turbines, and the QM2 will be using less fuel due to the higher efficiency of pods, over traditional props.

James

[junglejames]

Oh, one question. Im sure I saw somewhere that in bad weather, the QM2 (despite being more comfortable) needs to slow down more than the QE2.
Anyone know if this is true?

James

[Clydebuilt1971]

Whilst on a return transatlantic on QM2 in June we experienced a Force 10 two days out of NY. The ship was travelling at 26knts and remained so for most of the two days that the weather was foul. We were told that the speed was reduced to 23knts during the night for comfort reasons.
When we eventually came out of the weather speed was increased to 30.5knts and remained thus until we were one day out of Southampton. QM2's seakeeping during those Force 10 days was excellent and afterwards looking over the side as this leviathan charged through the (now calm) waters of the atlantic at 30knts was a sight to behold.

Let us not forget one thing. QE2 was built to maintain the atlantic service in all weathers at any time of the year. Fast forward to QM2 and the business had changed. The 6 night crossings are this length to give people more time on the ship and the illusion of better value for money etc etc. Remember this is a holiday for most.

The 7 night crossings were to be introduced Eastbound as the bookings in that direction were weak compared to Westbound. Cunard apparently (we were told) thought that the additional night would perhaps attract more passengers. I suppose the loss of the hour most nights during the crossing can make you feel a bit groggy? 

Dont get me wrong, coming from Greenock, Scotland I am furiously proud of QE2 and all the other vessels that slid down the various building ways into the Clyde over the years but I personally am very fond of QM2 - she does what she was designed to do and does it well. She does have a link to the Clyde albeit tenuous in that the St Nazaire yard which built QM2 was originally developed all those years with assistance from Scotts of Greenock - at one time the oldest shipyard in the world.

QE2 was a flier in the old tradition but I think it is unfair to compare the two as they are very different animals and I admire and hold a glass to Cunard / Carnival for having the guts to build QM2 in the first place.

 

Gav

[Rob Lightbody]

Great posting Gav, thanks!  There's only one reason why Cunard are increasing the crossings to 6,7,8 nights, and thats to make more money !  People on board spend money, and the ship saves on fuel...

Very surprised (but delighted !) to hear that she exceeded 30 knots... can't imagine she will be doing that again though, given her new timetables. 

4 things are now putting me off doing a transatlantic on her - in order - (1) I have no money !, (2) she doesnt dock in Manhattan any more (3) she doesn't "rush" like QE2 used to and (4) I didn't like her all that much when i visited her (although she is very, very impressive).

[Clydebuilt1971]

Oh aye, forgot to add that apart from the weather we left NY almost 1.5hrs late due to a poor Canadian couple whos flight was 14hrs late! QM2 had cast off and was basically stopped about 100m from the berth when the Police launch suddenly rushed towards the quayside to a small group. They duly boarded the launch which then headed out towards us. At this time one of the hydraulic platforms used for tendering was lowered and deck crew appeared. The launch came alongside and the Canadians plus their luggage were boarded to a rousing cheer from the decks and balconies above.

Exciting start to any holiday!!

We then proceeded to sea with an excellent commentary from liner historian Bill Miller who also gave some fantastic lectures in Luminations during the crossing.

Thanks for the kind comments Rob.

Gav

[rough crossing]

I too had (have) my reservations about QM2 - but I decided to give her another go and booked the last Eastbound crossing of 2009 hoping for rough weather and just to try and relive the Maiden transatlantic when we hit a storm. Well I wasn't disappointed and in true liner style QM2 ploughed on through what I suspect turned out to be the storm that hit Cockermouth subsequently. I was up on the bridge viewing gallery quite a bit and the crew were obviously quite excited taking pics of enormous waves coming over the bows - Capt Bates just calmly carried on sipping his afternoon tea and I noticed we did slow to between 15-18knots. He later confirmed that during the night we passed at least two ships that were 'hove to'. So despite the reservations, QM2 kept going, kept to schedule, breaking only a bit of china - what other current passenger vessels can do this?   

[Peter Mugridge]

If I may make a suggestion, perhaps prospective passengers should invest in a wrist worn GPS unit, like joggers use?

You could then check the speed ( in mph, so needing a little maths to get the speed in knots ) on deck at any time without having to find a screen displaying the speed.  Imagine it - being able to check the speed while lying down in a deckchair on the sun deck or whatever the QM2 equivalent of that is.

[highlander0108]

If I may make a suggestion, perhaps prospective passengers should invest in a wrist worn GPS unit, like joggers use?

You could then check the speed ( in mph, so needing a little maths to get the speed in knots ) on deck at any time without having to find a screen displaying the speed.  Imagine it - being able to check the speed while lying down in a deckchair on the sun deck or whatever the QM2 equivalent of that is.

That is a great idea.    I could take along my handheld portable Garmin GPS that I use on my boat, but it does need to see the sky so it would only work on deck.  One more thing to pack next time.....

[Twynkle]

Hmm...
Just a thought - why not persuade all passenger ship owners to equip passengers with mini portable consoles
with - ship's speed and direction, wind speed and direction, sea state etc, potential hazards, points of interest, Daily Programme,  ETA, and very importantly - an email facility, regular updates from the Bridge, ECR, and Radio Control Room  - a sort of Ship's 'Blackberry' / Tablet/ i-book?
This would mean that certain passengers already addicted to sightseeing-at-sea could remain on deck for the entire voyage - with the exception of 'time -off' for the occasional visit to the Chart Room - all in exchange for additional free on-board spending pennies.  Mmm.

[Peter Mugridge]

Highlander, a GPS should work inside as long as you're next to a reasonably large window, unless it's got metallic anti-sun coatings.

My Garmin works on virtually every train in the UK ( the only exceptions being the Voyager and Desiro family of designs ).

[andyh]

I too have used my hand held Garmin to check speed and location, a great little toy 

[holynougat]

Some interesting ideas in this discussion!
Some facts to consider –
QE2’s engines used just under 2 tonnes of HFO (heavy fuel oil) each per hour, so with everything on line she would be using 18 tonnes of fuel per hour.

QM2’s Diesel engines use about 4 tonnes of HFO per hour and the GT’s use about 7 tonnes of MGO (marine gas oil) which is essentially Diesel every hour. The Gas Turbines use fuel almost proportional to the engine load, so unlike the diesels which use pretty much the same amount of fuel regardless of load the turbines will use about half as much fuel at 50% load than they would at 100% load, making them quite a flexible power plant. In summary then, QM2 will use about 30 tonnes an hour at full speed, but you must consider that MGO is about twice as expensive as HFO.

There have been many discussion about the QE2 being able to ‘easily exceed’ 30 knots, but towards the end of her service life while she still could exceed 30 knots (an amazing feat) she could not do considerably more than that. I have seen the QE2 doing 34 knots Over the Ground, but this was due to substantial favourable current through the Straits of Gibraltar. I worked on the QE2 for several years and never saw 9 DG’s online because the Propulsion Motors could not handle the power produced (the 9th DG was pretty much a reserve so that the rolling maintenance program with 1 DG being overhauled could be carried out while the ship was at sea)

To answer some questions about the QM2, she can achieve about 23.5 knots in dead water on 4 DG’s, anything over that and she needs to use the GT’s. While there is a reluctance to engage the GT’s if at all avoidable, the ship is regularly scheduled to operate at speeds over 23.5 (every transatlantic)
 
To answer another question about the QM2 needing to reduce in Heavy Weather more than the QE2, in some ways this is correct, the QM2’s huge bulbous bow makes the ship more prone to ‘pounding’ than the QE2 was, due to her fine bow profile, however, this only really takes effect when the sea is on, or just off the bow. Apart from that situation QM2 would not need to reduce any more, infact probably less so than the QE2.

With regard to the QM2’s top speed, she will do around 28.5 / 29.0 knots if required, however, her engines are limited to just under 90% of maximum so she could do more in theory if the limiters were removed (don’t quote me on that!) provided the Pods could actually provide the extra RPM.

Before all the QE2 fans start sending me hate mail, I will agree that the QE2 was quicker than the QM2, but not by 6/7 knots as some people have suggested, and any mention of the QE2 doing 36 knots, without favourable current (which I saw posted somewhere)  is ridiculous.
HN

[Peter Mugridge]

That's very interesting, thank you. 

Can I just ask for comparison, prior to conversion to diesel, what QE2 could have theoretically achived in dead water with her steam turbines running absolutely flat out and how much fuel she would have consumed then?

[holynougat]

QM2 doing 31.8 Knots Over the Ground.

[holynougat]

To highlight my point about the bow.

[Imonlygoingforone]

QM2 doing 31.8 Knots Over the Ground.

Yes, with 4 kts up the chuff!! Let's see 30 in dead water please 

[Rob Lightbody]

Yes, with 4 kts up the chuff!! Let's see 30 in dead water please 

I like you already! 

[skilly56]

Peter,

I recall having read somewhere that the steam turbine installation produced 110,000 shaft hp, for a trials max of 32.5 knots. Rich will correct me if I am wrong, but the ships 'hotel services' and electrical load would have been covered by the turbo gennies, which ran independantly of the propulsion turbines. I do not know if these TG's ran on steam from the 3 main boilers or whether there were smaller boilers for the them.

The diesel electric installation when new produced 126,675 electrical hp (ie, 9 x 10,500 kW), but the 'hotel services' and 'in-house' electrical loads are now provided for by the main propulsion generation system - ie, the electricity for these loads is supplied by the 10,000 volt main generators (the DGs), which also provide the power for the propulsion motors. Whatever electrical capacity remaining after the ship's 'in-house' loads are catered for is what is utilised by the two 44 megawatt (118,000 ehp) prop motors (PM's). So, it would appear that the fastest speed QE2 would ever have done in 'dead water' would have been on the builders sea trials, when the in-house electrical loads would have been at a minimum because there would have been no passengers (walking cargo!)on board. In this condition, the ship's loads would have been at a minimum, leaving the maximum generator output possible for propulsion.

The diesel electric system is also affected by temperatures. In higher temperatures, the electrical resistance of the power generation, transmission, and propulsion motor systems rises, and so heat losses within the system begin to mount and the usable output to the propulsion motors reduces. Good cooling of all the electrical systems is essential, and ships can always go faster on cold nights because the diesel engines love the colder air (more dense), and the electrical losses in the propulsion system are at a minimum.

One twin-screw diesel electric ship I was on in the 1970's suffered severely in the warmer summer temperatures as insufficient air cooling was available for the generators and prop motors, so we always had to slow down on the hot days, then try and make up time during the cool of night.

So. what I was eventually getting to, the maximum speed on the diesel electric system in dead water, is the 33.8 knots that Rob refers to. I think this speed is also stated in Carol Thatcher's book. When determining the max trials speed, many runs are carried out each way over the measured mile, the average speed is calculated, and any tidal and weather effects are then calculated out. The manufacturer must achieve the customer's required trials speed or severe financial penalties can be incurred. So, the hull is new (or in as-new condition in this case), the props are polished, the cooling systems are 100 % effective, and the sea trials are then carried out in the calmest conditions available to determine the maximum speed the ship will ever achieve in 'dead water'.

One thing also to be considered here is that QE2's propellers were changed after the Grimm wheel failures on the first speed trials as a D.E. ship. I think they went from 6-bladed hubs to 5-bladed hubs about a year after the failures, but one would hope that the later blade design was more effective. So, was the max speed of 33.8 knots set with the 5 or 6 bladed hubs? The change may have had no affect at all if the blade area of the 5 blades was the same area as the 6-bladed hubs. It may have actually been beneficial, as the 5-bladed hubs may have reduced the high-load cavitation slightly. I have just had another look at the current propeller photos, and they actually have an incredible blade area for 5-bladed prop, but this is what was needed to transmit the available horsepower.

About March or April 2008 the QE2 passed Madagascar enroute to Walvis Bay, and the engineers fired up a DG that had not been run for 10 months (had been under heavy maintenance). They put this generator on-line with those already in operation and just let her go. With assistance from the current, the ship sat on 32 knots-plus all the way down the African coast. I have this info from one of the navigating officers on watch at the time, but unfortunately he cannot remember exactly how many DG's were on line.

Enough waffling from me - time to go.
Cheers
Skilly

[Beardy Rich]

Peter,

I recall having read somewhere that the steam turbine installation produced 110,000 shaft hp, for a trials max of 32.5 knots. Rich will correct me if I am wrong, but the ships 'hotel services' and electrical load would have been covered by the turbo gennies, which ran independantly of the propulsion turbines. I do not know if these TG's ran on steam from the 3 main boilers or whether there were smaller boilers for the them.

Hi Skilly, the three turbo-generators ran on steam from the 3 main boilers.

[holynougat]

With regard to QM2's speed, as I said top speed in dead water is around 29 knots realistically, however, I have seen close to 30 through the water.

In the picture she is doing 27.7 knots through the water, although the log did tend to read low so it would have been around 28.5 in reality.

[Rob Lightbody]

Just asking this again really... could QM2 maintain the same transatlantic schedule that QE2 did from 1969 until 1997?  I think not, for the reasons below, using facts posted above by people more knowledgable then I am.  I think, therefore, that she must have been engineered for a 6 night crossing, as QE2 was doing after 97.

According to the posts above, she'd basically be flat-out the whole way which would mean she could not maintain this schedule as she'd have no scope to make up time.

Also, would she have enough fuel to do the entire crossing at full speed?  30 tonnes per hour is quoted above.

Thanks.

[holynougat]

In perfect conditions assuming no mechanical problems then the original schedule would be JUST about possible on QM2 - however, any bad weather or engine problems would mean a delay - westbound speed would be around 29 knots, coming back however, it would not be possible on QM2 to make the speed as it would be around 32 knots. Knowing the QE2 it would seem likely that she to would be unable to average those speeds in bad weather, so I suspect that she used to arrive late regularly? - Not sure if anyone has any info on that.

As for fuel, no problems there! - QM2 can carries around 5000 tonnes.

[Jeff Taylor]

Yes, the fuel.  From what I've heard QM2 typically loads +/- 4,000 tons of Bunker C, and +/- 1,000 tons of marine gas oil for the turbines, a 4/1 ratio, yet the turbines put out 70% of the output of the four diesels.  I'd love to know the price difference per ton between the two fuels.  It must be very substantial.