The misuse of RMS Titanic as a benchmark for ship size · PDF fileBenchmarks in popular...

Paul Stott

6th February 2014

The misuse of RMS Titanic as a benchmark for ship size

Benchmarks in popular reporting of Science

Popular reporting often makes use of tangible common objects to convey size

This is relatively easy with linear or square dimensions and weight

≡ 11 elephants


For ships the default is often to compare the ship to RMS Titanic to try to

convey a sense of a vessel’s size:

BBC Radio 4, Today Programme, 16th Sept 2013:

“Costa Concordia weighs twice as much as the Titanic”

ExtremeTech.com: “Costa Concordia: How a ship

twice the size of Titanic is being lifted from the seabed”

BBC Newsround, 16th Septeber 2013: “Costa

Concordia weighs twice as much as the Titanic”

Use of RMS Titanic as a benchmark

The intent of this comparison is laudable: it is to convey the heroic nature

of the salvors in man-handling something that is very large.

So, where is the problem?

≡ 2x


Problem number 1: The common misinterpretation of the meaning of Gross

Tonnage as a measure of weight.

46,320 Gross Tons 114,147 Gross Tons

BBC Radio 4, Today Programme, 16th Sept 2013:

“Costa Concordia weighs twice as much as the Titanic”

BBC Newsround, 16th Septeber 2013: “Costa

Concordia weighs twice as much as the Titanic”




46,320 Gross Tons114,147 Gross Tons

In terms of tonnage, Costa Concordia is 2.5 times the size of Titanic, so the

BBC’s statement appears approximately correct…..

except that tonnage is a measure of volume, not weight:

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In terms of tonnage, Costa Concordia is 2.5 times the size of Titanic, so the

BBC’s statement appears approximately correct…..

except that tonnage is a measure of volume, not weight:

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Tonnage was introduced as a means of taxing ships

according to their earning power, determined by their

carrying capacity.




1 Tun 46,320 Gross Tons114,147 Gross Tons

55,000 tonnese 52,310 tonnes

Full load displacement

When looked at correctly the two vessels weigh a remarkably similar amount:

Titanic was built with much heavier scantlings, was joined by millions of rivets

and was fuelled by coal…….


Problem number 2: does Edwardian engineering have any relevance as a

benchmark in the modern context?

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Fiat S74 – the leading Grand Prix car of 1912, the year of Titanic’s delivery from

Harland and Wolff

Can this car be used as a benchmark to convey the power of a modern F1 car in

any meaningful way?

190 bhp




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Stating that the F1 car has engine power equivalent to 5 Fiat S74 gives no

immediate tangible impression of how powerful a modern F1 car is.

The comparison conveys how relatively weak the 1912 car was, rather than

giving a sense of the power of an F1 car.

≡




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Fiat S74 – the leading Grand Prix car of 1912, the year of Titanic’s delivery from

Harland and Wolff, is equivalent in engine power to a modern family car.

≡




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≡

Stating that the F1 car has engine power equivalent to three Porsche 911s (and

weighs about the same as a large paper clip) gives the reader a direct impression

of how powerful the car is.

The Porsche provides a tangible benchmark that can be directly related to.




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The Edwardian products provide no tangible benchmark with which we can

intuitively gauge the size of a modern product.

Has the size of the Titanic any relevance in the modern context?

Was it a large ship?

Was Titanic a Large ship?

Titanic’s legendary status is based on a combination of a number of factors:

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1. The unprecedented level of opulence: a first class ticket to New York cost the

equivalent of £64,000 in today’s money.

2. The irony of the label ‘unsinkable’ that was attached to the ship.

3. The extent of the tragedy: the loss of 1,517 souls remains the 6th worst

peacetime loss of life at sea.

4. The catastrophic inadequacy of LSA regulations.

5. The moral bankruptcy in the correlation between wealth and chances of survival.

6. The ship’s size.

Without factors 1 to 5, Titanic would no longer be remembered as a paragon of size.

By 1936 the Titanic’s size had been exceeded by a factor of 2 (RMS Queen Mary)

and the Titanic has no more relevance than the Fiat S74 in the modern era

If the vessel were remembered specifically for size then the paragon would be

Olympic, the first of class that preceded Titanic.


Stating that the Costa Concordia is 40% larger than the RMS Queen

Mary or “twice” the size of the RMS Olympic or RMS Brittanic is clearly

meaningless and no-one would suggest these vessels as size

comparators in the modern context..

But it is the same thing as using Titanic as the comparator.

? 2x


But this does not mean to say that the Titanic may not be a good benchmark for

large ship size.

To judge whether Titanic was a large ship in her day we could use the same

benchmarking technique and compare the ship to other famous vessels.

Arguably, the most famous ship prior to Titanic in public consciousness may have

been Cutty Sark..

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1869

963 GT


Size of circles is proportional to gross tonnage:

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0

0.5

1

1860 1870 1880 1890 1900 1910 1920

Year of delivery

Comparison with Cutty Sark

(1869)

Titanic was 50 times larger

Perhaps not a fair comparison

as Cutty Sark is remembered

primarily for speed and good

looks


Rather than Cutty Sark, the prior paragon of size was probably Brunel’s nemesis,

the Great Eastern

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1858

18,915 GT

Great Eastern was

6 times larger than

any preceding ship

and it would be 40

years before

anyone tried to

build anything that

large again.

The ship was sadly

a technical failure.


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Comparison with Great

Eastern (1858)

Titanic is 2.5 times larger

0

0.5

1

1840 1850 1860 1870 1880 1890 1900 1910 1920 1930

Year of delivery



Other relevant ships of the Edwardian era:

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Typical transatlantic liner:

RMS Oceanic, 1899, 17,274 GT

Typical cargo liner:

SS Demodocus, 1912, 6,689 GT

Superseded record holder for size:

Mauretania, 1907, 31,938 GT

0

5

10

15

20

25

30

35

40

45

50

Demodocus Oceanic Mauretania Titanic

GT

Tho

usa

nd

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Titanic was:

2.5 x larger than the typical

transatlantic liner of the day

45% larger than the previous

record holder, built only 4

years previously

7 x larger than the typical

cargo liner of the day

By any measure at the time, therefore, Titanic earned the epithet “Leviathan”

The magnitude of Brunel’s challenge

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A digression:

The Titanic is remembered in popular consciousness as an epitome of a large

vessel.

But look at what Brunel achieved…

SS Great Britain

1843, 3,270 GT

The world’s first recognisably ‘modern’ ship:

Ocean-going, screw powered, 12 knots, made

of metal

0

0.5

1

1820 1840 1860 1880 1900 1920 1940

Year of delivery

The magnitude of Brunel’s challenge

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No wonder it killed him!


0

10

20

30

40

50

60

70

80

90

Demodocus Oceanic Mauretania Titanic Queen Mary

GT

Tho

usa

nd

s


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By any measure at the time, therefore, Titanic earned the epithet “Leviathan”

But by 1936 Titanic had been succeeded by a factor of almost 2x.

RMS Queen Mary

1936

81,237 GT

How does Titanic stack up against the modern fleet

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Having concluded that Titanic was a “leviathan” in the Edwardian era, does this

have any currency as a benchmark for the modern fleet.

How big is a modern large ship?

Costa Concordia, 2004, 114,147 GT

Queen Mary 2, 2003, 148,528 GT

Oasis of the Seas, 2009, 222,282 GT – the largest

vessel afloat in 2013

-

50

100

150

200

250

Titanic Costa Concordia Queen Mary 2 Oasis of the Seas

GT

Tho

usa

nd

s


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The largest ship in service is

currently almost 5 times larger

than Titanic.

Titanic is not a small ship in

the modern era (as

Demodocus would be) but is

no more than mid-sized.

Titanic was of a similar size to a modern North Sea ferry – not much of a

paragon of size in the modern era.


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The current equivalent of Demodocus is possibly a handysize or handymax

bulk carrier.

This is the most numerous sector of the commercial fleet and could be thought

of as a “transit van” of the shipping world.

c. 35,000 GT


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Titanic was about 1/3 larger than a handymax and a similar size to a modern

panamax…..

0

5

10

15

20

25

30

35

40

45

50

Demodocus Titanic Handymax Panamax

GT

Tho

usa

nd

s


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Titanic was only 50% of the size of a modern capesize bulk carrier (the shipping

equivalent of a bulk lorry on the roads), the main long haul vessel for coal and

iron ore.

Titanic was only 20% of the size of the largest bulk carriers shipping coal and

ore to China

0

20

40

60

80

100

120

140

160

180

200

Demodocus Titanic Handymax Panamax Capesize VLBC

GT

Tho

usa

nd

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The identification of the largest vessel afloat is debateable -

Maersk McKinney Moller, 18,000 TEU,

EEE, is 12% smaller than Oasis of the

Seas in terms of GT, but that doesn’t

include the boxes on deck.

With deck cargo the EEE could be over

250,000 GT, carrying the equivalent of 1.3

Titanics on deck!


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The largest ship ever was the ULCC Belamya, delivered in 1976, which was

275,268 GT.

This is due to be exceeded by a gas processing plant under construction at

Samsung, due for delivery in 2016, which will be 300,000 GT.

-

50

100

150

200

250

300

Titanic Bellamya Oasis of the Seas Samsung 2030

GT

Tho

usa

nd

s


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Titanic compared to the largest ships in the modern era:


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Titanic has no validity as a benchmark to convey ship size in the modern era :

1. It’s reputation for size is only incidental to its fame for other reasons;

2. It’s size was well superseded almost 80 years ago;

3. It would not have been a large vessel in the modern era;

4. It provides no tangible basis to give an impression of size – no-one living has ever

seen Titanic – its use as a benchmark is therefore meaningless as well as arbitrary.

This leaves us with a need to find a benchmark that can convey ship size to a

lay audience:

Benchmarks for ship size

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Titanic has no validity as a benchmark to convey ship size in the modern era :

What parameter could be used to properly convey the magnitude of the task that

salvors were undertaking in trying to right the Costa Concordia?

It has to be on a similarly immediate basis to the use of Porsche to convey the

magnitude of an F1 engine power.

≡


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The problem lies in the fact that GT is a volumetric measurement and the comparator

therefore has to be volumetric.

It is tempting to suggest a linear measure could be used and this would be more

accessible to the audience – length and weight are the most obvious candidates.

≡

26 Double decker buses

10,000 male African elephants

The length parameter does not convey the size of the vessel adequately

10,000 elephants is better in this context but appears a little arbitrary and out of scale.


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The real problem with linear measurements is that they are not consistent in terms of

benchmarks between ship types.

Comparing length would suggest that and Costa Concordia is only about 8% larger

than Titanic – because of the very different block coefficients of the two ships (c.66%

for Titanic and c.76% for Costa Concordia)

-

50

100

150

200

250


GT

Tho

usa

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Comparing weight would seem to provide an obvious answer giving a direct

indication of the size of a ship to which we can relate. But there are two problems…

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GT

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Problems with using weight

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1. Problem # 1 is that weight is not a commonly reported parameter, so is difficult to

find.

2. Problem # 2 is that where weight can be found it is normally displacement, not

lightweight, and this leads to inconsistencies between ship types.


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Comparing weight would suggest that Titanic and Costa Concordia are about the

same size

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50

100

150

200

250


GT

Tho

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Comparing light weight would suggest that Oasis of the Seas is about double the

size of Bellamya

Comparing displacement would suggest that Oasis of the Seas is only about 20% of

the size of Bellamya

-

50

100

150

200

250

300

Titanic Bellamya Oasis of the Seas Samsung 2030

GT

Tho

usa

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The benchmark has to be volumetric to be consistent with GT.

It has to be capable of assimilation by the lay reader/viewer to give an impression of

volumetric size.

The most commonly used parameter

for volumetric comparison is the

“olympic-sized swimming pool”.

Unfortunately this is too small for use

with ships, at only around 900 GT.

Costa Concordia is equivalent to 126

swimming pools is as arbitrary as

using elephants to compare the

weight.


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The ideal comparator would be:

• Between about 30,000 and 100,000 GT

• Between about 85,000 and 283,000 cubic metres

• Between about 3 million and 10 million cubic feet

This means that the most likely candidates are buildings.

The problem is that building volumes are rarely quoted – architects deal in linear

dimensions and floor area.

This just means that comparators are difficult to find – there isn’t much of an

alternative given the requirements for scale above.


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The first attempt was sports stadia – but they tend to be too large.

MCG = 600,000 GT* Wembley stadium = 400,000 GT

Stating that Costa Concordia is around ¼ the size of Wembley stadium loses any impact

* Moulded volume


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Large religious buildings provide potential but reliable volumes have not been found.

St Peter’s Basilica = 424,000 GT Saint Paul’s = 55,000 GT (un-verified)


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Stating that the Costa Concordia is equivalent in size to almost 2 St. Paul’s puts

into perspective the size of the job that the salvors were trying to achieve in

parbuckling the ship!

= +


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The next large spaces tried were concert venues.

Happily there is a credible source for auditorium volumes:

Beranek’s book lists the acoustical properties of the

world’s major concert venues, including the internal

volume of auditoria.

Leo Beranek, acoustic engineer, USA, b. 1914


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Some are too large:

Millennium dome – 850,000 GT


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Most, even the large ones, are unfortunately too small:

La Scala, Milan – 4,000 GT Carnegie Hall, New York – 8,600 GT


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Only two well known spaces fall within the required size bracket:

Royal Albert Hall, London – 30,000 GT Great Hall of the People, Beijing– 32,000 GT

人民大会堂


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Stating that the Costa Concordia is equivalent in size to almost 4 Albert Halls or 4

人民大会堂 puts into perspective the size of the job that the salvors were trying to

achieve in parbuckling the ship!

=


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Stating that the Costa Concordia is equivalent in size to almost 4 Albert Halls or 4

人民大会堂 puts into perspective the size of the job that the salvors were trying to

achieve in parbuckling the ship!

But only if these benchmarks mean anything to the audience.

To be effective, the benchmark needs to be localised within the experience of the

intended audience.


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Finally, an iconic building was sought in London that might be useable.

Norman Foster’s “Swiss Re

Headquarters”, affectionately known as the

“Gherkin”.

Appropriate for marine use as it was built

on the ruins of the Baltic Exchange at St

Mary Axe, following the detonation of a 1

tonne bomb on 10th April 1992.

It is also mercifully regular, having a

circular cross section for its full height,

enabling volume to be calculated by

Simpson’s rules, based on a sectional

drawing.


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Norman Foster’s “Swiss Re

Headquarters”, affectionately known as the

“Gherkin”.

128,500 GT.


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=

Stating that the salvors of the Costa Concordia

are attempting to man-handle an object the size

of a sky scraper, London and the UK’s third tallest

building, really puts into perspective what they

achieved that day.


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Stating that the salvors of the Costa Concordia

are attempting to man-handle an object the size

of a sky scraper, London and the UK’s third tallest

building, really puts into perspective what they

achieved that day.

But only if you know what the ‘Gherkin’ is!

Adding that it weighs 55,000 tonnes is also helpful – if you can find a lightship value.


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I stopped there, because I had work to do!

Other localised benchmarks are needed:

• Burj Al Arab, Dubai?

• PSA building, Singapore?

• Australia Square Building, Sydney?

• HSBC Building, Hong Kong?

When you have an idle moment, please

consider adding to the list.


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