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					MARINE           PROPULSION         ENGINES:         THE       FAILURE         OF     CORPORATE

RJF Hudson, CEng BAppSc PhD DMS Extra First Class Cert                 FIMarEST MIMechE MCMI

          This paper gives a short review of the origins of internal combustion and compression
          ignition oil engines and their relevance to ship propulsion. Advances in steam turbine
          technology due to Parsons, culminating in Michell’s tilting-pad thrust block are also
          discussed. Michell’s invention was crucial to the implementation of the large diesel and
          turbine powers in service at sea, today. The paper concludes by observing that in the
          known face of global warming and environmental pollution, coupled with the known
          imminent scarcity of oil, no new feasible and innovative commercial ship propulsion
          technology is projected or has been forthcoming since the days of Rudolph Diesel, 100
          years ago.

The Background
Although this paper deals with the present and the future, it depends upon reference to some
great engineers of the past who created new technology from their intuition and experience,
rather than any use of science. They were lone pioneers whose inventions revolutionised the
world’s existing technology.          Their relevance to marine engineering can never be
When the compression ignition oil engine was considered reliable enough to be useful to the
UK manufacturing and transportation industry at the commencement of the 20th century,
crude oil was about US $31.001 per barrel and the supply was generally considered to be
limitless. This was the period when world sea-borne trade was flourishing and it was when
the luxurious passenger ships, Carmania, Mauritania, Lusitania, Carpathia and Titanic held
sway upon the Atlantic ocean. In that era ocean going ships were customarily driven by
triple expansion engines using steam at 200 psi provided by coal fired Scotch-type boilers

Author’s Biography
Richard Hudson joined The Indo-China Steam Navigation Company (Jardine Matheson & Co) of Hong
Kong from Australia, as a junior marine engineer in 1951. He obtained his First Class Steam Certificate
in London in 1955 and First Class Motor Endorsement at Newcastle-on-Tyne in 1960. He completed his
UK Extra First Class Certificate by examination held in Hong Kong and is the only marine engineer to
do this. He was appointed a seagoing Chief Engineer at 26 years of age in 1956, Assistant Superintendent
Engineer in 1962 and Chief Superintendent Engineer in 1968. He was awarded a post graduate Diploma
in Management Studies (HKU) in 1972. He retired in 1974 but was retained by his employers for many
years as a consultant. He received his BAppSc (1987) and PhD (2002) from Queensland University of
Technology. He was a founding committee member (secretary) of the Hong Kong Branch in 1965 and is a
Past Branch Chairman. He is presently a member of the Queensland Panel IMechE.
    Value expressed in 2005 US$
without superheat, but Charles Parsons’ new steam turbines were increasingly being
considered, to provide the necessary higher powers for the faster speeds required by the
owners of these new ships. Parsons’ new designs of turbines could much more efficiently
handle the exploitable heat drop of larger volumes of steam, thereby providing the bigger
powers needed, than could reciprocating engines. For this and other reasons turbines were
therefore gaining increased favour. The fact that turbine machinery could also deliver greater
power than reciprocating engines for equivalent weight and engine space was of additional
advantage. Even though turbine design was in its infancy, the initial turbine sets designed
without superheat by Parsons, operated with economies of the order of 20% better than the
economies of reciprocating engines.

Improvements in design
Subsequent turbine designs accommodated the application of higher steam pressures and
temperatures. This was the period when the metallurgists and the boiler designers were
unsung heroes. It was they who facilitated an alteration in the course of marine engineering
and ship propulsion by introducing higher quality corrosion resistant metals.                 The
introduction of new steels and new manufacturing processes enabled the use of superheated
steam from new high-pressure water tube boilers fired by furnace oil. This combination of
superheat and higher steam pressure reliably enabled the provision of greater power with
improved fuel economy. Furthermore it enabled a reduction in operating manpower that
steam reciprocating machinery using coal fired boilers, could not match. However at its
best, turbine general efficiency was less than 14.5%. While this poor efficiency was clearly
not to their liking, the owners of land based electric power generation industries and other
major industrial entities fortunately had a ready supply of available coal. Often the coal
supply was in the vicinity of their industrial site. However for shipowners the issue of fuel
consumption efficiency was of crucial concern. This was because their ocean going ships
were restricted to travelling distances that accorded to the availability of fuel supplies at their
ports of call, coupled with their vessel’s bunkering capacity. Clearly the carriage of bunkers
disadvantaged the amount of cargo carried. This concern about shipping distance had been
translated into the construction of the new Suez Canal, put into operation by 1870. For
similar reasons the Panama Canal was put in operation by 1914. These new trade routes were
crucial to Britain and Europe’s continuing economic expansion which required enormous
quantities of raw materials. The raw materials were mainly drawn from Africa, Asia and the

Far East. Sea borne transportation was clearly crucial to sustaining the UK’s wealth and
productivity, and as a consequence it was a time when Britain’s shipping industry with its
naval protection was dominant. The world’s incalculable economic growth was being
powered by the easy availability of Persian Gulf oil, perceived to be limitless. While most
UK naval ships had already been converted to using boiler oil, the UK ships that voyaged the
long distances for commercial purposes were powered by slow speed reciprocating engines
that were fed by steam from coal fired single-ended Scotch-type boilers. Steam driven
reciprocating machinery had made huge developmental strides from the mid nineteenth
century, but in parallel with this steam progress came the implementation of internal
combustion reciprocating engines that were fuelled by coal gas. Lenoir in France had a
patent in 1860 and several hundred of his gas-air mixture combustion engines ignited by a
spark, were produced.

Otto, Ackroyd Stuart and Diesel: the creation of internal combustion engines
The era of the internal combustion engine really began with the introduction of the four-
stroke engine conceived by Nikolaus Otto in Germany in 1861, with a practical engine
appearing in 1876. There were a number of other designs conceived around this time but all
of them, including Otto’s, used a pre-mixed charge of air and fuel. The mixture was induced
into the cylinder by suction which was followed by its compression and ignition using an
electric spark or by other means. However in the last decade of the nineteenth century two
further significant steps in the evolution of the internal combustion engine were taken. One
was due to Herbert Ackroyd Stuart of Yorkshire who, in 1890, patented an engine having the
principle of drawing in atmospheric air and compressing it into an intensely heated vaporiser
and at the desired point of this compression stroke a measure of liquid fuel was forced in
spray form into the vaporiser. The immediate increase in pressure caused by the combusting
air-fuel mixture propelled the piston to form a working or second outward stroke. This was a
successful compression ignition engine. The other step was due to Rudolph Diesel who, in
1892 patented an engine having principles similar to that of Ackroyd Stuart’s concept except
it proposed using pulverised coal as fuel. In parallel with M.A.N of Augsburg, a four stroke
engine using high pressure air to blast liquid fuel into the cylinder, was ultimately developed.
With a compression pressure of 425 psi and blast air pressure of 1000 psi, a thermal
efficiency of 26.2% was achieved. This was the highest thermal efficiency obtained to that
date in a heat engine.

Crossley, Mirrlees and R Hornsby & Sons
By the turn of the century engines of the Ackroyd Stuart design were in regular production
but they required a pre-heated combustion chamber to start. During their production in the
UK, they were being progressively improved upon in the works of R. Hornsby & Sons. The
UK Mirrlees Company had also arranged licences to build the Diesel direct injection engine
and the first British made engine, developing 20 bhp at 200 rpm, was operating in 1898.
Distillate fuels and various types of lubricating oils were in plentiful supply from 1870
onwards thus ensuring that limitations to the size and power of compression ignition engines
had been reduced to those of materials, lubrication, manufacture and design.
The Mirrlees Company had struggled to overcome fires and explosions in the engines they
had manufactured. These fires were caused by the inappropriate properties of the lubricating
oils being used. As a consequence, Mirrlees’ recognition of the importance of oil viscosity
caused them to formulate and use a suitable straight mineral lubricating oil.          Oil ring
lubrication was generally introduced when the hydrodynamic nature of lubrication became
better understood.    Crossley Brothers of Manchester had been licensed early on to
manufacture the Otto engine and began its production in 1876 using coal gas as fuel. They
too, quickly adopted mineral oils for lubrication. But if any period is to be identified as that
where theory and science are translated in practical mechanical success in the field being
discussed, the author suggests that 1900 is the period. The demand for great engine powers
could not properly be met by existing engines. Steam reciprocating engines were not up to
the job and to their discredit they had to be removed from the Manchester Power Station
because of noise. Parsons turbines were improved during production but their rotating
weights, together with the weights of their attached electrical generators, all supported by
whitemetal bearing surfaces, caused problems.

Parsons turbines
There were also two additional important drawbacks at that time in the design of Parsons
turbines. The first was blade tip steam leakage and the second was the need to accommodate
axial end thrust on the rotor. This end thrust was caused by the difference in steam pressure
that prevailed between turbine-cylinder steam entry and exhaust.         Figure 1 depicts the
problem of blade tip steam leakage. The manner adopted to prevent this was by fabricating
circular shrouds and installing them to the tips of the fixed and moving blades, as shown.

Working steam became trapped in the annular spaces formed by the shrouds and was thus
effectively constrained to do its job with greater efficiency when it expanded through the
blade-pairs. Obviously the smaller the blade tip clearances then the better the steam seal and
the higher the efficiency.
Figure 2 depicts the way that the axial rotor thrust caused by the difference in steam pressure
between steam entry and exhaust, was handled. Steam pressure equalising pipes produced
balancing forces on the rotor. As can be readily inferred from the depictions, turbines were
in their infancy and while more or less satisfactory to the high power duties required on land,
it was a different matter where ship propulsion was concerned. As yet there was no way the
larger turbine powers now available could be comfortably converted into the thrust
deliverable by the propellers of the big fast liners being launched.

     Figure 1

   Figure 2

A G Michelle – the vital contribution
In 1883-4 Mr Beauchamp Tower discovered hydrodynamic lubrication.                     He was
investigating the problems of oil lubrication of bearings, in railway axle boxes. His paper to
the Institution of Mechanical Engineers at the time reported his seminal results.
He showed that it was possible for a journal to drag oil between the shaft and its bearing by
virtue of the fact that the centre of the rotating shaft shifted away from the centre of the
bearing in such a direction as to make the film of oil thicker on the ingoing than the outgoing
side.   Osborne Reynolds extended this work in 1886, and provided the mathematical
solutions to the differential equations describing the hydrodynamics involved.       Reynolds
explained mathematically the phenomena of film lubrication. He incorporated allowances
for the variation of viscosity with temperature, all of which were verified practically.
However where Reynolds found it suitable to avoid the problem of mathematically
explaining side oil leakage by assuming bearings of infinite width, Michell did not.
Michell’s analysis of the film lubrication problem included the effects of side leakage.
Where the previous analysis had employed difference and differential equations, Michell
utilised the more advantageous Bessel Function mathematical approach to provide improved
solutions. In his analysis of the inclined slider bearing, side leakage effect was included.
Michell combined physical insight with impressive mathematical skill. His patent in 1905
incorporated the fact that maximum bearing oil pressure occurs beyond the centre of the
bearing face. Slider-film bearing pads that tilted were the eminently successful Michell
Whitemetal faced flat collar-type thrust pads were limited in use to a direct loading of say,
70 psi, with an oil film coefficient of friction of say, 0.03. Michell’s tilt-pad design enabled
a whitemetal face load of say, 500 psi. Moreover and with great importance, his design
reduced the coefficient of friction to say, 0.005. The effect of these results allowed for a
dramatic increase in the relative velocity between the thrust pads and the thrust faces. A
marine engine developing 35 000 shp produces at 18 knots a thrust of approximately 200
tons. Instead of a multiple collar thrust having say, 6 400 sq in area of thrust pads, Michell’s
design only needed say, 900 sq ins and the friction heat generated and the wear of the
surfaces was minimal. Given that Michell’s tilt pad design ensured continual complete
wetting of all bearing surfaces, cooling the working lubricant contained in the bearing thrust
block using fresh water through cooling coils was also minimal.

Figure 3 shows the design of the multicollar thrust used by early Parsons turbines. The
design maintained the operating rotor in position relative to the stationary blades when
working under steam. Figure 4 shows the application of Michell’s invention to a Parsons
turbine rotor. Note how Michell’s thrust unit encompasses the capability of accurately
adjusting the axial position of the rotor relative to the stationary blades to minimise blade tip
steam leakage.

The first ship to make full use of the Michell thrust block principle was the 25 knot twin
screw Parsons turbine passenger ship Paris, built by Denny of Dumbarton in 1913. Figure 5
depicts a marine propulsion engine thrust block of the Michell design that in principle has
been common to all ships from its inception.       The block shown has 6 tilting bronze pads
faced with whitemetal. Circulated cooling water conducts away the fluid friction heat.

In the 1920’s and 30’s great practical skills reposed in the craftsman who built ships and their
propulsion systems.    Arc welding of all types including gas-shielding techniques were in
common use. The water tube design of steam boiler originally patented by George Babcock
and Stephen Wilcox in 1867 was now capable of pressures of 450 psi at 750° F. Craftsmen
were making intricate high pressure steam turbine casings and boiler valves of cast steel

while the associated massive gearwheel casings were of cast iron . Pinions were forged from
nickel steel and gearwheels from cast iron or cast steel with carbon steel rims. All gear wheel
and pinion teeth were machined to very high accuracy.

Combined with a turbine driven boiler feed pump system, the plant was extremely simple to
manufacture and very reliable in operation.          The knowledge of the day adequately
encompassed simple geared torsional vibration problems and any critical speeds that were
determined were easily catered for by adjustment of rotor and shafting stiffnesses. Turbine
propulsion sets delivering ten thousand horsepower were not uncommon. They all used
Michell thrust pads to position and to adjust the rotors.

Steam turbines had found favour with ship owners because of their simplicity and power, but
it was obvious to them long before the Great War, that for equivalent powers with all things
being equal, compression ignition oil engines would be cheaper to run.

Figure 3

Figure 3

           Turbine Rotor – Michell Adjustable Thrust Block Assembly

Figure 4

Figure 5                       Michell Thrust Block

In that period a coal fired triple expansion engine had a brake thermal efficiency of about
10.3 per cent. An oil fired steam turbine set produced a brake thermal efficiency of about
16.3 per cent. Diesel engines on the other hand offered brake thermal efficiencies of 34 per
cent and 31 per cent, four cycle and two cycle, respectively. If we use the Titanic’s coal
consumption of 650 tons per day as an example, then had four stroke diesel propulsion using
furnace oil been feasible, an equivalent fuel cost saving of say 400 tons of coal per day
would have been achieved. This clear cost saving was the stimulus for marine engineers to
build ever bigger compression ignition oil engines to suit the size of the ships being ordered
to ply the rapidly expanding Atlantic passenger and cargo trades. In the forefront meeting the
demand, were the oil engines created by Harland & Wolff for the Georgic & Britannic, two
luxurious trans-Atlantic passenger liners built for the White Star Line in 1930-32.

Figure 6 shows a section through the double acting four stroke engine built by H&W for the
Britannic. Two 10 cylinder 13,000 bhp engines of this design powered the ship. As can be

seen, these massive engines were of enormous complexity with a large number of big
wearing parts. Equally ambitious and labour intensive were the huge opposed piston two
cycle engines built by H&W in the same period. These engines exhausted their gases and
inducted their combustion air by means of pistons reciprocating past inlet and outlet ports
positioned at the top and bottom of each cylinder. This approach did away with cylinder
poppet valves and their drive gear but the sealing of gases blowing past each main piston rod
where it passed through the centre of each bottom exhaust piston was among many
unacceptable operating problems. See Figure 7. An engine cylinder air blast fuel injection
valve is depicted in Figures 8 and 9. The air blast is on the left with fuel entering on the right.
Technical progress in fuel injection took a major step in 1927 when the solid injection fuel
system conceived by Bosch was adopted. The Bosch pump employs a solid steel cylindrical
plunger driven by a cam to force the fuel out of the pump at great pressure to the injection
valve. Among the first major engine builders to incorporate the improvement was the
Doxford Engine Works of Sunderland. At one stage post WW2, about 1600 Doxford oil
engines of the design shown in Figure 10 were at sea. That is more than 60 years ago.

Today’s engines are built using highly advanced machine tools. They are cleaner to operate,
considerably more reliable, and translate oil fuel into propulsion power much more
efficiently. But with oil prices now reflecting the end of the limitless oil era, what happens
next in the evolution of marine propulsion?             So far, neither science nor industrial
technology has presented any feasible alternative to what we’ve been doing at sea for more
than a century.

In short, and as a corollary to the history just presented relative to engine inventions, no
conclusion to this discussion is more important than to appreciate that for more than 100
years, oil fuel has been driving world prosperity, and it continues to do so today, without any
successor in sight.

Figure 6
Figure 7


Figure 8                  Figure 9

Figure 10

The history of the professions is the history of specialisation
So where do we go from here? The author suggests that a good start can be made by
understanding that society’s present standard of living is chiefly owed to lone brilliant
engineers of the past, with those already mentioned having notable inclusion. As has been
discussed, more than 100 years have passed since Nikolaus Otto, Ackroyd Stuart and
Rudolph Diesel revolutionised the way to produce usable productive power by means of
mechanical engineering. Since then as a result, progress has developed with incalculable
benefit to the world, and compression ignition oil engine powers have risen from Dr Diesel’s
original 20 bhp to the huge 100,000 bhp oil engines used at sea, today. Marine steam
propulsion has likewise evolved from primitive steam reciprocation methods through to
today’s modern high speed turbines capable of providing even larger propulsion powers.
Society in its present form could not exist without these engines. Nothing could have
liberated society as effectively as these engines and the oil that powered them.

We should also remind ourselves that it is exactly 100 years since AG Michell patented the
thrust pad concept which enables these immense powers to be safely translated into the
propulsion of today’s ships of momentous size. Ships today could not do without Michell
design thrust blocks. Also, today’s diesel engines incorporate among other modifications the
latest technology in ceramics, variable valve timing and fuel injection.           The newest
applications of electronic devices are common place. The future of oil engines includes even
higher compression and combustion loads, all to the end of squeezing out more power, as has
been done for the last 100 years, merely by modifying existing engine technology. Where is
all this leading? What will be the end point and what will be its circumstances as oil
becomes more costly and scarce? The last giant oil field was discovered more that 35 years
ago. With North Sea oil production known to be in rapid decline it is only a matter of time
before greater EU dependence on Middle East oil eventuates, with deleterious effect upon
EU economies. Arising as a corollary to this are the questions as to whether the Middle East
has the oil deposits today claimed by it and what will be the overall effects of the demand for
oil by say, India and China. Certainly oil as we know it can eventually be sourced from coal
and oil sands, as known wells deplete, but at what cost to the consumer and to the
environment? Today a marine diesel engine delivering 100,000 bhp at 102 rpm uses about
300 tons of fuel at a rough fuel cost of US $60,000 per day, producing some 950 tons of
CO2 plus other exhaust gases. It weighs 2300 tons and has a 300 ton crankshaft. In spite of

the immensity of these engines, fuel economy direction will continue to stimulate the
enlargement of engine sizes but only until the commercial risk of failure involving such
usages becomes unacceptable. Then what happens? Whether or not the new designs of highly
efficient steam boilers using composite combustion fuels with their turbines, can eventually
compete economically with compression ignition oil engines, remains to be seen.

The failure of corporate innovation
There is nothing new in the diesel-electric combinations of machinery currently being
installed. These principles were in practice long before World War 2. There is also nothing
new in gas-turbine-electric combinations, either.        Furthermore, the machinery being
promoted today as new, is merely modification of existing technology. This includes diesel
engine-exhaust and gas-turbine conceptions, coal water slurry fuel technology, and
circulating fluidised-bed automatically-fired boilers. In the author’s view these are mere
improvements upon the past, when the urgent need now is for new technical creativity.The
seemingly conformist approach by today’s corporate oil engine builders, who are crucial to
the future of marine propulsion technology, does not encompass the promotion of radical
new technical departures and great invention. Their industry approach, together with that of
the oil production industry, who also have a major vested interest, is uniform, and is certainly
not producing innovation. It may even be stifling it. Their goal today is merely to develop
better fuel efficiency coupled with ecological protection. Their corporation design criteria
seems completely focused upon achieving consumption economies, not radical technology
change. Any handicaps they have appear to be about environmental concerns, rather than by
any lack of ability of the present day engineers and metallurgists to build bigger engines,
which is all that they are doing. The author suggests their focus should now be upon
sweeping innovation and new technology rather than merely re-adjusting things of the past.
This is where corporate innovation per se, is a failure. Conjecturally we might ask “Where is
the next Rudolf Diesel?    Where is the next Anthony George Michell? Where are the next
true, private inventors?” It is a fact that any driving force towards innovation – an essential
prerequisite to a steadily rising standard of living, largely depends upon the incentives
offered. The author offers the view that any application of a new technique or a new
invention is much more likely to come from a directly rewarded engineer than from any
Corporate “team”, whose participants get no proportionate independent financial rewards,
and who have had their possible ownership patents pre-assigned to their employer.

Finally, as an associated matter, it seems worthy to repeat here that the effects of global
warming, sea pollution and depleting oil reserves are causing considerable alarm. No doubt
this matter is getting major attention but it is difficult to conceive of a better way to advance
society’s welfare than by Government’s involvement in promoting debate about what the
future has in store for marine propulsion. But those Western Government’s who should be
stimulating debate upon this issue appear to have joined industry’s laissez faire approach,
seemingly in the hope that innovation and national interest will thrive if left unencouraged.
Could it be that today’s continued WW1 political and commercial linkages between the Old
Governments and the oil producers and industries, that were based upon the historical
concept of a limitless cheap oil supply, continues to discourage innovation to the extent of
remaining unchallenged? Just as concerning in the author’s view is the seeming lack of
interest by the professional engineering bodies as to the need to create debate about the future
of marine engine innovation and the need for radical change. It is hard to imagine a greater
benefit that they could bring to mankind than to publicly recognise the current vacancy of
leadership in this issue, and champion now the role of the engineer in society.

If the aspirations of the world’s people for a full measure of social wealth are to be fulfilled
with an ecological face, then only radical and new departures from existing technology can
suffice, not new grease for the same wheel. We should therefore be appealing to men and
women of original and unorthodox minds. As a priority we should be studying ways to
remove any training and education rigidity where it conflicts with the goal of originality and
unorthodox innovative thought.

Cargo ships will only get bigger, more sophisticated and more expensive. Excluding 903
container ships now on order, there are 1100 new oil tankers and 884 new dry bulk carriers
collectively worth US$51 billion2, on order today, swelling the global fleet by more than
20% in the next three years, all engined on principles 100 years old. No clear new innovation
strategy exists. Perhaps a century after Rudolph Diesel and Charles Parsons invented new
fundamental engines, commercial nuclear propulsion is now in the offing, whether we like it
or not in this age of acts of terror. Nuclear propulsion will require advanced practical
training and scholastic preparation.

Perhaps propulsion will be by an engine of some revolutionary feasible concept as yet
unannounced. Let us very much hope, so. But will it happen before fuel oil reaches, perhaps,
US$250 per barrel? We must wait and see.

    Bloomberg Report May 5th 2005

The diesel engine drawings are abstracted from Marine Diesel Oil Engines - A manual of
marine engine practice 9th edition, Sothern and Bowden (authors), James Munro & Co Ltd
Glasgow (publishers). The steam engine drawings are from Verbal Notes and Sketches for
Marine Engineer Officers 18th edition, JWM Sothern (author), James Munro & Co Ltd
Glasgow (publishers). The author thanks the publisher for permission to use the drawings.


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