An Interview with Parks Stephenson

Parks Stephenson

He was the Project Manager and chief forensic analyst in the team of Naval Architects who investigated and analysed the Titanic wreckage. The results of the findings were featured in a National Geographic special, while he co-authored and illustrated the book, "Exploring The Deep: The Titanic Expeditions" with James Cameron.

Graduating in Naval Science from the United States Naval Academy, Parks has had a dynamic multidisciplinary career all along. Currently, he works as the Systems Engineering Manager at Moog Inc. 

In this interview with Learn Ship Design, we get a glimpse of the challenges faced in the expedition and similar marine forensic projects and the secret behind his success in multidisciplinary efforts.

It You were an integral part of the research outcome of Titanic’s so called Achilles Heel. In reference to that, how would you describe the structural problems Titanic had ?

I don’t find that the Olympic-class ships had any significant structural weaknesses.  When I first started studying Titanic, the fact that she broke apart during the sinking seemed to suggest that there might have been some sort of structural weakness somewhere.  But after years of study of both the Titanic and Britannic wreck sites, where we could, for the first time, look at the wrecks from an architectural perspective, we increasingly found evidence that the design of that class of ship was actually quite robust.  Britannic’s structure has not noticeably sagged despite her lying on her side (where the loads are different than the structure was originally designed to support) and the fact that Titanic’s mid section broke into large chunks (with decks still supported by large uptakes) demonstrate that the H&W engineers took measures to mitigate potential problems in their up-scaling of previous designs.  Added to this was Olympic’s maintenance record until her end of life…she required no more, and maybe even less, re-work to her structure than her peers in order to keep her in service.

Share with us one unforgettable moment that you came across, during the Titanic’s scientific expedition. 

My most memorable moments came during the discovery of the Marconi and Turkish Bath rooms.  I had done much research into those rooms beforehand and it was interesting to compare what I expected to what was found.  In the case of the Marconi Room, it was entirely unlike what we expected.  In the Turkish Bath, it was almost exactly what we expected. The lessons learned from this experience helped to shape my forensic analysis going forward.  Another single moment happened during my dive to the wreck.  Our submersible passed over the starboard fidley grate that Lightoller claimed to have been first pinned against, and subsequently expelled from, that grate.  Unseen in the 2D imagery, but obvious when seen with the naked eyeball, was that the grate in question is actually bulged out from some pressure originating from within the ship.  This was physical confirmation of Lightoller’s account, which was very exciting to see…the past had a physical connection to the present.

What according to you, are the fundamental barriers faced during any marine forensic project?

The main barrier is time and budget…there never seems to be enough of either.  A wreck’s exploration does not submit easily to someone’s planned budget or schedule.  In Titanic’s case, especially, another factor is the pre-conceived notions of an entire community of “experts” and enthusiasts, who will defend what they think they know of the story against any rebuttal, any evidence, against it.  Unfortunately, in a popular story like Titanic’s, there is also a lot of pseudo-science conducted in order to make headline-grabbing charges, like we saw recently with the “brittle steel” and “weak rivet” theories.  For example, actual scientists would demonstrate the fragility of a steel under freezing conditions without really understanding the historical context; in this case, not accounting for the fact that there was an operating boiler room, generating heat in excess of 100 degrees F, on the other side of the steel.

Your journey from being a Naval Officer to working on the aeronautical sphere, then as an analyst in marine investigation, authoring books and producing documentaries and movies. How has it been all through? What is the driving force behind the multi-disciplinary You, Parks?

I have a natural curiosity that drives me in more areas than just Titanic. I feel that mysteries can be solved if we can just look past the myths that grow around the events and see them from their most fundamental perspective. In order to distinguish myth from fact, though, one needs evidence, and in the case of Titanic, the wreck itself is our last and most definitive source for evidence. I am not interested in just Titanic, I want to understand what really happened in history so that we can learn, and react to, the correct lessons today.

Should students pursuing Naval Architecture be academically exposed to guided projects related to marine forensics? Do you think that would create a better understanding of the subject if universities took this initiative? 

Any forensic effort should of course include schooling in the basic disciplines to that effort.  But one should also be more rounded, so that one can “think out of the box.”  A naval architect, for instance, should strive to sail in the ships in which he/she builds (or similar).  But even that’s not enough.  If one is exploring a shipwreck, one must also understand the time period in which she sailed, understand the thought processes of the individuals who sailed in her…see the world of that time through their eyes.  Myth begins when people put their own perspectives, their own time prejudices, on a study of the past.  When a story becomes too pat – as is Titanic’s, in my opinion – then that is the time to question our understanding. To answer your question properly, though, I do believe that any education into a given forensic field should come with practical experience. It is not enough to just learn about the subject, one must also practice it before one can really become qualified.

Parks, Titanic II hopefully sails out in 2016. Will you take the first voyage? 

If a berth is offered to me, I will go. But I am somewhat ambivalent to the entire project.  There is no replicating Titanic, no matter how exact they capture the details of the original.  In my opinion, there are actually attempting a replica of Olympic.  Titanic is really nothing more than Olympic with a disaster added, and since they cannot offer a disaster as part of their cruise package, the ship can never be Titanic.  Besides, the new ship can never BE the old ship…we live in a different world than the one in 1912.  You will be sailing on a ship whose design is not suited for the modern commercial world, with modifications to try and make it competitive enough to stay economically viable.   As students of naval architecture, pay very close attention to any news you can gather about how the ship’s construction is progressing, and how often the design will change during the course of construction.  Ask yourself…what kind of ship will result?  Will she be a treasure, or a mongrel?

Highly Mechanised Weapon Handling Systems

The Queen Elizabeth Class aircraft carriers will be the biggest and most powerful surface warships ever constructed for the Royal Navy and will represent a step change in capability, enabling the delivery of increased strategic effect and influence around the world.

  

The Queen Elizabeth Class will be utilised by all three sectors of the UK Armed Forces and will provide eight acres of sovereign territory which can be deployed around the world. Both ships will be versatile enough to be used for operations ranging from supporting war efforts to providing humanitarian aid and disaster relief.

                                

Highly Mechanised Weapon Handling Systems

The HMWHS provides mechanical handling facilities for moving palletised munitions around the deep magazine and weapon preparation areas, and a series of weapons lifts to connect the magazines, hangar, weapons preparation area, and flight deck.

The components in question are 56 so-called 'moles', which do the lifting and carrying of the palletised munitions in the magazine. The HMWHS system consists of a network of two versions of these prime movers, which traverse forward and aft (longitudinal, version one) or port and starboard (athwartships, version two), each able to lift and move a payload to locations within its predefined area of travel. The moles can transfer payloads between each other, so the payloads can be located anywhere within the magazine.

The two mole versions are different shapes to enable lifting and lowering of the palletised munitions in the correct orientation, onto the set stowage and transfer positions, and are equipped with electric traverse and lift drives, allowing accurate positional control within the magazine. A number of lifts provide interconnection between the magazines and the hangar, weapons preparation area, and flight deck, and a unique mechanism enables the mole to access the lift platform without needing to disengage and re-engage the pinion from the rack. The magazines are unmanned, with all the moles controlled from a central location, so personnel are required only where munitions are being prepared for storage or use.

A significant challenge in manufacturing the moles has been the achievement of the tight tolerances introduced following completion of the demonstration phase, to speed up assembly.Factory acceptance testing took place at Babcock's site at Whetstone, Leicester, and included dimensional and functional tests and inspections of the parts and mole drive and lifting systems.                                        

The moles have now been delivered to the Aircraft Carrier Alliance's central warehouse, ready for installation once the fixed rail equipment and lifts have been installed. As the moles are fully reassembled, installation will involve placing them in the magazine and electrically connecting them to the rest of the system via an energy chain system. "The moles are a critical component of the HMWHS and successfully completing FATs for all moles marks an important milestone in delivery of the system." 

Babcock Integrated Technology director Matt Hatson comments. "The HMWHS is the first maritime application of shore-based commercial warehousing processes using automated systems with all-electric control, adapted for safe transport and stowage of munitions in a warship environment. Munitions can be delivered, in bulk, to the point of use at rates that could not be achieved manually, whilst minimising the manpower requirement in what is traditionally a labour-intensive process, thus delivering reduced through-life cost, as well as a saving in onboard living accommodation requirements." Production of the final software solution for the HMWHS integrated control system, and manufacture of the various mechanical, electrical, hydraulic and pneumatic sub-systems making up the HMWHS are now underway, of which successful completion of FATs for all moles is part.

The final equipment for the full HMWHS for the first carrier was be delivered by May 2013, and for both vessels by February 2015.Babcock has also been active in working with the shipyards to support the design integration and build strategies. A joint installation strategy has been developed using Babcock's system knowledge and ship build experience, to maximise installation and testing opportunities. Babcock will maintain responsibility for overall installation and quality of work, as well as performing the testing required to demonstrate the system meets ACA requirements. The system in-service support package is being developed with the MoD and Royal Navy.

QE Class Aircraft Carrier Details and Specifications

• Country/Owner/Operator: UK        
• Builders: BAE Systems Surface Ships, Thales Group, Babcock Marine (see below for more details).           
• Cost to Build: £3,5 billion (US$5,520 billion), which is exactly £7 billion for the two carriers of the QE Class by the 2008 contract.           
• Year of service: The end of 2017, fully operational by the end of 2020 (with HMS Prince Of Wales 2  years behind). On HMS QE sea trials to begin 2017, flight trials – 2018.      
• Expected service life of up to 50 years.         
• Homeport: (Her Majesty’s Naval Base) HMNB Portsmouth, one of three UK operating bases for the Royal Navy (along with HMNB Clyde and HMNB Devonport).       
• Capacity/Crew: 1450 (1600 company+aircrew), complement 686+, max 40 aircraft (which is double the existing UK carriers capacity).       
• Length Overall: 932 ft (284 m).       
• Width/Beam: Overall/flight deck 239,4 ft (73 m), waterline 128 ft (39 m).            
• Height: 184 ft (56 m) overall/from keel to masthead.                     
• Weight and Displacement: 65,600 tonnes (64,600 long t) at deep/full load. This is about 3 times the size of the Royal Navy’s current aircraft carriers of the Invincible class. For the construction of the two UK future aircraft carries a total of 80,000 t. of steel is used.
• Top Speed: 25 kn (29 mph or 46 km/h).
• Range: Up to 10,000 nautical miles (19,000 km).

Watch the videos shared in the Recommended Visuals section below for a visual tour of the HMS Queen Elizabeth. LSD

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Article By: Siddhi Indulkar

Recommended Visuals: 1) Video tour of HMS Queen Elizabeth.

                                            2) Time lapse of HMS Queen Elizabeth.

Slow Steaming Strategy

Slow steaming has earned its place as a very commonly used term in the current shipping industry. It is a strategy that shipping companies have on the top of their priority list, and it affects the entire industry, right from the cargo owners to the global supply chain. 

Looking Back

Something happened in the year 2008, that made the entire world think again. Being the major industry that drives the world economy, shipping was supposed to be the pioneer in the thinking process. There was a heavy downturn in the global economy that resulted in reduction in the demand of transportation capacity. Freight rates fell. The worse was still to come. In the years prior to 2008, there was a shipping boom. Order books were full and new ships were on the production line. By the time the record-high deliveries were made, recession hit the industry and new ships were rendered useless. Projects still under development were cancelled. Number of ships sailing the oceans considerably reduced. Idle ships were not the only trouble. There was more. 

The global financial crisis triggered the rise in fuel costs. Higher fuel costs in the time of crisis means diminishing profits and soaring losses for the shipping companies. Operation costs shot up. In short, world trade languished.

The Idea

The major issue that hit the shipping companies was high fuel costs. The only way to tackle the issue was to reduce the consumption of fuel in ships. For that, engines would have to be run on power ranges below their normal operating range. As a result, the speed at which the ships had to sail, were to come down by a few knots. 

You can look at it from the other perspective too. In ships, the power consumed is proportional to the cube of velocity of the ship. So a minute change in a ship's speed can affect the power and fuel consumption to a large extent. (See Figure 1)

Fig. 1: Correlation between ship speed, required engine power and fuel consumption
(Image Courtesy: Wartsila Technical Journal, 2010)

Maersk Line, the world's leading container shipping company used this property of ships to survive through the recession. They reduced their speeds from 27 to 22 knots, that is,  a 19% reduction in speed. That reduced the hourly main engine fuel consumption to 58%. In some cases, further reduction of speeds to 18 knots reduced the fuel oil consumption to 75%. Engines were operating at about 40% of their rated capacities, fuel costs were saved, and Slow Steaming Strategy was born. 

The Domino Effect

The strategy triggered a chain of other factors as soon as it was adopted by Maersk Line. One ton reduction in fuel consumption reduced the carbon dioxide emissions by three tons. Consumption of engine cylinder oil was also reduced nearly by the same percentage, which reduced solid particle emissions. 

But the pioneers had to convince two different sectors which were an integral part of shipping. One, the engine manufacturers, who believed that their engines were not designed to operate efficiently at only 40% of load capacity. Two, their customers, for whom the time of delivery was about to be affected due to slow steaming. 

In 2008, Maersk approached engine manufacturers MAN Diesel and Wartsila to research the effects of engine operations below their design load level (MCR). In late 2008 and early 2009, both the companies published letters of No Objection for low load operations. However, it required extensive maintenance and inspection of machineries onboard.

The other issue with slow steaming was longer time of deliveries, which customers felt, would slacken the global supply chain. Maersk convinced the customers that slow steaming would delay the deliveries, but it would provide more guarantee for safe delivery of goods. This was also offset by another issue. If you remember, due to the recession, more ships remained idle than those which sailed. This was a perfect chance for ship owners to increase their fleet. More ships, low speed, guaranteed safety of goods. And they made a revolutionary strategy out of the global recession. 

Expressed Concerns

Propeller and Engine Efficiency

Marine propellers are designed for an optimum RPM for maximum propulsion efficiency. Slow steaming when incorporated in existing ships, would reduce the RPM levels, therefore decreasing the efficiency of the propeller. Thus it is natural that when the entire main engine and propulsion system is operating at low load levels, the overall system is no longer an optimised one. So the marine engineers and engine builders were initially reluctant to embrace the concept. However, when Wartsila investigated into the matter, what they reported, pushed slow steaming strategy even further. In their reports, they published that their engines could efficiently operate even at low loads up to 10% MCR. It was also discovered that the loss in propeller efficiency was actually offset by the cost savings due to reduced levels of fuel consumption. Some ships also got their propellers replaced to sync with the low load levels. Wartsila and MAN Diesel upgraded their engines to specially designed slow steaming kits. Ships in which, replacements were not done, the engines were to be kept efficient with rigorous maintenance of the main engine and machineries like turbochargers, boilers and blower systems. 

Poor Combustion

Due to low load operation, combustion of fuel in the cylinders is insufficient, resulting in poor atomisation and deposition of soot layer within the cylinder. Regular maintenance is required. Marine engineers are required to clean the cylinder linings before the engines are again fired to full load.

Cold Corrosion 

During slow steaming operation, the engine temperatures are generally lower than what it is designed for optimum performance. As a result, corrosive vapours condense, corroding the interiors. Again, maintenance is the key.

Minor Concerns

Other than the major factors which require regular maintenance for efficient performance, there are few which might affect the performance due to slow steaming practices. In low load operating conditions, the propeller is subjected to low RPM, which increases the probability of propeller blade fouling. Hull fouling probabilities also increase, which require periodic underwater surveys and cleaning. 

Solutions and Acceptance of the Strategy

Inspite of a few issues that popped up during the development of this strategy, it proved to be an overall economic boon to the industry, going by the fuel cost savings. Carbon dioxide emission levels came down, ships that were idle joined the fleet and brought in more revenue even in the years of recession thanks to slow steaming strategy. World's leading manufacturers Wartsila and MAN Diesel joined the initiative and upgraded their engines with special kits designed for slow steaming. Following the success of Maersk Line due to this concept, other shipping companies have adopted the same strategy for efficient shipping. Initially tried on only container ships, now the strategy is being successfully applied to bulkers. That is quite an evidence of the fact that the domino effect is still on.LSD

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Article By: Soumya Chakraborty

Recommended Readings: 

1) Marine Engineer's experience in slow steaming operations.

2) Slow Steaming - A viable option? (By Wartsila)

3) Slow Steaming practices in the global shipping industry. (By MAN Diesel)

An Interview with Dr. Stephen Payne

Dr. Stephen Payne

Dr. Stephen Payne, the Naval Architect and Chief Designer of Queen Mary 2, shot to fame after fulfilling his childhood dream. Stephen was the Vice President and Chief Naval Architect of Carnival Corporate Shipbuilding till 2010 and served the company for 26 years as the designer of many of their ships. He was also the President and Fellow of The Royal Institution of Naval Architects (RINA), UK. 

Stephen was awarded with SNAME Rear Admiral Land Medal, Honorary Doctorate of Science University of Southampton, Officer of the Most Excellent Order of the British Empire OBE, Merchant Navy Medal MNM, Solent EBP Amazing Person Award, and many others. In 2011, he founded PFJ Maritime Consulting Limited and is presently the Founding Partner of the firm. He also likes to involve himself in interaction with students and after-dinner talks at various youth forums. 

In his interview with us, Stephen shared his experience in designing the Queen Mary 2, and his predictions on the future of the shipping industry. Not only that; he had some message for the youth too!

What was the biggest obstacle during the design of The Queen Mary 2? How did you overcome it?

The biggest obstacle was convincing everybody that for transatlantic service a true liner was needed and not just a cruise ship that looked like a liner. The problem was that from moving from a cruise ship to a liner entailed a 40% premium because of the extra power, strength, sea margin and shape considerations. I overcame this through maximising the number of balcony cabins by moving the main public rooms low down in the ship to provide sufficient height for the first passenger cabin deck to be a balcony deck with high revenue cabins.

For the last five years, the graphs of the maritime industry have seen a negative slope. In such scenarios, what qualities do ship design and shipbuilding companies look for, in Naval Architecture graduates? What are the talents that the industry is yet in need of?

The shipping companies, classification societies and shipyards are all looking for graduates that have a grasp of the fundamentals of efficient design with a flair for innovation and thinking outside the box. Everyone is looking at fuel economy from propulsive efficiency and auxiliary load. This will become even more acute as new environmental regulations on NOx and SOx begin to bite and owners have to either switch to more refined and expensive fuels or invest in scrubbing technology or future viable alternatives.

What do you think, is the scope of entrepreneurship for Naval Architects? 

I think the scope for entrepreneurship within naval architecture is vast. You only have to look at recent advances such as air-injection for hull lubrication to realise the scope for future innovation and entrepreneurship is boundless.

From the time you set foot into the ship design and building industry, to now; how has the industry changed in these years? And what changes do you predict in the recent future?

With regards passenger ship design, the biggest change I believe is the proliferation of balcony cabins which began with the introduction of Royal Princess in 1984. Her unique all outside/all balcony design set new standards which has been emulated ever since. The diesel has supplanted steam propulsion across almost all commercial shipping, either with direct drive, geared drive or with electric drive. The gas turbine showed some promise with its incredible power density but the high price of its fuel has seen it decline in recent years. However, the new environmental regulations mentioned earlier may see the turbines show some advantage. The immediate future heralds the potential of LNG but the future must inevitably point towards a compact marinised nuclear reactor –but that’s some way off, not because the technology doesn't exist, but public perception is generally negative at this time. As fossil fuel become scarcer in the future, nuclear will have to be considered as an option. As for the marine industry as a whole, when I joined it in 1985 there was still very much of a “family business” attitude. Sadly, this has largely disappeared as the smaller companies have been absorbed into huge corporations. Business has become more cut-throat and impersonal –but perhaps that’s the price of progress!

What percentage of designers of the Queen Mary 2 were from the younger age group? Did that percent of youth play an important role in the design?

I was 37 when I received the commission to design Queen Mary 2. The marine engineer on the project was somewhat younger, as was the electronics engineer. The structural engineer and safety specialists on the team were of comparable age to me and it was only the two electrical engineers that were older, both being in their fifties and sixties. So, we were a relatively young team that worked well together. Many of the shipyard engineers were relatively young as well.

If there was a debate on Naval Architecture being an Art or a Science, which side would you speak for? And why?

My marine engineering colleagues have always asserted that naval architecture is a “black art”! Whereas Art can be abstract, Science can be defined as a branch of study, concerned with facts, principles and methods. I am therefore firmly in the camp that sees naval architecture as a “Science”! To be successful, a ship has to be designed according to known principles –there’s no room for art when dealing with issues such as stability!

Deep Sea Risers

Technological advances have created economically viable solutions to the complications of well-control methods that are created by subsea blowout preventer systems. Further, wells are being drilled in waters deeper than before, and subsea technology has made it possible. Innovations have led to the invention of different types of Marine Riser Systems(Deep Sea Riser).

How Do Risers Work?

They transfer the materials from sea floor to production and drilling facilities atop the water's surface, as well as from the facility to the seafloor. Subsea risers are a type of pipeline developed for this type of vertical transportation. Whether serving as production or import/export vehicles, risers are the connection between the subsea field developments and production and drilling facilities.

Similar to pipelines or flowlines, risers transport produced hydrocarbons, as well as production materials, such as injection fluids, control fluids and gas lift. Usually insulated to withstand seafloor temperatures, riser can be either rigid or flexible.

The following video gives us a rough idea about Marine Riser System, later in the article the different types of risers are explained.
                   
                            

Types of Risers

There are a number of types of risers, including attached riser, pull tube risers, steel catenary risers, top-tensioned risers, risers towers and flexible riser configurations, as well as drilling risers.

Steel catenary risers

Build on catenary equation that has helped to create bridges around the world. Used for connecting the sea floors to the floating facilities above,as well as connect two floating platforms together. These are common on TLP's, spars & FPSO's, as well as fixed structures, compliant towers & gravity structures. While this curved riser can withstand some motion, excessive movement can cause problems.

Fig. 1: Steel catenary riser
(Image Courtesy: Google Images)

Attached risers

 They are developed on fixed platforms, compliant towers and concrete gravity structures. They are clamped to the side of the fixed facilities, connecting the seabed to the production facility above. Usually fabricated in sections, the riser section closest to the seafloor is joined with a flowline or export pipeline, and clamped to the side of the facility, until the top riser section is joined with the processing equipment atop the facility.

Top-tensioned risers

Used on TLP's and spars. These are completely vertical riser system that terminates directly below the facility. Although moored, these floating facilities are able to move laterally with the winds & waves. Because the rigid risers are also fixed to the sea floor, vertical displacement occurs between between the top of the riser and its connection point on the facility. There are two solutions for this issue. A motion compensator can be included in the top tensioning riser system that keeps constant tension on the riser by expanding and contacting with the movements of the facility. Also, buoyancy cans, can be deployed around the outside of the riser to keep it afloat. Then the top of the rigid vertical top-tensioned riser is connected to the facility by flexible pipe, which is better able to accommodate the movements of the facility. 

Fig. 2:  Top-tensioned riser
(Image Courtesy: Google Images)

Pull tube risers

These are pipelines threaded up the center of the facility. For pull tube riser, a pull tube with a diameter wider than the riser is preinstalled on the facility. Then, a wire is attached to the pipeline or flowline on the seafloor. The line is then pulled through the pull tube to the topsides, bringing the pipe along with it.

Riser Towers

Ideal for ultra-Deep water environments, this riser design incorporates a steel column tower that reaches almost to the surface of the water, and this tower is topped with a massive buoyancy tank. The risers are located inside the tower, spanning the distance from the seafloor to the top of the tower and the buoyancy tanks. The buoyancy of the tanks keeps the risers tensioned in place. Flexible risers are then converted to the vertical risers and ultimately to the facility above.

Fig. 3:  Riser Tower
(Image Courtesy: Google Images)

Flexible risers

A hybrid that can accommodate a number of different situations. It can withstand both vertical and horizontal movement, making them ideal for use with floating facilities. This flexible pipe was originally used to connect production equipment aboard a floating facility to production and export risers, but now it is found as a primary riser solution as well. There area number of configurations for flexible risers, including the steep S and lazy S that utilize anchored buoyancy modules, as well as steep wave and lazy wave that incorporates buoyancy modules.

Fig. 4:  Flexible riser(Image Courtesy: Google Images)

Drilling risers

These transfer mud to the surface during drilling activities. Connected to the subsea BOP(blowout preventer) stack at the bottom and the rig at the top, drilling risers temporarily connect the well bore to the surface to ensure drilling fluids to not leak into the water.LSD

Fig. 5:  Drilling riser
(Image Courtesy: Google Images)

Article By: Tanumoy Sinha

Recommended Readings: Riser Technology, Rigzone training

E-Ship 1: Magnus Sailing

Today's shipping industry contributes to about 5% of total carbon dioxide emission and the GHG emissions have shot up to 2.7% according to the studies conducted by International Maritime Organization. Oil prices have frenetically hit the ceiling with increment rates almost three times higher than those of the nineties. In such a scenario, the stratagem of ship designers has been to attain the optimum benchmark between prevailing fuel economy and environmental safety standards. Visions have shifted towards unconventional propulsion systems and use of renewable resources of energy is rapidly burgeoning. 

Realizing this, Enercon, with its 20 years experience in wind power engineering, has taken one of the most innovative steps in the design of its wind turbine carrier, E SHIP 1. The fact that it is designed to carry offshore wind turbines to their sites, is just like another story. But what will probably baffle you is that they have used the same physics to propel the ship, that a footballer uses while doing the banana free kicks! (Watch video) It is called the Magnus Effect. To understand this effect, imagine a fluid medium (like water or wind) moving at some velocity in some direction. Now let's place a stationary cylinder or a ball (let's take a cylinder here) in the medium and mechanically induce a rotation in the cylinder about its axis. Now refer to Figure 1. and tally what you're going to read.

Fig. 1: The Magnus Effect
(Image Courtesy: Google Images)

The fluid will obviously pass around the boundary of the cylinder, but note the difference in the pattern of flow on both the sides of the cylinder. On the top side (as per the figure) the velocity of the cylinder opposes the fluid velocity (thanks to friction) therefore reducing the net fluid velocity on this side. Recall the famous Bernoulli's Equation, and you'll feel the pressure on this side increasing. On the lower side, the scenario is very much the opposite. Supported by the direction of rotation of cylinder, the fluid on this side has an increased velocity and therefore, reduced pressure. The pressure difference between the two sides of the cylinder results in a force that is vectored along the direction shown (from high pressure to low pressure), which now induces in the stationary cylinder, a translation motion along its direction. This effect is used to swing the balls in football, cricket, golf, tennis, table tennis and baseball. Now take a look at Figure 2 and we'll soon see how the designers used a 90 year old technology that was rejected long time back, to slice through fuel price issues.

Fig. 2: The ENERCON E-SHIP 1
(Image Courtesy: Google Images)

The 90-Years Old Rejected Technology

The ship is powered by a diesel electric propulsion system consisting of one Controllable Pitch Propeller and three rudders. But what is remarkable in the ship, is the set of four vertical cylindrical structures on the main deck. They, in operation along with the diesel-electric propulsion system actually help the ship save about 20% of its fuel consumption when there are beam winds, also reducing the load on the propeller.  And they do that exactly by the principle of Magnus Effect. When there is a beam wind, these cylinders are rotated about their axis by an electric drive so as to direct the resultant magnus force along the direction of required surge.The concept of these cylinders were developed by Anton Flettener, and hence received the name: Flettener Rotors. The direction and speed of rotation of all the four are automatically set by the electronic wind sensing and control system, which involves less crew work as in case of sail powered propulsion, also leaving less room for human errors. The vectorial representation of this is as shown in Figure 3.

Fig. 3: Magnus effect applied to a ship
(Image Courtesy: Enercon)

The Question You Missed

These flettener rotors are rotated by means of an electric drive. So the obvious question is, Why spend that energy on electricity when it could have been spent on the conventional diesel-electric propulsion system? This obviously seems like a paradox, as in, we are just reducing consumption of diesel and ending up generation some extra electric energy which would power rotors that finally use the wind energy. We have seen the fuel consumption drop by 20% when the rotors are used along with the diesel-electric drive. But have we dropped the total energy consumption? The answer is Yes. The hot exhaust fumes of the diesel engines that power the conventional propulsion don't go waste. They are led to run a Siemens steam turbine that generates the electricity used to spin the flettener rotor sails. Figure 4 shows the CFD estimated power savings with varying directions of wind (24 knots / 6 Beaufort Scale) at the design speed of 16 knots. The yellow dot shows the attained savings at the trials, which was successfully above the estimated levels.

Fig. 4: Power Saving (%) vs. Wind Direction
(Image Courtesy: Enercon)

The Green Hull

Enercon seems to have left no stones unturned to optimise the ship for minimum environmental effects. With a 20 year global experience in wind power engineering, they designed the hull of E-Ship 1 to aerodynamically offer less resistance, therefore cutting fuel consumption even more. Also, to protect the for'd placed superstructure from green waters in rough seas, the wave breaker was developed and tested. The resistance of the ship was further decreased by using a low-resistance hull coating below the waterline. 

Fig. 5: The break water in front of the superstructure

Oh, and one more fun fact: She uses her hear from the engines to cool her interiors. In case, you know, 20% wasn't much of a reduction to set new standards. LSD

Article By: Soumya Chakraborty

Recommended Readings: Dynamic performance of Flettner rotors with and without Thom discs. (University of Manchester, UK)