Mechanical Energy Storage

By Keith Henderson at August 17, 2010 09:51
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International combustion and engineering consultants Ricardo has been actively developing hybrid propulsion systems with mechanical and electrical energy storage and fuel cell systems. Ricardo believe that advanced propulsion systems can achieve fuel consumption savings between 15 and 25 percent within existing and planned international emissions regulations by implementing next generation energy management and propulsion technologies. To investigate this further, Ricardo has formed a project called the Ship Efficiency & Energy Storage Assessment consortium (SeEsA), covering energy management of propulsion and auxiliary power systems. An early project focus will be on assessing the best energy storage solutions. Under consideration will be conventional, state-of-the art battery and flywheel based systems of which Ricardo has built up considerable expertise in kinetic energy recovery systems (KERS). Their flywheel energy storage system concept called Kinergy, uses a magnetic gearing and coupling mechanism. An automotive project using a mechanical energy storage system has shown to offer several advantages over a battery based electric hybrid system.
The international combustion and engineering consultants Ricardo has been actively involved for a number of years in development of hybrid propulsion systems, including mechanical and electrical energy storage, and fuel cell systems for a number of international clients as well as their own technology research program.

Using a careful selection of well proven propulsion, energy storage, after-treatment and waste heat recovery solutions, Ricardo believe that advanced propulsion systems can achieve real fuel consumption savings within existing and planned international emissions regulations. Implementing next generation energy management and propulsion technologies, realistic fuel consumption reductions of between 15 and 25 percent will be possible compared with conventional existing marine propulsion configurations.

To investigate this further, including practical implications, Ricardo has formed a project called the Ship Efficiency & Energy Storage Assessment consortium (SeEsA), covering energy management of propulsion and auxiliary power systems.

Early in the project, focus will be on assessing the best energy storage solution combined with advanced energy recovery systems for a complete propulsion system under different operating conditions including normal operation, slow steaming and up to three additional duty cycles.

The different types of energy storage systems under consideration will include conventional, state-of-the art battery and flywheel based systems. Regarding the latter, Ricardo has built up considerable expertise including the engineering of kinetic energy recovery systems (KERS) for motor sport (Formula 1). Their high speed, hermetically sealed flywheel energy storage system concept called Kinergy, uses an innovative and patented magnetic gearing and coupling mechanism.

Whilst electric hybrid systems using chemical batteries are already in use for a variety of applications these configurations add considerable weight and complexity, incur repeating costs due to regular battery replacement and are associated with other environmental / disposal issues. In an automotive project, mechanical energy storage systems have been shown to offer up to twice the efficiency of a battery based electric hybrid system in a package that is half the size, half the weight and a quarter of the cost. We hope that marine applications for this technology can be successfully developed and will be able to deliver similar benefits at a future date.
 
 

Exhaust Gas Scrubbers

By Keith Henderson at August 16, 2010 08:29
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The expansion of Emission Control Areas (ECA) in North American and European waters leaves ship owners using HFO with little choice other than to use a more expensive low sulfur HFO, change to MDO completely or use a dual fuel arrangement. The latter not only necessitates installing additional tanks and fuel handling equipment but also requires careful change over procedures to be followed every single time to avoid potential engine problems that can be very severe. An area that a few operators are pioneering is the use of exhaust seawater scrubbers. Hamworthy Krystallon produce a Seawater Scrubber that is designed to operate on a 3.5 per cent S HFO 380 fuel while complying with the EU in-port and MARPOL Annex VI requirement of a 0.1 per cent sulfur fuel. Hamworthy Krystallon early orders from Italian owner have been followed this month by an order to equip four 45,000 dwt ro-ro new builds at Daewoo. Sembawang Shipyard (SSPL), Singapore are interested in a potential retrofit project for seawater scrubbers. Switching to low sulfur fuels will create supply problems according to he International Petroleum Industry Environmental Conservation Association
The expansion of Emission Control Areas (ECA) in North American and European waters leaves ship owners using HFO with little choice other than to use a more expensive low sulfur HFO, change to MDO completely or use a dual fuel arrangement. The latter not only necessitates installing additional tanks and fuel handling equipment but also requires careful change over procedures to be followed every single time to avoid potential engine problems that can be very severe.

An area of interest that a few operators are pioneering is the use of exhaust abatement technology in the form of seawater scrubbers. Hamworthy Krystallon produce a Seawater Scrubber that is designed to remove 99 per cent of SOx and 80 per cent of particulates when operated on a 3.5 per cent S HFO 380 fuel thus complying with the EU in-port and MARPOL Annex VI requirement of a 0.1 per cent sulfur fuel. It also reduces exhaust noise and typically fits around the funnel space being both lightweight and self supporting.

Trials have been running on the P&O Ferries Pride of Kent with a 1MW auxiliary gen set and with an 8 MW auxiliary gen set on board the Holland America Lines cruise ship. Hamworthy Krystallon early orders from Italian owner Ignazio & C have been followed this month by an order to equip four 45,000 dwt ro-ro new builds at Daewoo. It allows the ships to use high sulfur HFO in port yet be within the EU directive requiring sulfur emissions equivalent to just 0.1 per cent fuel-sulfur content. Sembawang Shipyard (SSPL), Singapore are interested in a potential retrofit project for seawater scrubbers.

Switching to low sulfur fuels has other problems as the International Petroleum Industry Environmental Conservation Association said recently, producing enough low sulfur content distillates to meet the IMO 2015 target on main engines would be “difficult” and “significantly more expensive”. Meeting later targets would need “major refinery investment” and may “not be economically feasible”. This suggests price increases are to be expected!

 
 

Why do people make mistakes?

By Keith Henderson at August 04, 2010 15:53
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Mistakes cause accidents. That is the inevitable sequence of events and we humans are the people making the mistakes, but why? What are the reasons that people make mistakes? NK’s guidelines covers how to prevent them, it focused mainly on design of equipment and operator training. Why people make mistakes? - some opinions and answers were given during the June 2010 Members Day of the marine insurance organization Swedish Club. Firstly the world crew shortage estimated at 50,000 seafarers isn’t helping the industry. Good relations, communication and training are conducive to people making the right decisions yet having the confidence to challenge questionable decisions. Capt Gustav Groenberg of Star Cruises, Malaysia pointed out the importance of recruiting the right people, offering them good working conditions to motivate and retain them. Peter Groenwoldt, MD of Harren & Partner Ship Management, Bremen’s opinion is that the reason for a mistake is always, without exception, human error caused by: lack of or poor training, ignorance or an over estimation of their skill and experience. Martin Hernqvist, MD of the Swedish Club Academy touched on the sensitive issue of culture on the individual’s ability to challenge mistakes and unsafe acts quoting the Power Distance Index as a measure of different cultures and their behavior.
Mistakes cause accidents. That is the inevitable sequence of events and we humans are the people making the mistakes, but why? What are the reasons that people make mistakes? Following on from my earlier blog on accidents and NK’s guidelines how to prevent them, it focused mainly on design of equipment and operator training. This blog looks into the subject of why people make mistakes? Some opinions and answers were given during the June 2010 Members Day of the marine insurance organization Swedish Club.

Firstly the world crew shortage estimated at 50,000 seafarers isn’t helping the industry. Good relations, communication and training are conducive to people making the right decisions yet having the confidence to challenge questionable decisions. One of the four panelists Rob Grool, MD of Wallem Shipmanagement, Hong Kong said that , “crews must feel that they can always call for help and the only stupid questions is the one you dare not ask!”

Capt Gustav Groenberg of Star Cruises, Malaysia pointed out the importance of recruiting the right people, offering them good working conditions to motivate and retain them. “A high staff turnover is a serious threat to safety,” he said. Commenting on the lower casualties involving cruise ships he said, “many cruise companies have adopted the pilot co-pilot system for their bridge operations and have implemented Standard Operating Procedures that are designed to reduce the risk of a ‘one person error’ accident. These SOPs have been developed to detect and trap an error before it leads to serious consequences. Errors are acceptable but negligence or carelessness is not!”

Peter Groenwoldt, MD of Harren & Partner Ship Management, Bremen is in no doubt as to why people make mistakes. His opinion is that the reason for a mistake is always, without exception, human error caused by one of the three reasons: lack of or poor training, ignorance or an over estimation of their skill and experience. He continued, “we see too many crew members who obviously got their licenses and certificates under the Christmas tree ….. and who pass medical examinations (when) seriously ill (yet are) testified fit for service.

Martin Hernqvist, MD of the Swedish Club Academy touched on the sensitive issue of the influence of culture on the individual’s ability to challenge mistakes and unsafe acts quoting the Power Distance Index as a measure of different cultures and their behavior.
Following a question and answer session the meeting was closed by Lars Rhodin, MD of the Swedish Club.
 
 

Human Error & Accidents

By Keith Henderson at August 04, 2010 08:03
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The Japanese classification society NK published a 42 page booklet titled “Guidelines for the Prevention of Human Error Aboard Ships”, with the sub heading “Through the Ergonomic Design of Marine Machinery Systems.” According to the guidelines, man-made causes are said to account for 80 per cent of all marine accidents. The guidelines stress the importance of standardization in operating, control, methods, indicators, labeling and color coding to reduce confusion, avoiding the situation when crews familiar with a procedure on one ship are faced with opposites in procedure on another ship. To this end ergonomic design plays an important part so that operation of equipment is easy to understand and logical (even though logic differs by culture). A chapter covers design considerations and recommendations and there is an interesting section titled countermeasures giving advice on risk assessment and the best course of action to prevent (re-) occurrence. The publication includes a number of detailed reports of marine accidents and how to prevent their recurrence.
The Japanese classification society NK published earlier this year a 42 page booklet titled “Guidelines for the Prevention of Human Error Aboard Ships”, with the sub heading “Through the Ergonomic Design of Marine Machinery Systems.” According to the guidelines, man-made causes are said to account for 80 per cent of all marine accidents. Despite training and instruction of crew members accidents occur that are attributable to confusion or ignorance in the operation of equipment. The guidelines stress the importance of standardization in operating, control, methods, indicators, labeling and color coding to reduce confusion, avoiding the situation when crews familiar with a procedure on one ship are faced with opposites in procedure on another ship. To this end ergonomic design plays an important part so that operation of equipment is easy to understand and logical (even though logic differs by culture).

A chapter covers design considerations and recommendations to prevent human error, explaining causes and giving advice on information displays, prevention of wrong operation, improvements in operability and working environment. An interesting section titled countermeasures gives advice on risk assessment and how to analyze accidents and malfunctions to determine the best course of action to remedy the cause depending on the severity and (re-)occurrence.
To illustrate practical aspects of the guidelines, the publication includes a number of detailed reports of marine accidents, ranging from a broken gen set con-rod to falls with fatal consequences. Their cause is identified and showing how changes could be made to prevent their recurrence. Good reading for anyone concerned with ship design or operation.
 
 

Propulsion Efficiency

By Keith Henderson at July 21, 2010 08:22
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This June the Finnish based Eniram company from Helsinki, was selected as a finalist of an award for emerging European technology companies Eniram provide a number of products for on board and ashore monitoring of ship performance offering real time solutions. A product gaining wider acceptance for owners and operators of cruise ships, large freight vessels and tankers is their Dynamic Trimming Assistant (DTA). A number of data sensors, with software analyzing the ship’s trim, helps vessel crews optimize trim at all times, by presenting the solution in an easy to understand graphical display. DTA does this by balancing inter related variables such as minimizing water resistance, decreasing fuel consumption, use of stabilizers and reducing emissions. External items such as waves, wind and speed are also included in the analysis. In practice, this means startling savings may be achieved. Several fleet operators are using DTA including Royal Caribbean Lines and the Hamburg Sud Group. A separate but not unrelated product, is Hull Fouling Analysis used to optimize the maintenance and efficient operation of the submerged ship’s hull area.

The European Tech Tour Association is an independent non-profit organization committed to the development of emerging European technology companies covering a wide number of applications. This June the Finnish based Eniram company from Helsinki was selected to be one of 30 finalists.

Eniram provide a number of products for on board and ashore monitoring of ship performance offering real time solutions. A product gaining wider acceptance for owners and operators of cruise ships, large freight vessels and tankers is their Dynamic Trimming Assistant (DTA). A number of data sensors, with software analyzing the ship’s trim, helps vessel crews optimize trim at all times, by presenting the solution in an easy to understand graphical display. DTA does this by balancing inter related variables such as minimizing water resistance, decreasing fuel consumption, use of stabilizers and reducing emissions. External items such as waves, wind and speed are also included in the analysis.

In practice, this means startling savings may be achieved. Several fleet operators are using DTA including the Oasis of the Seas and six other Royal Caribbean ships. Following a test period on the 5,500 TEU container ship Alianca Maua, where fuel savings of between three to five per cent were reported, the Hamburg Sud Group announced in April that 26 vessels are to be equipped with DTA.

A separate but not unrelated product, is Hull Fouling Analysis used to optimize the maintenance and efficient operation of the submerged ship’s hull area. Monitoring draft variations and the effect of changes in the hull, it provides a means to optimize the cleaning costs and keep fuel waste due to fouling to a minimum.


 

Hydrogen Tug

By Keith Henderson at July 18, 2010 05:41
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At the recent International Tug & Salvage Conference in Vancouver details of a new hybrid tug was presented with the triple propulsion modes of diesel electric, battery and fuel cell claiming to give a 67 per cent emission savings over conventional diesel operation. Aim of this particular Hybrid Electric Tug design is to provide an operating mode of zero emissions for the majority of the tug's duty profile during low power operation up to 35 per cent of full power: this includes transits at a cruising speed of about nine knots. Based on a current conventional 24-m hull design developed by Capilano Maritime Design Ltd. with 55-tonne bollard pull, a more powerful 70-tonnes bollard pull version would only require minor changes to the hull and propulsion drives with an increase in battery capacity with diesel generator and fuel cell systems remaining unchanged. Four fuel cells of the PEM type are specified giving a total continuous power output of 600kWe, representing 17 per cent of power. There is a 1,000 kW-h capacity Li-Ion battery system which allows a combined power output of 1,250 kWe. A storage capacity of 1,200 kg of hydrogen provides an endurance of about 40 hours at full power, sufficient to allow refueling intervals of about once per week.
At the recent International Tug & Salvage Conference in Vancouver details of a new hybrid tug was  presented with the triple propulsion modes of diesel electric, battery and fuel cell claiming to give a 67 per cent emission savings over conventional diesel operation. The usage profile of harbour / ship docking tugs is an ideal candidate for hybrid applications as the main diesel engines are not needed for 80 per cent of the time.

The aim of this particular Hybrid Electric Tug design is to provide an operating mode of zero emissions for the majority of the tug's duty profile during low power operation up to 35 per cent of full power: this  includes transits at a cruising speed of about nine (9) knots.

The proposed vessel is based on a current conventional 24-m hull design developed by Capilano
Maritime Design Ltd. with 55-tonne bollard pull, capable of  handling most ship-docking duties in a modern harbor.  A more powerful 70-tonnes bollard pull version would only require minor changes to the hull and propulsion drives with an increase in battery capacity. The diesel generator and fuel cell systems could remain the same.

Four fuel cells of the PEM type are specified giving a total continuous power output of 600kWe, representing 17 per cent of power. Although the fuel cells are conservatively rated at 150 kWe, practice shows that where fuel cells are employed in a hybrid combination with batteries in a marine application with excellent seawater cooling,  the maximum rating may be increased to nearly 200 kWe.

There is a 1,000 kW-h capacity Li-Ion battery system which allows a combined power output of 1,250 kWe, or 35 per cent of power for more than one hour. A major benefit of the large capacity battery system is that it permits onboard storage of usually less expensive energy purchased from a shore power supply.

A storage capacity of 1,200 kg of hydrogen was specified to provide an endurance of about 40 hours at full power, sufficient to allow refuelling intervals of about once per week.

The capital cost for a conventional tug is approximately $12M, in comparison the cost of this proposed   vessel is $23-25M, however if several are built the cost could be expected to reduced to $16-18M due to a significant price reduction of the fuel cells and advanced batteries.

On the question of  life cycle costs, it is estimated that the Hybrid Electric Tug will be lower, depending on future rates for diesel fuel and shore power.

Frisian Solar Challenge

By Keith Henderson at July 12, 2010 05:48
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Last week the Third Frisian Solar Challenge took place in the Netherlands with the competitors covering a 137 mile (220 km) course over a six day period. There were a total of 40 teams comprising mainly technical colleges and universities from eight countries with the furthest one coming from Brazil. The solar boat race is divided into three classes: class A class for one-person boats, class B class for two-person boats, and the open or Top class C may have a crew of any size. To keep costs down, entries in the A and B classes are loaned solar panels, the Top class is free to use as many panels as they wish limited in practice to the vessel’s overall dimensions and a max power limit of 1750W. On board battery storage with a maximum capacity of 1kWh is permitted. The overall winner of class A was Team Sunrise (Netherlands) completing the course in 16hrs 06 mins at an average speed of 8.5mph, class B Energa Solar II (Poland) in 19hrs 25mins with an average of 7 mph and Top class Private Energy Solarboatteam (Netherlands) in 11hrs 26mins averaging 12 mph
Last week the Third Frisian Solar Challenge, (subtitled  the World Cup for Solar Powered Boats), took place in the Netherlands and was fortunate to have enjoyed near tropical weather throughout the whole week. The prolonged sunlight had a “supercharged” effect as the solar boats covered the 137 mile (220 km) course over a six day period.
The race starts and ends in Leeuwarden, the capital of the northerly province of Friesland, and follows the route of the classic Eleven City Tour winter skating competition of canals, rivers, and lakes through Friesland.
Truly international in nature, this year there was a total of 40 teams comprising mainly of technical colleges and universities competing from eight countries with the furthest one coming from Brazil.
The solar boat race is divided into three classes: class A class for one-person boats, class B class for two-person boats, and the open or Top class C may have a crew of any size.
To keep costs down, entries in the A and B classes are loaned solar panels by the race's sponsors Sharp and The Sun Factory. Class A boats receive five panels, class B six panels each with an output of 175W. The Top class is free to use as many panels as they wish however are limited in practice due to the vessel’s overall dimensions and a max power limit of 1750W. On board battery storage with a maximum capacity of 1kWh is permitted.
The overall winner of class A was Team Sunrise (Netherlands) completing the course in 16hrs 06 mins at an average speed of 8.5mph, class B Energa Solar II (Poland) in 19hrs 25mins with an average of 7 mph and Top class Private Energy Solarboatteam (Netherlands) in 11hrs 26mins averaging 12 mph.
Most if not all the hulls are carbon fiber and some boats have a top speed over 15 mph. With the long hours of daylight and the short duration of each leg of the race (about six hours per day) there is ample time to recharge the batteries using the only permitted method – the solar panels. Key to winning the race seems to be an electronic propulsion management system to balance the boat speed, battery energy level and solar panel power. The winning boat in class A has made this an exact science and crossed the finishing line with only one per cent of battery power left!
 
 

Opposed-Piston Opposed-Cylinder Engine.

By Keith Henderson at July 11, 2010 07:01
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It’s not often that we hear of a new type of piston engine that claims to be lighter, more powerful, less emissions and more efficient that the engines we have today, added to this is the capability to operate on a variety of fuels. Its design combines features of the Jumo J205 diesel aircraft engine and the venerable Volkswagen boxer engine. The inventor of this new engine is Prof Peter Hofbauer, former Director of Engine Development at Volkswagen Group, and later with the company developing the engine EcoMotors, established in early 2008. The engine is a turbocharged two stroke Opposed Piston Opposed Cylinder engine (OPOC) and as a high speed engine has automotive, marine, agricultural, stationary and generator applications. It has only one crankshaft and the opposed pistons are moved by rods attached to the single crankshaft. One cylinder module comprises of two opposed cylinders and the concept allows engines of greater power to be produced by adding more modules. The largest version of the OPOC engine module so far, has a cylinder bore of 100mm yet produces 325hp at 3,500rpm for a weight of under 300 lbs giving a power to weight ration of 1.1 hp per lb. Sluggishness in acceleration due to turbocharger lag is eliminated by the novel use of an electric motor used to spin up the turbo when the throttle is cracked open – a supercharger in effect.
It’s not often that we hear of a new type of piston engine that claims to be lighter, more powerful, less emissions and more efficient that the engines we have today. Added to this is the capability to operate on a variety of fuels including, diesel, JP8, ethanol, gasoline, natural gas, and hydrogen and has a very substantial weight saving. To be fair, its design combines features of previous remarkable pre World War 2 engine designs as the Jumo J205 diesel aircraft engine developed by Hugo Junkers and Ferdinand Porsche’s venerable Volkswagen boxer engine.

The inventor of this new engine is Prof Peter Hofbauer a former Director of Engine Development at the Volkswagen Group developing VW and Audi diesel engines and later was with the engine research organization FEV. Later he joined the company developing the engine, EcoMotors, established in early 2008.

The engine is a turbocharged two stroke Opposed Piston Opposed Cylinder engine (OPOC) and as a high speed engine has automotive, marine, agricultural, stationary and generator applications. It has only one crankshaft and the opposed pistons are moved by rods attached to the single crankshaft: in this respect it is unlike other opposed piston engines such as the Fairbanks Morse or Jumo/Duxford designs.

One cylinder module comprises of two opposed cylinders and the concept allows engines of greater power to be produced by adding more modules. The largest version of the OPOC engine module so far, has a cylinder bore of 100mm yet produces 325hp at 3,500rpm for a weight of under 300 lbs giving a power to weight ration of 1.1 hp per lb.

Sluggishness in acceleration due to turbocharger lag is eliminated by the novel use of an electric motor used to spin up the turbo when the throttle is cracked open – a supercharger in effect. At constant load the electric motor is not used and the turbo is driven purely by the exhaust gases.

As the challenge of meeting ever stricter emission regulations increases, perhaps the OPOC which at present focuses on automotive applications may provide solutions in the future for marine use.
 
 

Propeller shaft enclosure system

By Keith Henderson at July 09, 2010 16:34
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There is a patented device claiming to give between 6 to 10 per cent increased efficiency to the propulsion system applying mainly to planning hulls with inboards. The BOSS (Bolt On Shaft System) as it is called, basically is a tube that encloses the immersed part of the propeller shaft and combines it with a seal and thrust bearing that is mounted directly on to the hull. The self contained unit eliminates through hull sealing and alignment difficulties, and allows the gearbox and engine to be mounted free of thrust considerations. The propeller end of the tube is supported by a P-bracket type of arrangement. For the boat builder, installation times are substantially reduced and the built-in watertight shaft seal ensures a dry bilge. For the user, the reduced losses give the benefits of lower fuel consumption, improved range or a higher top speed. It’s available for shaft diameters of one to four inches (25 – 102mm) and is claimed to lower propulsion noise and vibration.
At one of the trade shows I was visiting there was a patented device claiming to give between 6 to 10 per cent increased efficiency to the propulsion system. It mainly applies to planning hulls with inboards but when one looks at all the patrol boats and various, not to mention recreational craft it does offer substantial savings to a very large worldwide market.

The BOSS (Bolt On Shaft System) as it is called, basically is a tube that encloses the immersed part of the propeller shaft and combines it with a seal and thrust bearing that is mounted directly on to the hull. The self contained unit eliminates through hull sealing and alignment difficulties, and allows the gearbox and engine to be mounted free of thrust considerations. Between shaft and tube there is oil thereby eliminating shaft corrosion and the necessity of shaft mounted sacrificial anodes. The propeller end of the tube is supported by a P-bracket type of arrangement.

In an unenclosed system a propeller shaft rotating in a fluid creates a force perpendicular to the direction of motion. This is known as the Magnus effect and absorbs energy causing losses: in the BOSS system these losses are not created.

For the boat builder, installation times are substantially reduced and the built-in watertight shaft seal ensures a dry bilge. For the user, the reduced losses give the benefits of lower fuel consumption, improved range or a higher top speed.

It is available for shaft diameters of one to four inches (25 – 102mm) and is claimed to lower propulsion noise and vibration.

ShipArrestor Project

By Keith Henderson at July 08, 2010 06:30
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Last month a system called ShipArrestor was tested by consortium leader Miko Marine AS, Norway as part of a two year EU funded program started in Oct 2008 to try to develop a system to prevent such disasters. In the 1990’s there was a Norwegian project called NepCon which researched possible ways to bring a stricken ship under control. It was impractical for a number of reasons but mainly because ropes chaffed and when substituted with chain of sufficient strength. it was too heavy for the helicopter to lift it! Under the ShipArrestor program a special steel chain is used that is lighter than the proposed titanium chain. So the helicopter can drop the lasso over the windlass is achieved by putting the chain inside an inflatable collar of about 6m diameter. Once the windlass is ringed, a 30m diameter sea anchor can be deployed to bring the bow round, reduce roll and slow the drifting until a tug can commence towing. In June 2010, the complete ShipArrestor system was tested and was considered a major success in proving its functionality and practicability, however the calm weather conditions were too good to give any definite indication as to how the system would behave in a real life situation. Further tests will be made: the program is due to run to September 2010.
We have all seen the desperate situation of a disabled or abandoned ship drifting helplessly toward a lee shore and about to founder with devastating if not catastrophic consequences. Last month a system called ShipArrestor was tested by consortium leader Miko Marine AS, Norway as part of a two year EU funded program started in Oct 2008 to try to develop a system to prevent such disasters.

In the 1990’s there was a Norwegian project called NepCon which researched possible ways to bring a stricken ship under control. A technique was investigated to lasso the windlass and or bollards in the bows and deploy a sea anchor or provide a means to tow the ship to safety. It was impractical for a number of reasons but mainly because ropes chaffed and when substituted with chain of sufficient strength. it was too heavy for the helicopter to lift it!

Under the ShipArrestor program, several alternatives to the chain problem were investigated and the only apparent solution appeared to be a chain made out of titanium. Manufacturing titanium chain is very difficult if not too difficult however a FSU space and defense metallurgical institute came up with an alternative steel chain that was lighter per ton and with a greater breaking strain than the originally proposed titanium chain. The next problem was how to keep the lasso open so the helicopter could drop it over the windlass. This was achieved by putting the chain inside an inflatable collar of about 6m diameter. Although this operation is not easy, helicopter pilots are adept to this sort of task as it resembles their work routine in the oil & gas industries.

Once the windlass is ringed, a 30m diameter sea anchor can be deployed to bring the bow round, reduce roll and slow the drifting until a tug can commence towing. The sea anchor diameter is critical; without the anchor the ship normally lies beam on and the hull itself acts like a sea anchor. If a too small sea anchor is deployed, it pulls the bow round and the decreased hull area with the small sea anchor is less than the hull beam on, so the drift rate actually increases.
In June 2010, the complete ShipArrestor system was tested just off the North Cape in arctic Norway. One helicopter, one tugboat and one LNG tanker participated. The tests were considered a major success in proving its functionality and practicability, however the calm weather conditions were too good to give any definite indication as to how the system would behave in a real life situation.
There were some minor problems in handling the system and some flaws in the test procedure which should be rectified prior to the next set of tests. The program is due to run to September 2010.

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