The MIDAS touch

about swapping out the onboard kit if another solution appears more appropriate? After all, a defined output within a particular footprint appears supremely well-matched to a ‘plug-and-play’ approach.

DNV GL’s laboratory ship concept does just that. Envisioned as a vessel to test, qualify and benchmark new maritime technologies, Experior is designed to be flexible in terms of interchanging onboard components and systems. Therefore, it holds the potential for interrogating a vast array of alternatives, from superstructure and cabins to power and manoeuvring kit, to comms and control, mostly by sitting them in dedicated containers with monitored interfaces.

Although not a commercial vessel, the ideas behind Experior may hold a clue to the future: its set up allows clients to calibrate and optimise their own innovations against the lab ship’s digital twin before installation.

ANALYSIS

In fact, according to Knutsen, a digital twin may be part of a modular delivery, allowing systems to be pretested in the factory.

There’s a further advantage. “So far full vessel reliability modelling has been challenging,” he says. However, since each module will have a health check element, it’s possible to network these together, creating a “system of systems”. It would, he remarks, gradually build up over time, being far less costly and troublesome to implement than dropping an entirely new, ship-wide layer into place.

It may also help resolve another niggling issue: cybersecurity. There’s often persistent doubt that the vessel’s onboard systems are as watertight as the hull, so modularity should provide more reassurance - firstly, it could potentially reduce shared weak points, secondly it “ensures that software systems are always up to date and robust in the face of challenges”, says Sverre Torben of Kongsberg Maritime Digital.

COMPLEXITY

However, the MIDAS project has shown there are a few knotty issues to overcome - not all purely technical in nature.

Knutsen explains: “You can create a health indicator for a bearing with no problem, but doing the same for the power management involves thousands of signals. If the manufacturers are tasked with keeping their modules running, they will need to be able to pull the data out in the same way from any ship.” And, he adds, without it being “the labour-intensive process” it is at present.

It’s not just the OEMs: the information will have to be shared with owner, systems integrators and last but not least, the classification societies. As Knutsen underlines, “there are more than 10,000 ships on DNV GL’s books so we’ll need a good, sanitized way of sorting it all out”.

Although there is “some movement” toward developing an industry-wide ISO standard, he admits rather than trying to make existing arrangements line up, it’s far easier to accomplish coherency on a newbuild where a useable format can be implemented from the very start.

SAFETY

Any module worth its salt would need to cover all the bases: “Besides the monitoring, maintenance plans, approvals and so on, it would need to include designed-in safety systems,” points out Knutsen. The latter presents its own challenges as its characteristics change with the fuel. Take LPG, he says: “It’s heavier than air, so standard gas detection equipment in the ceiling won’t work.”

Further, while modularity relies on a set of discrete systems, safety kit appears to pull in the other direction.

Ammonia, for example is toxic and corrosive, so if there’s a failure in any part of the fuel supply, the entire ship could be endangered. Therefore, these safety systems have to extend throughout the whole vessel.

“There is no perfect fuel, no perfect way forward”, underlines Niclas Dahl of Alfa Laval. “They all have pros and cons: some may simply be limited in supply. Some, like ammonia, require more in handling the risks.” But he stresses, this should not stop development.

FUELS AND ENGINES

Wärtsilä has been playing with modularity for a while: Nico Höglund explains that development really picked up with the release of the Wärtsilä 31 medium-speed four-stroke: “Before that, if you wanted to change from diesel to dual fuel, you’d have to re-machine the engine block.... but the 31 makes it all much more straightforward, you basically only need to add the gas components.”

It sets the scene for what lies ahead. Höglund adds: “Both methanol and ammonia are currently being evaluated as potential next-generation fuels, partly because they have the potential of being created in a completely green supply chain.” Interestingly, both can also be kept in liquid form with a modest amount of pressure and cooling.

Therefore, Wärtsilä’s modular approach should enable easier conversions: “If you have a dual-fuel engine running on LNG, the installation already contains the majority of what’s required, such as the fuel storage tank,” says Höglund, although both methanol and ammonia will need modified fuel injection along with process equipment and corresponding safety systems.

MANAGEMENT

Despite sounding deceptively simple, these fuel changes “require very good engine management”, adds Höglund: ammonia ignites and burns differently compared to other methane fuels and likewise, methanol has a lower calorific value requiring a change to the automation software.

This is central, he says: “Outside its operational parameters, the engine can start to knock or miss-ignite. The engine’s automation system has to take action to ensure proper combustion in order to avoid a potential escalation of the situation, which could lead to shutdown. So it’s not just about optimising performance, it’s also about safety.”

Moreover Alex Grasman of MARIN points out: “One important factor is that burning alternative fuels in a

8 Modularity could

provide futureproof ship design and paves the way for greater standardisation

combustion engine makes for a narrow ‘operational envelope’ compared to diesel.” Further, heavy seas compound the issue by adding dynamic loads to the system.

In short, new fuels require “tests on timing and management, and a lot of time spent searching for the sweet spot”, says Höglund.

TWO STROKES

While it might be expected that four-stroke, diesel-electric vessels like Moxie are the first candidates for a modular approach, Knutsen points out the big container vessels also tend toward fairly typical drive lines “with one or two twostroke engines, propeller shafts and so on... so you could create a complete propulsion package delivered in a range of vessel sizes”.

Martinsen adds that when it comes to cargo ship engines “we are not suggesting swapping big lumps of metal, instead we’re talking about transitional technologies that can adapt to new requirements”.

In fact, large, robust two-strokes don’t need so much in the way of modification. For example high-pressure engines like those from MAN ES currently allow for mixing different energy sources such as methanol and ammonia with more standard LNG: “This strategy allows you to step down in stages over time, all the way to zero emission fuels.”

FUEL PATHWAYS

Ammonia and methanol aren’t the only candidates: there are potential crossovers from a number of directions. Wärtsilä has already equipped ethane carriers with 50DF engines, and within the company’s landside power generation arm are plants running on LPG. But there are varying levels of challenge inherent in repurposing the different engine systems and so fuel ‘pathways’ will likely open up.

For example, Höglund points out that as liquid petroleum gas, LPG, consists largely of propane and butane, “it needs rather different treatment to LNG - which is mostly methane”.

However, when it comes to big two-strokes, Dahl adds: “While ammonia is still in the development phase, LPG is a good first step.” The two have enough characteristics in common that MAN’s ME-LGIP engine can burn ammonia, using the same cylinder cover, injection valve and gas block - albeit with the addition of larger tanks.

Outside its operational parameters, the engine can start to knock or miss-ignite. The engine’s automation system has to take action to ensure proper combustion in order to avoid a potential escalation of the situation, which could lead to shutdown. So it’s not just about optimising performance, it’s also about safety ‘‘

FUTURE KIT

It’s worth mentioning alternative power technologies: “If you’re considering modularity, there’s a lot to be said for batteries,” says Höglund. And since the cells are now half the size and double the capacity of a decade ago, producers such as Stirling PBES are recoring their systems, retaining the cooling and control architecture but swapping the old cells for more efficient versions.

There are certain limitations: “If the amount of power taken out in one go stays at a similar level, your electrical equipment can remain roughly the same,” explains Höglund. However, increasing peak power output may impact other components, such as converters, transformers and switchboards - so those too could require future-proof capacity.

Likewise, ABB is now collaborating with Hydrogène de France on megawatt-scale fuel cell systems able to power ocean-going vessels. Further, since they’re going to be based on proton exchange membrane (PEM) solutions developed by Ballard, they only need pure hydrogen and oxygen feeds, allowing flexible positioning around the ship. In fact, PEM cell stacks are almost ideally suited to modular, distributed energy configurations.

RELIABILITY

For owners, yards and equipment manufacturers, modularisation promises greater reliability, lower lead and build times and generally far less fuss. Moreover, for class societies like DNV GL it could mean “a move toward system-level analysis, the focus shifting from individual ships to repeatable modules” says Knutsen.

What it doesn’t promise is lower CAPEX. In fact, some research suggests that it will initially be more expensive - how much isn’t currently known - though as Martinsen has already pointed out, placing the wrong bet on the future will likely cost more in the long run.

8 The Wärtsilä 31

medium-speed four-stroke has been designed for fuel adaptability

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DIGITAL VALVES STREAMLINE CYLINDER LUBRICATION SYSTEM

Hans Jensen Lubricators has launched a new lubrication solution that eliminates the need for cylinder lubrication pumps and offers a significant reduction in cylinder lubricant oil consumption rates

The new HJ Smartlube 4.0 solution represents the culmination of years of research into how to improve the efficiency of cylinder lubrication systems for two-stroke engines, while lowering operational costs.

Stefan Nielsen, chief commercial officer at Hans Jensen Lubricators discussed how the system had been designed with flexibility as a goal. “Our new product, HJ Smartlube 4.0 has the highest flexibility of any lubrication system available. Not only in terms of the advantages the technology brings in regards to main engine lubrication performance - but also how the system is based on a modular approach, where we started our design and succeeded with the ambition of making the most optimum cylinder lubrication technology for two-stroke engines, perfect for both newbuilding and retrofit projects.”

Current cylinder lubrication systems typically feature an oil station, a cylinder lubrication pump, and an injection valve. The new HJ Smartlube 4.0 operates without a lubricator through a single high-pressure cylinder lube oil line, removing the need for cylinder lubrication pumps. This is possible by making the injection valves electronic.

By supplying high pressure oil to all lube points simultaneously, the ability to inject lube oil has been moved up-stream into the cylinder lubricator injection valves. In effect, the valve now works as the lubricator itself, determining the timing as well as the duration of the opening.

The rationalisation of the installation has a number of economic advantages, as the time and components required for the system have been reduced, lowering CAPEX costs. In addition, the technology offers significant OPEX reductions, by potentially reducing CLOC and cylinder liner wear, which is expected to be reflected in time between overhauls (TBO).

The company itself believes that the new product represents a significant advance in cylinder lubrication. Nikolaj Kristensen, Hans Jensen Lubricators Head of R&D likened the potential impact of the new system to the introduction of common rail fuel injectors. “We believe that this system is the future of cylinder lubrication: it offers more advanced and flexible control, consistent oil injection, all achieved with an overall simpler system, while minimising cylinder oil consumption, and optimising the cylinder condition.”

SMART ALGORITHMS

The solution includes three different load-dependent feed rate regulation options to optimise cylinder liner conditions.

The direct control of the valves means that the system can provide more accurately timed injections, while very small amounts can be injected while maintaining spray quality.

The first of the algorithms, Multi Timing, uses the valves ability to inject oil more than once per revolution, and even divide the oil between different injections, all during the same engine revolution.

For example, the majority of the cylinder lubricant could be injected via SIP (swirl injection principle), in which the cylinder lube oil is vaporised in the high-pressure air and

distributed on a large area of the upper liner surface just before the piston passes, and 20% of the lubricant could be equally divided between the ring-pack compression and combustion strokes.

Another of the options, Automatic Cleaning Cycle, optimises cylinder lubrication feed rates over a 24-hour period to ensure that the feed rate reaches a high enough level for the cylinder lubricant to clean the cylinder.

8 The new HJ Smartlube 4.0

The increased flexibility offered by the HJ Smartlube 4.0 system is important because the lower sulphur oils being used since IMO 2020 took effect tend to have a lower lubricity, but intermittent higher feed rates can make use of lubricants’ detergency without sacrificing CLOC efficiencies.

A third algorithm, Delta timing, allows for optimum distribution and quantity at any given instance, providing

8 Nikolaj

Kristensen, Hans Jensen Lubricators Head of R&D