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DNV: New requirement for Selective Catalytic Reduction Systems enters into force on 1 May

New requirement is applicable for marine diesel engines installed on ships with keel laid on or after 1 November 2025 or with a delivery date on or after 1 May 2026.

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Classification society DNV on Tuesday (3 March) released a statutory news on a new requirement for Selective Catalytic Reduction (SCR) Systems, which will enter into force on 1 May 2026. 

The new requirement is applicable for marine diesel engines installed on ships with keel laid on or after 1 November 2025 or with a delivery date on or after 1 May 2026:

Recent changes to the SCR Guidelines have altered how NOx measurement accuracy is assessed for catalyst monitoring. The former ±5% accuracy requirement has been replaced by a more flexible but less clearly defined concept of “sufficient accuracy”. This update places greater responsibility on applicants to justify the performance and monitoring of the lifetime of NOx catalysts.

Key changes to the requirements for NOx measurements

The requirements for NOx measurement devices used to monitor catalyst condition and potential degradation have been amended. Under the previous guidance, such devices were required to achieve an accuracy of ±5% relative to a reference NOx analyser (chemiluminescence detector, or CLD) compliant with the NTC 2008 standard. This explicit accuracy requirement has now been removed.

Under the 2025 SCR Guidelines, the NOx measurement method must instead be “sufficiently accurate” to enable the reliable monitoring of catalyst condition and degradation. However, the guidelines do not provide a specific definition or quantitative criterion for what constitutes “sufficiently accurate”.

Implications

Consequently, it is the responsibility of the applicant to demonstrate that the deviation between the on-board NOx measurement device and an NTC 2008‑compliant reference analyser remains within an appropriate range to support a dependable assessment of catalyst condition and degradation. In doing so, consideration may be given to factors such as the inherent measurement accuracy of the device, its expected measurement drift over time, and the margin to the applicable NOx limit value.

In addition, the assessment may need to address not only the raw NOx measurement results (e.g. concentrations expressed in parts per million), but also the evaluation process used to interpret these results and to determine whether the catalyst remains in an acceptable condition.

It should also be noted that NOx measurement accuracy is influenced not only by the performance device itself, but also by the exhaust gas sampling location and the degree of exhaust gas mixing at the sampling point. These aspects should therefore be duly addressed during testing and verification.

A proposal outlining recommended actions to support the implementation of the requirements under the 2025 Guidelines on SCR systems is provided in the Appendix to this news.

Recommendations

To ensure compliance with the 2025 SCR Guideline, it may be necessary to update the documentation, including the Technical Files, for individual engines or for existing engine groups or families.

In addition, the requirements of the 2025 SCR Guideline should be considered when planning and conducting parent engine emission tests and when preparing the associated documentation for new engine groups or families.

References

IMO resolution MEPC 399(83), 2025 Guidelines on SCR

 

Photo credit: william william on Unsplash
Published: 23 April, 2026

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Methanol

Tsuneishi Solutions Tokyobay delivers first methanol fuel supply system for bulker

The LFSS is the first unit of T-SOL’s proprietary LFSS developed in-house and will be installed on a Kamsarmax bulk carrier, marking its first application on an actual vessel following a ClassNK AiP.

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Tsuneishi Solutions Tokyobay delivers first methanol fuel supply system for bulker

Tsuneishi Solutions Tokyobay (T-SOL) on Friday (24 July) said it delivered the first Low-flashpoint Fuel (MeOH) Supply System (LFSS) for medium- and low-speed diesel engines at the end of May 2026. 

The LFSS received Approval in Principle (AiP) from ClassNK in April 2024. It is the first unit of T-SOL’s proprietary LFSS developed in-house and will be installed on a Kamsarmax bulk carrier, marking its first application on an actual vessel following the AiP granted by ClassNK.

An LFSS is designed to safely and reliably supply alternative fuels with low flashpoints, such as methanol, to a vessel’s main engine.

The LFSS delivered by T-SOL has been developed specifically for medium- and low-speed diesel engines and features a simple and compact design in terms of its main components, dimensions and weight. The system is equipped with key components manufactured by Japanese suppliers, enabling the provision of instruction manuals in Japanese as well as prompt and flexible responses to customer enquiries.

As the LFSS is assembled in Japan, customers adopting T-SOL’s LFSS are not required to attend Factory Acceptance Tests (FAT) overseas or arrange for engineers from overseas equipment manufacturers to travel to Japan, thereby helping reduce both costs and operational burdens for customers. T-SOL also provides on-site technical support during commissioning and testing.

With the tightening and introduction of environmental regulations, marine fuels are entering a period of transition from heavy fuel oil to alternative fuels, including methanol. 

“The transition requires new expertise and considerable time for technical evaluation, increasing the burden on customers. Drawing on the expertise of its experienced engineers, T-SOL provides comprehensive support throughout each customer’s transition to alternative fuels,” the company said. 

Following the delivery of its first LFSS, T-SOL will continue to work to ensure a stable supply of LFSS units while advancing the research and development of technologies that contribute to greenhouse gas (GHG) emissions reduction, including engineering solutions for other alternative fuels. 

 

Photo credit: Tsuneishi Solutions Tokyobay
Published: 27 July, 2026

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Bunker Fuel Quality

VPS on lifeboat fuel quality: A safety of life at sea critical risk

Neil Chapman and Steve Bee said regular fuel testing, correct fuel selection, and proactive fuel management are essential to ensure lifeboats are ready when they’re needed most.

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Neil Chapman, Managing Director of Americas, and Steve Bee, Group Marketing and Strategic Projects Director of marine fuels testing company VPS, on Monday (13 July) said regular fuel testing, correct fuel selection, and proactive fuel management are essential to ensure lifeboats are ready when they’re needed most: 

Performance when its most critical

In an emergency, a lifeboat engine is not simply a mechanical asset, it is a life-saving system. If the fuel in that system is of poor quality due to degradation, contamination, or simply unsuitable for the operating environment, then the result may be failure to launch, manoeuvre, or sustain operation, when human lives depend on it. Fuel failures in lifeboats onboard Cruise Liners are high-consequence life-safety risk as the engine may be the only power source available during an emergency. It is a key SOLAS (Safety of Life at Sea) requirement that lifeboats should hold sufficient fuel to enable them to run at 6 knots for no less than 25 hours.

The primary consequence of a lifeboat failure is not the commercial  loss, but the potential failure of a safety-critical system during an abandon-ship scenario. Financial, legal and reputational consequences will undoubtedly follow but the immediate risk is to life.

Now with the inclusion of Biofuels and FAME in the marine fuel mix and assuming the same fuel used in the main engines may be used in the emergency systems, how do you verify the operability of the lifeboats in times of crisis?

Fuel grade DMX within the ISO8217 specification is specifically intended for use within emergency equipment. However, since this is not a mandatory requirement, marine gas oil (MGO grade DMA) used for other purposes on board, is often used to fill up lifeboat fuel tanks. This could lead to hazardous outcomes as the DMA grade fuel might not be suitable for its intended use. DMA fuel whilst acceptable for general machinery use, will unlikely provide the same assurance of low-temperature operability, ignition quality, storage reliability, or starting reliability required for emergency craft. The quality of the fuel in the lifeboat tanks may also deteriorate during storage. Hence it is essential to test and ensure that the quality of the fuel being taken into the tanks is ’fit for purpose’ and monitored at regular intervals. DMX fuel should be chosen due to its ability to operate at a lower temperature, superior ignition quality and  improved starting capabilities. However, this fuel only accounts for approximately 1-2% of the global supply, compared to the regular DMA grade.

Failure Modes in Emergency Operations

SOLAS compliance should not be viewed only in terms of carrying the required quality of fuel. The fuel must also remain fit-for-purpose regarding stability, cleanliness and be capable of supporting reliable engine operation throughout the vessel’s operation. Lifeboat failures are rarely a singular dramatic event, rather a chain of events. These are typically caused by degraded fuel, filter blockages or storage issues.  Incorrect handling and storage can result in the ingress of water, which with modern fuels, can promote the growth of filter blocking bacteria rendering the engine inoperable.  So rather than the issue being no fuel, it is more likely to be an issue of fuel that is of poor quality. As lifeboat engines may sit idle for long periods it potentially allows the fuel to degrade, if the correct due care and attention is not paid to this key piece of emergency equipment.

The handling and storage of fuel, coupled with the observance of quality operating procedures can lessen the risk of these failures, but are unlikely to eliminate them completely. However, the failure to follow established procedures can result in issues that are likely to cause catastrophic financial and reputational damage to the cruise line operator.

The most common failure modes in emergency lifeboats can be categorised as follows:

  • Fuel Starvation
  • Contamination
  • Degraded Fuel
  • Blocked Filter/Injectors

Contamination in the engine due to the presence of water, as previously mentioned, can be catastrophic as this can induce corrosion and oxidation, along with promoting microbial growth which results in filter blocking and fuel starvation to the engine.

If an engine fails to start, or runs poorly under load, due to fuel related issues this would likely cause a secondary emergency, compounding the reason the lifeboat was required in the first instance.

The danger with degraded fuel is that the risk is often hidden. A lifeboat may appear available, inspected and compliant, whilst he fuel inside its tank is steadily losing the properties required for reliable emergency operation.

IMO guidelines indicate that inspectors and regulators are increasingly looking at emergency systems for fuel compliance, highlighting its importance in the operation of a vessel.

Seasonal & Regional Fuel Requirements

Often overlooked are the cold flow properties of diesel and biofuels.  While hydrocarbon-based diesel has very good (low temperature) cold flow properties, this is not the case for biofuels, so lifeboats fuelled in the Caribbean for the summer season may be completely inoperable if the vessels are transferred to the Northeast or higher location, for a winter period.

Root Cause Failure Mechanisms

The failure to follow the appropriate standards which result in engine failure can be categorised as follows:

image 45

The Effect of Biofuels on Marine Fuel Quality

In a study recently completed by a major shipping line, blends of biofuels were tested for a wide range of parameters.  The findings were:

Biological growth appeared within the first month, increasing rapidly with exposure to light.

Within 3 months oxidative corrosion started to occur requiring regular monitoring.

46 CFR § 169.837 states:

“(2) The fuel tanks of motor propelled lifeboats have been emptied, and fuel changed once every twelve months.”

Yet the evidence shows fuel stability effectively starts to deteriorate within the first month and can be unusable by month 3.

Prevention Strategy

Fuel testing should be viewed as part of the vessel’s safety assurance programme. It provides evidence that the lifeboat fuel remains fit-for-purpose, not only on the day it was supplied, but throughout storage and across changing operational conditions. A strong housekeeping policy requires a multi-pronged approach to ensure operability in times of crisis; such steps include:

  • Housekeeping – ensuring the fuel system remains closed when not in use to eliminate the ingress of water.
  • Operation – frequently run the engines so that fuel and lubricants are cycled through the units.
  • Testing program – likely to be cheaper and more efficient than changing out the fuel. A well-developed fuel testing program can eliminate the need to change the fuel.
  • Documentation – by recording all the actions taken to protect the emergency systems historic data can be tracked.

Advanced Testing Programs

Due to the importance of these emergency assets several different tests should be considered to ensure the suitability of the fuel.  Testing should include:

  • Cold-Flow properties using Pour Point, Cold Filter plugging Point, Cloud Point
  • Water content for moisture
  • BYF for Microbial testing
  • Acid Number for corrosion tendencies
  • FAME for biofuels content
  • Sulphur for MARPOL Annex VI compliance
  • Visual Appearance
  • Viscosity for flow properties
  • Density
  • Flash Point for SOLAS compliance
  • Cetane Index

Conclusion

It is possible to avoid engine failures, but this can only be achieved with a well-documented and well-followed operating procedure.  Regular fuel sampling and testing along with general good housekeeping techniques will ensure these units are ready go when they are most needed. Once they are seen as an active safety-critical asset rather than a dormant emergency component the value in this process will be realized.

Lifeboat fuel quality is not a housekeeping detail, it is a Safety of Life at Sea issue. Emergency craft must be capable of starting manoeuvring and operating for the required duration whenever called upon. Sub-standard, degraded, contaminated, or unsuitable fuel can compromise that capability and turn an emergency response into a secondary emergency. Regular testing, correct fuel choice, controlled storage and documented fuel management provide the evidence and assurance that lifeboats remain ready when lives depend on them.

 

Photo credit: VPS
Published: 14 July, 2026

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Engine

VPS on precision testing for reliable engine performance: Importance of coolant analysis

Steve Bee of VPS highlighted that coolant analysis can prevent failures through early chemical detection, protect components, maintain performance, plus reduce costs and downtime.

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Steve Bee, Group Marketing and Strategic Projects Director of marine fuels testing company VPS, on Thursday (9 July) highlighted that coolant analysis can prevent failures through early chemical detection, protect components, maintain performance, plus reduce costs and downtime: 

Engine coolants play a critical role in protecting equipment performance, efficiency, and longevity. As cooling system technologies and coolant formulations continue to evolve, regular laboratory analysis has become an essential part of proactive maintenance.

It is widely known that coolants should be managed with the same discipline as other critical fluids, as chemical changes can develop long before visible failures occur.

However, it must be emphasized that coolant analysis is about reliability, not just fluid condition. Modern engines and cooling systems operate under higher thermal loads and tighter tolerances, so even small changes in coolant chemistry can affect corrosion control, heat transfer, and component life.

An effective coolant analysis service should provide operators with an early warning system, helping to identify contamination, degradation, and inhibitor depletion before they become operational failures. The service can be a practical tool for reducing downtime, preventing avoidable repairs, and extending equipment life.

As stated above, many cooling system issues start at the chemical level, long before anything is visible and without analysis you are effectively blind until a failure starts. Through coolant testing, risks such as corrosion, cavitation and scale formation can be detected long before damage occurs.

image 41

As an example, the above images show the damage that can occur when a coolant does not have sufficient concentration to provide adequate protection. This damage can appear as scale formation, reduced heat-transfer efficiency and lower flow rates, which can ultimately lead to corrosion.

Coolants don’t just control temperature, they also chemically protect engines and coolant systems. They effectively prevent corrosion of metals and components, reduce cavitation damage in liners and pumps and help avoid deposit build-up and blockages in heat exchangers. Its true that cooling system damage, is a major source of engine failure.

Coolants must be chemically stable in order to transfer heat effectively, as poor cooling performance directly impacts engine efficiency, fuel consumption and reliability. As a predictive maintenance tool coolant analysis moves operations from emergency repairs to planned maintenance.

Should coolants exhibit degrees of incompatibility, then further issues can arise. Mixing incompatible coolants can cause sludge formation, which will in turn affect coolant circulation, leading to reduced efficiency. In addition incompatible coolants can form sludge or gels, which negatively impacts circulation and heat transfer creating hotspots. Those hotspots can break down lubrication and cause micro-welding between piston and liner surfaces, leading to piston pick-up.

image 42

Historically, many coolants were relatively simple glycol/water formulations supported by inorganic inhibitors such as silicates, phosphates, or borates. However, modern coolants are more sophisticated, including OAT, HOAT, NOAT, POAT, and other specialized blends designed for longer service life and improved protection. This added sophistication creates a need for verification: when systems are topped up, mixed, contaminated, or serviced.

Organic Acid Technology (OAT) coolants, can be formulated with various organic acids such as Sebacate, which is an ester of sebacic acid. Sebacate exhibits low volatility and excellent flexibility at low temperatures. Also tolytriazole can be a component, which is best known as a thermally stable, metal corrosion inhibitor.

So organic acid technology uses organic acids to provide targeted corrosion protection, especially for aluminum and mixed-metal systems. The advantages are, long service life of up to seven years, reduced abrasive deposits, and protection that is generally gentler on seals and components. However, whilst such coolants offer long service life, OAT coolants are not maintenance-free. Its also possible that coolant protection can be slow to establish and performance can be compromised by incorrect mixing, contamination, or loss of inhibitor balance. This is where routine analysis helps verify that the coolant is still doing its job.

Hybrid Organic Acid Technology (HOAT) coolants are newer generation coolants which combine organic acid technology with selected inorganic additives. They aim to provide both long-life protection and faster initial corrosion control through improved heat transfer and cooling performance. This makes them attractive for demanding engines and systems where heat transfer, compatibility, and corrosion control are all critical. The important point is that HOAT chemistry is more complex than traditional coolant chemistry. That complexity can make correct identification, compatibility, and contamination control more difficult. The downsides to HOAT coolants are they are more expensive than traditional coolants, but more concerning is they can be more susceptible to becoming contaminated, affecting their effectiveness and lifespan. Therefore, routine lab testing helps confirm whether the coolant in service still matches the intended formulation and whether the inhibitor package remains effective.

The shipping fleet has numerous sectors and each have various considerations when it comes to the use of coolants:

image 43However, the underlying need for each shipping sector is similar, in that cooling-system reliability supports uptime, safety, and cost control. Deep-sea shipping, offshore and marine services, harbour and coastal operations, cruise and ferry operators, inland waterway vessels, plus port or terminal operators, all have equipment where coolant condition can affect reliability. The commercial message is that coolant analysis can be positioned alongside existing marine fluid management services, making it a logical extension rather than a separate standalone offering.

A typical coolant analysis test slate includes the following tests highlighting what each test parameter detects, their frequency and benefits:

image 43

To take an analogy from Oil Condition Monitoring, Coolant Analysis is effectively a “blood test” for the cooling system.

So in summary, Coolant Analysis can prevent failures through early chemical detection, protect components, maintain performance, plus reduce costs and downtime.

 

Photo credit: VPS
Published: 10 July, 2026

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