IMO Tier III: What It Means for Your Fishing Vessel

Since January 2016, the International Maritime Organization (IMO) has required all new vessels operating in designated Emission Control Areas (ECAs) — including the North Sea, Baltic Sea and Norwegian Exclusive Economic Zone — to comply with Tier III NOx emission limits. These limits are approximately 75–80% stricter than the previous Tier II standards.

For fishing vessel owners and operators, this means one thing clearly: any new build or vessel undergoing a major conversion must be equipped with an approved NOx reduction system. And with Norway's NOx Fund actively incentivising retrofit installations, the economic case for upgrading existing vessels has never been stronger.

BLUNOX A/S has been delivering SCR systems specifically designed for the demanding conditions aboard commercial fishing vessels since 2003. Our Digital Airless Multipoint technology is the world's most compact and energy-efficient solution — engineered to fit where traditional SCR systems simply cannot.

Why Fishing Vessel Operators Choose BLUNOX

Fishing vessels present unique challenges for SCR installation: limited engine room space, highly variable engine loads during fishing operations, salt air corrosion, and the need for minimal maintenance at sea. BLUNOX SCR systems are engineered to meet all of these demands.

✓ No Compressed Air Required
Traditional SCR systems require a separate compressed air supply for urea injection — adding complexity, cost and a new failure point. BLUNOX Airless TwinJet Nozzles eliminate this requirement entirely, using our patented digital dosing technology to achieve precise urea injection without compressed air.

✓ Industry-Leading Compactness
The BLUNOX catalyst is ultra-compact and designed to fit within the existing silencer space of your engine. No exhaust gas mixers, no long urea injection pipes, no flow dressers. On vessels where space is at a premium — from 42 m trawlers to 80 m purse seiners — this is the difference between a feasible installation and an impossible one.

✓ Proven for Highly Variable Engine Loads
Fishing operations demand constant acceleration, deceleration and load variation. The BLUNOX Digital Dosing System responds dynamically to engine load in real time, maintaining optimal NOx reduction across the full operating range — where competitors' systems struggle to maintain efficiency.

✓ Retrofit or New Build — Turnkey Delivery
Whether you are fitting out a new vessel at the yard or retrofitting an existing vessel during a scheduled drydock period, BLUNOX delivers a complete turnkey solution: concept design, detailed engineering, manufacturing, factory acceptance testing, installation support and commissioning.

Case: Fishing Vessel LEINEBJØRN

Owner: Leinebjørn AS · Engine: Caterpillar C280-12 (3,460 kW) · Installation: Retrofit

The LEINEBJØRN is a Norwegian fishing vessel operated by Leinebjørn AS. Following mandatory IMO Tier III requirements, the vessel was retrofitted with a single BLUNOX SCR system on its Caterpillar C280-12 engine rated at 3,460 kW. The installation was completed during a scheduled drydock period with no unplanned downtime. The vessel now complies fully with IMO Tier III NOx limits and is cleared for operation throughout all Norwegian and North Sea ECA zones.

Technical Specifications — BLUNOX SCR for Fishing Vessels

BLUNOX SCR systems for fishing vessels are engineered to cover a broad range of engine types, sizes and exhaust configurations. The table below summarises the key technical parameters for typical fishing vessel installations:

How BLUNOX SCR Technology Works

Selective Catalytic Reduction (SCR) is the most proven and effective technology for removing NOx from diesel engine exhaust. The BLUNOX SCR system represents the next generation of this technology, built around our patented Digital Airless Multipoint process:

1. Airless injection of urea solution directly into the exhaust stream using BLUNOX TwinJet Nozzles — no compressed air, no injection pipe running the length of the exhaust.
2. Conversion of urea to ammonia (NH3) within the exhaust gas, uniformly distributed across the full cross-section of the exhaust flow.
3. Reduction of toxic NOx to harmless nitrogen (N2) and water vapour through the SCR catalyst — the same nitrogen that makes up 79% of the air we breathe.
4. Clean exhaust output with NOx reduced by up to 97%, fully compliant with IMO Tier III limits.

Unlike traditional SCR systems, BLUNOX requires no compressed air supply, no long urea injection pipes, no exhaust gas mixers, and no flow dressers. Fewer components means less maintenance, higher reliability, and a smaller installation footprint — critical on working fishing vessels.

Frequently Asked Questions

Q: Does my fishing vessel need to comply with IMO Tier III?

If your vessel was built or underwent a major conversion after 1 January 2016 and operates in a designated Emission Control Area (ECA) — including the North Sea, Baltic Sea, or Norwegian ECA — then yes, IMO Tier III compliance is mandatory. Contact us to confirm whether your specific vessel is affected.

Q: Can a BLUNOX SCR system be retrofitted to my existing vessel?

Yes. The majority of our fishing vessel installations are retrofits. The BLUNOX system's ultra-compact design means it can be installed on most fishing vessel engine configurations during a scheduled drydock period. We have successfully retrofitted vessels from 42 metres to 80 metres in length, on engines ranging from 1,520 kW to 6,000 kW.

Q: How long does a retrofit installation take?

For a single-engine fishing vessel installation, the typical on-vessel installation time is 5–10 days during drydock, depending on the specific engine room layout. The complete project timeline from initial contact to commissioning is typically 3–8 months.

Q: Can I get funding for the installation through the Norwegian NOx Fund?

Yes, if your vessel operates under Norwegian flag or in Norwegian waters. Eligible projects can receive up to 75% of the total investment as a grant when installing BLUNOX SCR.

Q: Does the BLUNOX system require compressed air?

No. This is one of the key advantages of BLUNOX technology. Our Digital Airless Multipoint system uses patented TwinJet Nozzles that achieve precise urea injection without any compressed air supply — eliminating a major source of complexity and potential failure in traditional SCR systems.

Q: Which engine manufacturers does the BLUNOX system support?

BLUNOX SCR systems are compatible with all major marine diesel engine manufacturers, including Wärtsilä, Caterpillar, MAN, MaK, Bergen, Cummins and MTU. We design each installation specifically for the engine type and exhaust characteristics of your vessel.

Q: What maintenance does the system require?

The BLUNOX system is designed for minimal maintenance at sea. The primary consumable is urea solution (AdBlue). The catalyst itself requires periodic inspection (typically annually). The digital control system provides continuous performance monitoring and fault alerts.