Decarbonisation: Early Collision Avoidance Decisions Can Cut Emissions

Maritime decarbonisation is usually framed as a fuel and propulsion challenge. But there’s another lever available right now, on every voyage: operational stability.

When collision avoidance decisions happen late, ships tend to burn more fuel. Not because the route suddenly changes dramatically, but because last-minute actions often create inefficient manoeuvring:

• harder turns and overswings

• more speed changes (slow down and catch up)

• extra distance before rejoining the intended track

That’s a safety problem and an emissions problem.

Why “late” becomes carbon-expensive

Collision avoidance is not “free.” Abrupt manoeuvres increase drag and disrupt the vessel’s speed profile. And in real operations, crews don’t always slow down early when risk is rising, often due to commercial pressure, ETA anxiety, or habit. Gard’s loss-prevention guidance highlights this reality and warns that hard helm actions without timely speed reduction can lead to large overswings that are difficult to control.

The decarbonisation takeaway is simple: if you can make avoidance earlier and smoother, you reduce energy waste.

What SafeNav changes

SafeNav is a safety product first. A COLREG-aligned decision support system built to help navigators and ROCs take earlier, clearer, compliant action.

From an emissions perspective, that translates into fewer moments where a bridge team is forced into “reactive driving.” In practice, SafeNav aims to reduce:

• speed volatility during close-quarters situations

• unnecessary deviation from intended track

• high-energy manoeuvring caused by delayed decisions

This is not voyage routing. It’s making collision avoidance less disruptive to the vessel’s efficiency.

What we can realistically claim today

It’s tempting to quote big fuel-saving numbers from broad voyage optimisation studies. But those include multiple levers (routing, weather, trim, engine settings, port coordination). Collision avoidance is only one slice of the picture.

So our claim stays conservative:

In encounter-heavy operations, earlier and smoother collision-avoidance behaviour can support low single-digit fuel and CO₂ reductions - up to ~3% - depending on traffic density and operating profile.

That’s the right investor-grade framing: small, believable, and undoubtably meaningful at scale.

Turning fuel saved into CO₂ saved

For emissions accounting, the strongest part of this story is that it’s measurable.

Once fuel savings are quantified (via fuel flow, shaft power, or validated performance models), CO₂ savings follow directly using IMO conversion factors. For example, the IMO commonly used carbon factors are approximately:

• HFO: ~3.114 t CO₂ per tonne of fuel

• Diesel/Gas Oil: ~3.206 t CO₂ per tonne of fuel

That means a 1-3% fuel reduction is effectively a 1–3% CO₂ reduction, and it can be reported in tonnes with transparent assumptions.

How we’ll prove it

The best way to make decarbonisation claims “real” is to tie them to operational KPIs you can show, audit, and repeat.

SafeNav’s decarbonisation validation approach is straightforward:

1. Measure how early action happens

   • time-to-first-action / TCPA at first action

2. Measure how disruptive avoidance is

   • speed variability during encounter windows

   • track deviation miles before rejoining route

3. Translate operational improvements into fuel/CO₂

   • fuel delta → CO₂ delta using IMO factors

This allows owners, ROCs, and partners to see whether “earlier and smoother” is happening, and what it means in real fuel and CO₂.

The bottom line

SafeNav’s decarbonisation value is a co-benefit of safer navigation:

• earlier decisions

• smoother compliance

• fewer energy-wasting last-minute manoeuvres

• measurable low-single-digit fuel and CO₂ reduction potential in encounter-heavy operations

In a sector facing tightening climate targets and cost pressure, even low single digits matter, especially when they come from a tool that is primarily built to reduce collision risk.

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Sources we reference:

• IMO Third GHG Study (speed vs fuel sensitivity): https://greenvoyage2050.imo.org/resources/third-imo-ghg-study-2014/
• Gard (why speed isn’t reduced in time and overswing risk): https://gard.no/insights/what-stops-you-from-reducing-speed-to-avoid-a-collision/
• Skuld (high-traffic straits context): https://www.skuld.com/4a24b7/contentassets/d0459c5f5be24a1a938a9eece0ebcb15/collisions-in-the-malacca-and-singapore-straits.pdf
• IMO fuel→CO₂ conversion factors (CF): https://wwwcdn.imo.org/localresources/en/KnowledgeCentre/IndexofIMOResolutions/MEPCDocuments/MEPC.308%2873%29.pdf