Yes you should learn from the past, but hopefully better safety measures will be incorporated on ammonia powered ships than on today’s (or earlier?) food processing plants.
That’s a totally fair point. Hearing about those leaks at processing plants really hammers home how nasty ammonia can be. I guess the only thing giving the industry confidence is that we already manage LNG/LPG safely, so the hope is they can get the containment/safety procedures right for ammonia, but it’s definitely the biggest hurdle that needs solving.
Looks like DNV have faith in the safety measures developed for use of ammonia as fuel on ships:
Once again I’ll make reference to the novel “The Mosquito Coast”. Allie Fox builds a freezer in the jungle which ends up polluting the area when it is unintentionally blown up.
Hopefully the technology involved on ships has got a step ahead of what happened in this novel from 1981. (Or did it actually happen?)
Quite a few studies has been made into the safety of Ammonia as fuel on ships:
Same for other potential fuels, incl. Hydrogen and Methanol:
In American parlance a novel is fiction.
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Who could have guessed.
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Ammonia is becoming one of the most likely type of future fuels for ships:
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As an instructor-assessor in the Maritime training center where I hold the decarbonisation course for engineers in action on board I have interest what price for 1 m3 of Ammonia? Green Ammonia, means production of this fuel must use renewable source of energy: solar or wing one. What a life cycle of this fuel?
From a chief engineer’s point of view, most future fuel decisions don’t fail because the fuel is wrong. They fail because the operational reality is underestimated.
On paper, everything looks manageable. In the engine room, new fuels usually mean more systems, tighter margins, more sensors, more procedures, and less tolerance for error. That complexity doesn’t show up in feasibility studies, but it shows up at sea.
Another issue is lock-in. Once tanks, piping, ventilation, and safety systems are built around one fuel, you’re stuck with it. The idea that conversion later will be easy often ignores space limits, downtime, and crew workload.
Training and support are also weak points. Certifying crews is one thing; maintaining real competence with high turnover is another. When something goes wrong, expert support isn’t always close or fast.
Decarbonisation is coming, no question. But the decisions that hold up best are the ones that keep systems operable, maintainable, and flexible — not the ones that assume everything will work exactly as planned.
That gap between slide decks and a night watch is where most fuel strategies fall apart.
From my point of view I’m glad I’m retired. Would I like to go to sea on a 15 year old vessel maintained to the standard we have come to expect with ammonia as fuel? Hell no.
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I’m glad I’m retired too!! 
That doesn’t mean that I think everything new is bad, or should be resisted.
I sailed on ships that didn’t have any of the modern machinery and equipment, but do not think that things should stay the same forever.
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The Chief Engineer’s Survival Guide to Alternative Fuels
Let’s be honest. From the engine control room, the global push for alternative fuels can feel less like a smooth transition and more like being told to swap out the ship’s main engine while at full sea speed. The webinars, regulations, and marketing brochures often miss the gritty, practical reality we live in.
My career, from Oiler to Chief on container ships, has been defined by keeping machinery running. Now, the industry is asking us to be pioneers again. This isn’t a tech manual—it’s a survival guide for the mindset shift, operational headaches, and new skills we’ll need to keep the lights on and the ship moving.
The New Fuel Landscape: A Chief’s Quick-Reference Chart
Before we dive into the trenches, here’s a clear, at-a-glance comparison of what’s coming at us. This is the “what we’re dealing with” summary.
| Fuel Type | The Chief’s Elevator Pitch | Key Operational Headache (The 3 AM Problem) | Crew & Training Impact |
|---|---|---|---|
| LNG (Liquefied Natural Gas) | The “Bridge” Fuel. Established tech, available now. A GHG reduction, not a full solution. | Boil-Off Gas (BOG) Management. Cryogenic temps (-162°C). Constant pressure management. A leak isn’t a spill; it’s a rapid phase-change cryogenic hazard. | High. Need certified engineers in cryogenics, gas handling, dual-fuel systems. Culture shift from liquid to gas mindset. |
| Methanol | The “Flexible” Contender. Liquid at ambient temps, simpler bunkering. Can be green or fossil-based. | Toxic & Flammable. Invisible flame, requires alcohol-resistant foam. Major material compatibility issues (seals, gaskets, piping). | Significant. Toxicity response training. Firefighting drills for invisible fires. New bunkering procedures. |
| Ammonia (NH₃) | The “Zero-Carbon” Promise. No carbon in the molecule, but… | Toxic, Corrosive, & New. Lethal toxicity at low concentrations. Unproven at marine scale. A leak could evacuate the port. | Extreme. Arguably the highest safety culture shift. Rigorous toxic gas response, medical training, and containment protocols. |
| Batteries / Hybrid | The “Puzzle Piece.” Perfect for short, fixed routes. Not for deep sea. | Thermal Runaway (Fire). An electrical fire with its own oxygen supply. Extinguishing requires new tactics and equipment. | Specialized. High-voltage electrical safety becomes paramount. Different diagnostic skills (software vs. mechanical). |
The Real Battlefield: Operations & The Human Factor
The chart tells you the “what.” The real fight is in the “how.” Our world is about to get more complex.
- Bunkering is Now a High-Stakes Science Project: Forget the old fuel samples. We’re talking about securing a Certificate of Analysis for every single batch. Is this methanol truly green? What’s the exact composition of this LNG? The margin for error on fuel quality is now zero, and the Chief is the final inspector.
- The End of the “Universal” Engineer: We grew up with diesel. The principles were largely transferable. Now, we face a fleet of “snowflake” ships—each with bespoke systems. A 2/E from an LNG carrier cannot walk onto an ammonia-ready ship without major, specific training. This fragments our skills and pools of qualified personnel.
- Safety Culture is Your New Most Critical System: With LNG, methanol, and especially ammonia, a procedural lapse isn’t just a breakdown; it’s a potential mass casualty event. The trust-but-verify culture we built around fuel oil needs to evolve into a validate-and-document-every-step culture. Drills will no longer be a checkbox; they will be the core of our operational readiness.
A Chief’s Action Plan: Surviving and Thriving
So, how do we not just survive but lead through this? From one engineer to another:
- Become a Student Again, Now. Don’t wait for company training. Use forums like this, study manufacturer docs for new systems (ME-LGIP engines for methanol, X-DF for LNG), and understand the underlying chemistry and physics. Your authority will come from being the most knowledgeable person onboard about the new fuel.
- Audit Your Own Safety Culture. Look at your engine room team. Are your Wiper and Oiler truly prepared to recognize the unique hazards of these new fuels? Start the conversations now. Build a culture of questioning and extreme procedural discipline.
- Demand Clear Procedures & Ownership. When your company introduces a new fuel, your first question should be: “Where are the clear, vessel-specific procedures for bunkering, gas-freeing, emergency isolation, and leak response?” If they don’t exist, making them is your first priority.
- Protect Your Crew’s Competence. Advocate fiercely for proper, hands-on training for your team, not just online modules. A technician who has physically handled a cryogenic LNG connection in training is worth ten who have only seen a video.
- Embrace the “System of Systems” View. These fuels tie the cargo system (for carriers), fuel system, propulsion plant, and safety systems into one interdependent web. You must now think like a plant manager, not just an engine room supervisor.
Conclusion: The Engineer’s Creed Remains
The fuels are changing, but our fundamental creed is not: We are responsible for the plant. We ensure the safety of the people working in it. We deliver the power required for the voyage.
The transition to alternative fuels is the greatest engineering challenge our profession has faced since the move from coal to oil. It will be messy, expensive, and fraught with unforeseen problems. But it is also a moment for the engineering department to step forward and lead with technical rigor and an unwavering commitment to safety.
They can design the ships and write the regulations. But we, the engineers, will be the ones to make it work. Let’s get to it.
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The ships under construction in China for dual fuel diesel and ammonia must be a step up in their quality control of pipe work than any I have seen before.
Even changing fuels from heavy oil to marine gas oil can have its hiccups and as usual with shipping usually takes place at 03:00 or there about. (No it’s not a dream Chief).
Followed by alongside at 7, change a unit during the day, sail at midnight .
Now let’s try that with ammonia.
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I’m not sure that is the likely scenario, or the meaning of “dual fuel”.
The way I understand it “dual fuel” means that the engine can run on HFO or MGO until such time as Ammonia becomes available in large enough quantities and at enough main ports to where it becomes operationally and economically feasible to change the vessel to operating on Ammonia only.
PS: I’m not well enough informed to know if it will be necessary to change to some other type of fuel for manoeuvring?
Anybody here with more understanding on the subject?
What “dual fuel” really means?
Dual-fuel does NOT mean “temporary fuel until ammonia arrives.”
An engine designed to permanently operate on TWO fuels, selectable at any time, for safety, redundancy, and operability.
Dual-fuel ammonia engines are designed to ALWAYS retain a conventional fuel
- There is no operational or regulatory concept of “ammonia-only” main engines at sea
- Even future ships will never fully abandon oil-based pilot or backup fuels
Why ammonia engines can never be truly “single fuel”
1 Ammonia does NOT ignite easily
Ammonia has:
-
Very high auto-ignition temperature
-
Low flame speed
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Narrow flammability range
Because of this:
-
A pilot fuel is required
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Typically MGO (not HFO)
So even when “running on ammonia,” the engine is actually: Ammonia + pilot fuel
2. Manoeuvring & low-load operation
This is where your instinct in the PS is absolutely correct.
During:
-
Manoeuvring
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Dead slow
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Crash stop
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Port operations
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Cold start
Ammonia is operationally problematic
Therefore:
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Engines will switch to MGO mode
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Or use high pilot fuel ratios
So yes — another fuel is almost certainly required for manoeuvring, especially in early generations.
3.Safety, redundancy & class rules
Classification societies will not approve:
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Loss of propulsion due to fuel unavailability
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A vessel that depends on a single toxic fuel supply chain
Dual fuel provides:
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Redundancy
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Compliance with safe return to port philosophy
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Emergency operation capability
What “dual fuel” ammonia vessels are REALLY designed for
| Scenario | Fuel Used |
|---|---|
| Open sea, steady load | Ammonia + pilot fuel |
| Manoeuvring | MGO |
| Cold start | MGO |
| Ammonia system fault | MGO |
| Ammonia unavailable in port | MGO |
| Emergency / crew safety | MGO |
So MGO is not a temporary bridge fuel — it is a permanent operational necessity.
Why companies still like the term “dual fuel”
Because it allows them to:
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Meet IMO decarbonization targets
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Retain operational flexibility
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Avoid commercial risk if ammonia is unavailable
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Satisfy charterers and insurers
It’s a risk-managed transition, not a hard switch.
Bottom line (engineer’s summary)
-
“Dual fuel” does NOT mean temporary
-
Ammonia engines will always need another fuel
-
Manoeuvring on ammonia alone is unlikely and unsafe
-
MGO will remain onboard for:
-
Ignition
-
Low load
-
Emergencies
-
-
Fully ammonia-only ships are not realistic with current physics, safety rules, or class requirements
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Thanks for your expertise!!
Many companies make dual fuel that are mgo pilot injection for lpg for many decades.
Its a requirement in many European rivers.
Now as above post mentions its all sorts of fuels.