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Propulsion Efficiency Report
Retrofit spending is shifting from one big fix to layered efficiency packages
Owners looking at existing tonnage in 2026 are rarely choosing between “do nothing” and one dramatic machinery project. More often they are assembling an improvement stack. That stack can include engine conversions, tuning and turbocharger work, energy-saving devices around the propeller, shaft generator upgrades, air lubrication, and digital services that identify where a ship is really leaking fuel. The strongest packages are the ones that match the vessel’s operating profile instead of copying a fashionable retrofit from another segment.
Engine-side route
Fuel flexibility
Dual-fuel conversions and targeted engine upgrades remain one of the most visible retrofit tracks.
Aft-ship route
Power reduction
Propeller inflow devices and propeller upgrades can still offer some of the cleanest efficiency math.
Digital route
Better decisions
Trim optimisation, hull analytics, and onboard advisory tools are now part of the propulsion story.
The retrofit market is getting more practical
Owners are moving away from generic upgrade talk and toward specific packages that solve measurable operating problems
In 2026 the retrofit market is being shaped by one simple reality. Most of the ships still expected to trade deep into the next decade already exist. That pushes attention toward packages that can be installed during drydock, tied to actual fuel-burn problems, and stacked with other upgrades. Some owners are using retrofits to unlock future fuels. Others are chasing lower fuel burn through propulsion devices, air lubrication, digital trim advice, or engine and turbocharger upgrades that better fit slower operating profiles.
Dual-fuel conversion
Engine efficiency upgrade
Propeller and aft ship
Digital performance
Lifecycle services
Air lubrication
What the best packages are solving
Fuel flexibility
Giving existing ships a path toward LNG, methanol, or other lower-carbon operating modes where feasible.
Giving existing ships a path toward LNG, methanol, or other lower-carbon operating modes where feasible.
Part-load efficiency
Improving machinery performance on ships that now spend more of life at slower and less efficient operating points.
Improving machinery performance on ships that now spend more of life at slower and less efficient operating points.
Propulsion losses
Reducing wasted energy at the stern through better inflow, less slipstream loss, or reduced hull friction.
Reducing wasted energy at the stern through better inflow, less slipstream loss, or reduced hull friction.
Operational leakage
Using advisory, analytics, and optimisation services to stop ships from burning more than the hardware needs.
Using advisory, analytics, and optimisation services to stop ships from burning more than the hardware needs.
8 retrofit packages and propulsion services worth watching
This table focuses on the packages and service categories owners are most likely to evaluate for existing ships rather than newbuild-only concepts.
| # | Package or service | Main value | Watch | Best fit profile | Main caution |
|---|---|---|---|---|---|
| 1️⃣ |
MAN PrimeServ dual-fuel conversion packages
Two-stroke and broader retrofit-upgrade pathway
|
Fuel flexibility plus longer competitive life | Owners keep watching this because it turns existing engines into future-fuel candidates rather than forcing every decarbonisation decision into a newbuild order. | Ships with meaningful remaining life, strong utilisation, and realistic access to alternative-fuel economics. | Conversion logic only works when fuel supply, vessel life, and full project scope all line up. |
| 2️⃣ |
WinGD X-DF retrofit upgrades including iCER and VCR paths
Focused on improving existing X-DF engine competitiveness
|
Better efficiency and lower emissions on an installed dual-fuel base | Worth watching because this is not a concept-only story. It reflects a growing effort to upgrade the first wave of dual-fuel ships rather than replacing them. | Operators with existing X-DF vessels seeking tighter efficiency and compliance performance from installed machinery. | The value depends on the installed base and on whether the ship’s commercial life justifies another technical cycle. |
| 3️⃣ |
Everllence PrimeServ four-stroke upgrade and digital Asset+ pathway
Fuel use, lubrication, reliability, and digital performance stack
|
Lower fuel use plus longer-life optimisation | This route matters because many owners are not chasing one dramatic conversion. They are looking for structured upgrade programs that cut fuel, improve control, and extend useful asset life. | Four-stroke fleets, genset-heavy vessels, ferries, cruise-related applications, and owners focused on lifecycle value. | Incremental programs can underwhelm if owners expect headline gains from small upgrades alone. |
| 4️⃣ |
Accelleron turbocharger and EPLO-style efficiency upgrades
Turbocharger and engine matching for today’s operating loads
|
Better performance in the power range the ship actually uses | Worth watching because part-load operation has become more common, and old engine settings do not always suit current trading patterns. | Ships spending more time at slower speeds or in operating profiles far from original design assumptions. | It is powerful as a targeted efficiency fix, but it is not a substitute for broader propulsion losses elsewhere on the vessel. |
| 5️⃣ |
Wärtsilä EnergoFlow and related propulsion efficiency upgrades
Pre-swirl stator and broader propulsion service route
|
Lower propulsion power demand through better inflow | Owners still watch this category closely because stern-flow devices can create clear fuel savings without the complexity of a full engine conversion. | Ships where propeller inflow improvement and aft-ship optimisation offer a cleaner payback path than engine-side capital. | Hydrodynamic fit matters. Not every hull gets the same value from the same device. |
| 6️⃣ |
Becker Mewis Duct retrofits
Established energy-saving device for aft-ship efficiency
|
Reduced propulsion power demand and easier drydock installation | Still one of the easiest propulsion-efficiency retrofits for owners to understand and model, especially on the right hull forms. | Full-form or slower ships where wake improvement and propeller inflow conditioning have strong relevance. | The wrong hull profile can dilute the headline value. The best cases are usually vessel-specific. |
| 7️⃣ |
Silverstream air lubrication retrofits
Hull-friction reduction through microbubble carpet
|
Meaningful fuel and emissions reduction without changing the main engine | Worth watching because it gives owners a retrofit path that attacks friction losses directly and can be added to existing ships relatively quickly. | Large vessels and fleets with enough fuel spend to justify a more advanced hull-efficiency investment. | The business case remains vessel-type sensitive and should be tested against real operating conditions, not marketing averages alone. |
| 8️⃣ |
ABB OCTOPUS, PM shaft generators, and digital propulsion advisory services
Decision support plus more efficient onboard power architecture
|
Better trim, better power use, and lower hidden energy waste | This package type is being watched because not every improvement needs to be visible in the engine room. Some of the fastest gains come from better trim decisions, smarter power use, and more efficient shaft-generation hardware. | Owners who want operational savings across the vessel, not only inside the engine itself. | Digital and electrical upgrades work best when crews and shore teams actually use the data to change behaviour. |
The strongest 2026 retrofit themes
The market is clustering around a few repeatable logic paths rather than one universal answer
Future-fuel route
Engine conversion packages are still the boldest bet
These remain the most strategic retrofit decisions because they can reshape the ship’s future commercial profile.
Dual-fuel conversion packages remain worth watching because they address a problem simple efficiency retrofits cannot solve. They can change the vessel’s fuel flexibility and therefore its longer-term competitiveness. But they are still selective projects, not universal answers.
Best use case
Long remaining vessel life
Works best when
The ship still has enough years left and enough commercial reason to justify deeper machinery capital.
The ship still has enough years left and enough commercial reason to justify deeper machinery capital.
Main mistake
Chasing conversion headlines on ships that do not have the runway or fuel logic to support them.
Chasing conversion headlines on ships that do not have the runway or fuel logic to support them.
Part-load route
Engine and turbo upgrades are getting more attention again
This is a practical answer for ships whose operating profile no longer matches original design assumptions.
Many ships now trade more slowly or with different load patterns than they were originally optimised for. That is why targeted turbocharger and engine-efficiency upgrades remain commercially interesting. They can produce disciplined savings without forcing a full fuel conversion story.
Best use case
Slow steaming fleets
Works best when
The owner has a clear picture of the power range the vessel now lives in most of the time.
The owner has a clear picture of the power range the vessel now lives in most of the time.
Main mistake
Assuming engine-side optimisation alone will solve hull, propeller, and operational losses too.
Assuming engine-side optimisation alone will solve hull, propeller, and operational losses too.
Aft-ship route
Propeller and stern devices are still among the cleanest retrofit stories
They often avoid the complexity of fuel conversion while still attacking a large energy-loss area.
Pre-swirl stators, ducts, and related propulsion upgrades remain attractive because they tackle wasted propulsion power directly. They can often be installed in drydock, linked clearly to propulsion efficiency, and paired with other upgrades without rewriting the whole fuel strategy.
Best use case
Hull-specific payback projects
Works best when
The owner has a vessel-specific hydrodynamic case instead of relying on generic fleet averages.
The owner has a vessel-specific hydrodynamic case instead of relying on generic fleet averages.
Main mistake
Choosing a stern device by reputation alone rather than by actual hull and wake conditions.
Choosing a stern device by reputation alone rather than by actual hull and wake conditions.
Friction route
Air lubrication is no longer a fringe talking point
For the right ships, this has become a serious retrofit category rather than a future concept.
Air lubrication is being watched closely because it attacks hull friction without changing fuel or the main engine. On ships with large annual fuel bills, that can make it an attractive complement to more conventional retrofit packages.
Best use case
Large fuel-intensive vessels
Works best when
The ship type and operating pattern support a meaningful friction-reduction gain over time.
The ship type and operating pattern support a meaningful friction-reduction gain over time.
Main mistake
Assuming all vessel types will see the same savings band.
Assuming all vessel types will see the same savings band.
Digital route
Propulsion efficiency services are becoming part of the package
The value increasingly comes from combining hardware with better operating decisions.
Dynamic trim, route-aware optimisation, hull analytics, and real performance dashboards are now much more than nice extras. They help owners identify whether the next dollar should go into engine hardware, the aft ship, the hull, or simply a better operating method.
Best use case
Data-active operators
Works best when
The fleet actually feeds operational data back into technical and commercial decisions.
The fleet actually feeds operational data back into technical and commercial decisions.
Main mistake
Buying a dashboard without changing behaviour, maintenance, or voyage practice.
Buying a dashboard without changing behaviour, maintenance, or voyage practice.
Electrical route
More efficient shaft generation is still underrated
It is not glamorous, but better onboard electrical efficiency can matter more than people expect.
Permanent-magnet shaft generators and related power-side upgrades remain worth watching because they improve onboard efficiency without requiring a headline propulsion redesign. They also fit neatly into broader vessel optimisation packages.
Best use case
Continuous power demand ships
Works best when
The owner wants a lower-loss power architecture that integrates cleanly into existing operations.
The owner wants a lower-loss power architecture that integrates cleanly into existing operations.
Main mistake
Ignoring the interaction between mechanical, electrical, and operational efficiency decisions.
Ignoring the interaction between mechanical, electrical, and operational efficiency decisions.
Lifecycle route
OEM service packages are getting more strategic
More owners want packages that identify upgrades and then keep them working.
A growing part of the market is not buying a single retrofit product. It is buying a relationship that combines condition monitoring, upgrade recommendations, performance follow-up, and lifecycle planning. That makes service packages increasingly central to retrofit strategy.
Best use case
Fleetwide optimisation programs
Works best when
The owner wants to prioritize upgrades ship by ship using hard performance evidence.
The owner wants to prioritize upgrades ship by ship using hard performance evidence.
Main mistake
Expecting a service contract alone to create savings without concrete technical follow-through.
Expecting a service contract alone to create savings without concrete technical follow-through.
Best 2026 view
The market is rewarding packages not isolated products
The best answers increasingly combine several small and medium improvements into one stronger whole.
The most interesting retrofit projects in 2026 are rarely built around a single device. Owners are stacking propulsion hardware, engine-side upgrades, and advisory services so each layer protects the value of the others.
Best use case
Ships with clear remaining commercial life
Works best when
The owner treats retrofit decisions as a system problem rather than a catalog problem.
The owner treats retrofit decisions as a system problem rather than a catalog problem.
Main mistake
Picking popular technologies without first identifying where the ship is truly losing efficiency.
Picking popular technologies without first identifying where the ship is truly losing efficiency.
Filters that separate a smart package from a fashionable one
The strongest retrofit choices usually begin with these questions
Remaining vessel life
Deep retrofit packages need enough commercial runway to earn back capex and disruption.
Deep retrofit packages need enough commercial runway to earn back capex and disruption.
Operating profile today
A ship running far below original design speed needs different upgrades than one still near design conditions.
A ship running far below original design speed needs different upgrades than one still near design conditions.
Main source of fuel leakage
Owners should decide whether the problem sits in engine operation, hull friction, propeller inflow, onboard power, or voyage practice.
Owners should decide whether the problem sits in engine operation, hull friction, propeller inflow, onboard power, or voyage practice.
Drydock timing
The best packages are often the ones that can be stacked efficiently into a planned docking window.
The best packages are often the ones that can be stacked efficiently into a planned docking window.
Data discipline
Without before-and-after measurement, a good package can look ordinary and a weak package can sound stronger than it really is.
Without before-and-after measurement, a good package can look ordinary and a weak package can sound stronger than it really is.
Alternative use of capital
Every retrofit competes against other ways of preserving earnings and asset relevance.
Every retrofit competes against other ways of preserving earnings and asset relevance.
Interactive owner tool
Retrofit Stack Value Checker
This tool helps readers test how attractive a retrofit package may look when hardware savings, operating profile, and expected vessel life are considered together.
Base vessel assumptions
Project assumptions
Estimated annual fuel-cost savings
$676,000
This reflects the expected savings rate, the fuel bill, and the operating-profile fit factor.
Indicative payback
3.3 yrs
A directional payback before financing, installation complexity, and off-hire detail.
Five-year gross value
$3.38M
Useful for judging whether a package feels too small, about right, or surprisingly valuable.
This looks like a credible mid-range retrofit case. The package is not transformative on its own, but it can still become commercially meaningful if the ship has enough life left and the operating profile truly suits the upgrade.
Reader note
The strongest retrofit packages are usually the ones that fit the vessel’s real operating pattern and leave enough time on the clock to compound the savings. Bigger technology is not always the better answer.
The strongest retrofit packages are usually the ones that fit the vessel’s real operating pattern and leave enough time on the clock to compound the savings. Bigger technology is not always the better answer.