A new report from Lloyd’s Register (LR), titled Energy Saving Devices Retrofit Report: Applying Advanced Propeller Designs to Ships, indicates that demand for advanced propeller retrofits and energy-saving devices (ESDs) has increased nearly four-fold since 2020.
This surge is driven by shipping owners and operators seeking to improve energy efficiency to comply with stricter emissions regulations.
The report notes that high-efficiency propellers can achieve fuel savings of 3-10%, while devices like rudder bulbs can deliver 3.5% reductions.
However, only 1.74% of the global fleet is currently equipped with rudder bulbs, the most common ESD, from newbuilds.
The orderbook reflects greater adoption, with 8.42% of vessels on order featuring ESDs, a rate two to six times higher than for the existing fleet.
Bulk carriers, tankers, and container ships are identified as prime candidates for retrofitting due to their high fuel consumption.
For instance, 16.87% of bulk carriers on order will include rudder bulbs, compared to 6.74% of the existing fleet. In the container ship segment, at least 10% of vessels (both existing and on order) feature rudder bulbs, stator fins, or boss cap fins.
Over 10,000 vessels in the global fleet and orderbook have some form of propulsion energy-saving technology from newbuild, with an additional 1,400 vessels retrofitted with ESDs since 2020.
By the end of 2024, nearly 1,500 vessels are expected to have contracted ESD retrofits.
The report highlights a shift toward retrofitting newer vessels, with over one-third of 2024 retrofits performed on ships less than ten years old, compared to 16% in 2020.
In 2024, 12% of retrofits were on vessels built within the past six years, a category absent from retrofits in 2020.
Regulatory pressure is the primary driver, with the International Maritime Organization’s (IMO) Carbon Intensity Indicator (CII), Greenhouse Gas (GHG) strategy, and European regulations like the EU Emissions Trading System and FuelEU Maritime linking vessel performance to financial penalties.
LR’s analysis suggests that a 20% reduction in fuel consumption could save an Aframax tanker operator nearly US$3 million over ten years through reduced regulatory costs in Europe.
Challenges in retrofit implementation include technology selection, potential device interactions, unverified performance claims, and vessel-specific requirements.
Some technologies fail during full-scale validation despite promising model test results.
Biofouling on propeller blades and ESDs can also reduce efficiency by increasing surface roughness and altering hydrodynamic profiles.
LR recommends a five-step approach to address these issues: comprehensive vessel assessment, hydrodynamic analysis using computational fluid dynamics, consideration of technical factors like torsional vibration and underwater radiated noise, performance monitoring, and long-term maintenance planning.
Claudene Sharp-Patel, Global Technical Director at Lloyd’s Register, stated: “Our research reveals that propeller and ESD retrofits offer ship operators a proven pathway to significant fuel savings, extended regulatory compliance, and meaningful emissions reductions. However, successful propeller and ESD retrofits require far more than simply bolting on additional equipment. They demand sophisticated analysis, careful integration with existing systems, and ongoing performance management. Our role extends throughout the entire retrofit journey, from initial assessment through long-term optimisation.”
The report is part of LR’s Retrofit Research Programme, which, alongside the Fuel for Thought series, provides insights into adapting vessels for cleaner shipping.
Lloyd’s Register is a global professional services organization specializing in marine classification, ship design, energy transition advisory, compliance, and consultancy services for the maritime industry. Established over 260 years ago, LR supports shipowners and operators in meeting regulatory requirements and improving operational efficiency through services like retrofit solutions, emissions management, and digital tools.