Modern leisure and commercial vessels alike are constantly chasing greater efficiency, but even light fouling on propellers and running gear can dramatically increase drag, fuel consumption, and power demand. Clean underwater metals don’t just improve performance — they can significantly reduce operating costs by helping vessels move through the water more smoothly and efficiently. In this article, we examine how foul-release coatings like PropOne help vessels maintain cleaner running gear, reduce fuel burn, and improve overall performance between dockings.
Does PropOne save you fuel?
Having clean running gear and propellers, provides substantial energy savings by reducing drag and restoring mechanical efficiency.
Fouling Release Coating Systems (such as PropOne): These specialized coatings are designed to make it difficult for organisms to adhere and are easier to clean.
Impact of Fouling on Energy Consumption
- Increased Demand: Even light to moderate fouling on a propeller can account for up to 50 percent of the increased energy demand on the ship
- Critical Fouling Levels: The presence of even immature barnacles or tubeworms on running gear causes a severe loss in efficiency.
- Surface Roughness: Biofouling increases the skin friction and wall shear stress. Even mild fouling moves the maximum efficiency point to lower rotational speeds, meaning a fouled system can no longer operate at the design specifications of a smooth, clean system.
- Increased Drag and Weight: Macrofouling (e.g., barnacles, mussels) increases both the weight of the submerged components and the hydrodynamic drag, leading to severe performance impairment.
There are several performance indicators of energy loss, ship performance changes that indicate excessive fouling and associated energy waste:
- Fuel Consumption: An increase of more than 5 percent in the fuel required to maintain a specified shaft RPM.
- Shaft RPM: An increase in shaft RPM of more than 5 percent to maintain a given speed.
- Torque: For ships with torsion-meters, an increase in torque at a given shaft RPM.
High-precision testing on a commercial vessel showed that applying a foul-release coating to a clean propeller resulted in a 7.5% reduction in fuel consumption.
Power Efficiency: There was a recorded 4.7% decrease in kilowatt (power) usage at cruising speed.
The Comparison: Crucially, this test compared a clean, uncoated propeller against a clean, coated propeller. This proves that the coating provides a hydrodynamic advantage beyond just preventing growth—it makes the metal surface smoother than the bare metal itself, reducing skin friction.
VEEM EXTREME: High tensile stainless steel propeller
Grade |
||||
Element |
AISI 316 |
AISI 431 |
Duplex AISI 2205 |
Super duplex AISI 2507 |
| Iron | 61−72% | 76−84% | 65−70% | 58−65% |
| Chromium | 16−19% | 15−18% | 21−23% | 24−26% |
| Nickel | 10−14% | 1−3% | 5−7% | 6−8% |
| Molybdenum | 2−3% | ≤1% | 3−4% | 3−5% |
| Manganese | ≤2% | ≤2% | ≤2% | ≤2% |
| All Others | ≤1% | ≤1% | ≤1% | ≤2% |
"Stainless steel allows the design of propellers with smaller thicknesses and consequent reductions in weight, inertia, and fuel consumption."
What can be done
Specifically targeting propulsors, shafts, struts, and rudders is highly effective; approximately 50% of total fuel savings from a full hull cleaning are attributed to cleaning these specific components.
Mechanical Cleaning Strategies: One method for restoring performance is the mechanical removal of biological growth while the ship or turbine remains in the water.
Underwater Cleaning: Removing fouling from the hull and propulsors between scheduled drydockings restores ship systems’ performance and economy.
Protective Coating Systems: Using coatings helps prevent or delay the onset of fouling:
- Antifouling: These systems deter growth through the release of biocides.
- Fouling Release Coating Systems: These specialized coatings are designed to make it difficult for organisms to adhere and are easier to clean
In a recent independent study using high-precision data monitoring on a commercial vessel, the effectiveness of foul-release coatings was quantified.
The study found that even when comparing a clean uncoated propeller to a clean coated one, fuel consumption was reduced by 8% and kilowatt usage dropped by 5%. This confirms that a coating like PropOne doesn’t just prevent fouling; it optimizes the hydrodynamic efficiency of the vessel’s running gear from the moment it hits the water. For boat owners, this translates to an immediate return on investment and a significant reduction in seasonal fuel costs.
Stainless steel EWOL propeller coated in PropOne
Benefits of Foul Release Coatings Like PropOne
The relationship between clean running gear and fuel efficiency is well documented across both commercial shipping and recreational vessels.
Increased roughness from slime, tubeworms, and barnacles dramatically increases drag and reduces propulsive efficiency. Studies have shown:
- Even light fouling can increase propulsion energy demand by up to 50%
- Fuel consumption increases greater than 5% are considered a strong indicator of excessive fouling
- Propeller fouling shifts the vessel away from its optimal operating efficiency point
In a monitored commercial vessel trial using high-precision performance analysis, a foul-release coating applied to a clean propeller demonstrated:
- Approximately 7.5–8% reduction in fuel consumption
- Approximately 4.7–5% reduction in kilowatt power demand at cruising speed
Crucially, these results compared a clean uncoated propeller versus a clean coated propeller.
This is significant because it confirms the coating itself provides a performance advantage by reducing surface friction and improving smoothness beyond bare metal alone.
Additional industry studies on silicone foul-release technologies have reported drag reductions ranging from 2% to 23% compared with conventional antifouling coatings due to their smoother surface profile.
For commercial operators, these gains translate directly into:
- Lower fuel spend
- Reduced engine loading
- Lower CO₂ emissions
- Improved speed retention between dockings
Because fuel burn and carbon emissions are directly linked, even a modest 5–8% fuel reduction can represent a substantial emissions reduction across a fleet over a full operating cycle.
Operational monitoring consistently shows that maintaining clean running gear produces measurable benefits in:
- Fuel efficiency
- Speed retention
- Reduced shaft loading
- Lower power demand
For high-utilisation merchant vessels, even relatively small efficiency gains can create significant annual savings due to rising fuel costs and tightening emissions requirements.
The importance of propeller and running-gear efficiency is now so well recognised that many operators consider these surfaces among the highest-return areas for vessel performance optimisation.
Fuel Reductions: Fossil-fueled ships can realize fuel savings of more than 15 percent by having clean propellers.
Performance Restoration: Cleaning results in significant speed increases or a reduction in the power required to maintain a specific speed.
The “Self-Cleaning” Mechanism: Organisms like barnacles and slime struggle to stick to the slick PropOne surface. Once the vessel is placed in drive and reaches a certain speed (typically 10–12 knots, though even lower for fast-moving propellers), the sheer force of the water dislodges the fouling.
Reports show that silicone foul-release coatings can exhibit 2% to 23% less drag than standard tin-free self-polishing coatings because they have a smoother surface profile, whereas traditional paints have a rougher texture.
Fouling is primarily a threat during static periods. PropOne addresses this by ensuring that while a vessel left sitting may still see lingering growth, it is not permanently bonded. A simple light underwater wipe or the motion of the propeller itself is often enough to restore a clean surface.
Final thoughts
Keeping propellers and running gear clean is one of the most effective ways to improve vessel performance, reduce fuel consumption, and lower operating costs. By creating a slick foul-release surface that helps prevent marine growth from bonding permanently, PropOne helps both recreational and commercial vessels maintain efficiency for longer between dockings. As fuel prices continue to rise, solutions that reduce drag and restore performance are becoming increasingly valuable for vessel owners worldwide.
