When you don’t have to solve for fouling

This is a fundamentally different design philosophy. You are not solving for fouling. You are solving for mechanical integrity and then whatever else you want.

Every antifouling on the market is trying to solve the same problem: keep things from growing on your hull. The approach for decades has been chemical - from copper cladding in the past up to modern biocides that target specific critters. It works. It also means your hull is a continuous source of leachates, and whatever else the formulator decided to put in there.

Foul release took a different approach - if I oversimplify it, make the surface too slippery for organisms to stick. Silicone-based systems from Hempel and International dominate that category. They work well on a section of the market but they are soft, damage-prone, can be tricky to apply and cannot tolerate aggressive cleaning. If something does attach and harden, you are in a difficult position.

Pretty much everything in life is a trade-off and in this case the reduction of emissions to air via fuel consumption control has tended to outweigh the emissions to sea.

Another path that I think is the most intellectually interesting one in the coatings space right now: biocide-free hard coatings designed for proactive grooming.

The premise

The idea is simple but hard to execute. Instead of focusing on keeping the fouling off through a mastery of chemistry, you apply a hard coating and you clean it regularly before fouling has a chance to establish. Light, frequent grooming through whatever means (watch out for this article) - removes slime and early-stage biofilm while it is still soft and weakly bonded. The coating is engineered to survive this repeated contact without degrading.

This is a fundamentally different design philosophy. You are not solving for fouling. You are solving for mechanical integrity and then whatever else you want. And once you reframe the problem that way, a set of optimization targets opens up that SPC/FRC chemistry cannot touch.

What you can actually optimize for

Smoothness. Some of these coatings - particularly the silane/siloxane nano systems - cure to surface roughness profiles under 5 microns. That is glass-smooth. Others, like the glass-flake vinyl ester systems, start considerably rougher out of the gate but reportedly improve with repeated cleaning as the grooming action polishes the surface. There are reports of SPCs self smoothing although I couldn’t find any published studies. Someone independent should run a controlled comparison of FRC and SPC vs hard coatings.

Surface architecture. This is the really exciting one. When the coating does not have to concern itself with certain fouling related properties, the surface itself becomes a design variable. You are no longer constrained by the chemistry of polishing - you can engineer the surface for hydrodynamics.

Think sharkskin. Biomimetic riblet structures that reduce turbulent drag have been studied for decades in aerospace, but conventional antifouling chemistry makes them impractical on a hull - the surface is constantly changing as the coating depletes or fouls. A hard, stable, groomable surface is a different starting point. It holds its geometry. It can be textured at the micro scale and maintained there. GIT's graphene platelet technology is already working in this direction - orienting nanoscale structures to create specific surface energy profiles and flow characteristics that go beyond just "smooth."

The implication is that these coatings are not just passive protection. They are the beginning of engineered hull surfaces - where the coating is designed to hydrodynamically interact with the water, not just survive in it. That is a fundamentally different ambition than anything a biocidal or self-polishing system can offer, because those systems are, by definition, consuming themselves.

Emissions to sea. Near zero or zero. These coatings are inert. No biocides or oils leaching, no microplastic shedding, no copper discharge. Independent lab verification exists for some of the products below. As IMO’s biofouling guidelines tighten and port states move toward stricter discharge regulations - California’s copper limits are already forcing the conversation in the US - this becomes a compliance advantage, not just an environmental talking point. The February 2026 copper re-evaluation bill is a worry for those using it.

VOC emissions to air. High-solids formulations in this category are pushing 95%+ volume solids, which means very low VOC at application. For yards in regions with strict air quality regulations - or for owners who care about Scope 3 reporting - this matters. It also means better coverage per gallon and less waste. And note that I selected volume solids as the metric and not VOC content. The HAPS nonsense in the US is extraordinarily misleading.

Cosmetics. This one sounds trivial until you talk to a cruise operator or a yacht manager. A glossy, hard, cleanable surface stays visually clean between groomings. No streaking, no patchwork erosion, no visible polishing pattern. The hull looks like it was just painted, consistently, for years. For vessels where appearance is part of the brand - and that includes a growing number of commercial operators - this has real value. I remember talking to a container ship owner in the US whose vessels were often idle off the coast of Long Beach. They valued hull appearance very much because their name was plastered all along the topsides in giant letters.

Who is making these

The biocide-free hard coating space is still small enough that you can map the serious commercial players on one hand. Here is what is on the market today, with verified characteristics:

Product	Manufacturer	Chemistry	DFT	Track Record	Grooming	Differentiator
XGIT-FORCE	GIT Coatings (Canada)	Graphene-reinforced amphiphilic hard foul release (DPET technology)	Single coat over primer (detailed spec not published in public TDS)	XGIT-FUEL predecessor on cruise vessels (Coral Expeditions), propellers on Stolt Tankers (25 vessels), Pacific Basin (40 vessels)	Only biocide-free coating with LR Enhanced Type Approval for grooming (XGIT-FUEL 2024, XGIT-FORCE 2026). Robotic grooming; 1–4 month intervals	Guaranteed 6% out-of-dock power gain vs. premium biocidal AF. Up to 10% fuel savings claimed. Ice/fender impact resistant
Ecospeed	Subsea Industries (Belgium)	Glass flake reinforced vinyl ester resin	2 x 500 µm (1,000 µm total). High initial surface roughness - not a smooth-out-of-dock system	20+ years in market. RRS Shackleton: coating intact after 12 years in Antarctic ice. Verified non-toxic (independent labs, NL & Canada). 10-year warranty	Proprietary cleaning tools. Manufacturer claims hull smoothness improves with each clean (starts rough, gets smoother - the inverse of most coatings). 10-year drydock interval achievable	Longest track record in category. Ice-rated variant. Life-of-vessel design intent. Extremely abrasion/cavitation resistant. Note: if you ever need to remove it and go in a different direction, blasting off a glass-flake vinyl ester matrix is a serious undertaking. This is a commitment
SEA-SPEED V 10 X	Seacoat SCT (USA)	Silane/siloxane nano coating	2 x 125 µm epoxy + 1 x 150 µm finish coat	4–12% fuel reduction claimed (manufacturer data). 10-year warranty. No independently verified case studies published to date	Withstands 1,000+ grooming operations without damage. Surface roughness < 5 µm	95% volume solids, very low VOC. Glass-smooth finish. No heavy metals. Single-coat finish application
F2 EcoHull	F2 Eco (EU)	Hybrid polymer with Zeronic™ inorganic resin additive	Multi-coat system (detailed TDS not publicly available)	Primarily yacht/workboat scale to date. 5+ year durability with top-coat refresh (no full rebuild required)	Superhydrophobic surface, ultra-smooth. Fouling removal by light cleaning	Zero PFAS/PTFE. Zero solvents. Compatible with FRP, carbon, aluminum, steel, wood. Emerging technology - watch for commercial vessel scaling

The grooming dependency

But let’s not forget, this will not work out so well without a grooming program. A biocide-free hard coating without regular cleaning will foul. You are trading chemical intervention for mechanical maintenance, and if you do not hold up your end, there will be trouble.

This is the single biggest reason the category has not grown faster. It requires operational discipline. It requires either a robotics partner, a reliable diving contractor, or in-house capability for regular hull maintenance. It requires scheduling, tracking, and accountability. For operators who struggle to keep up with basic planned maintenance, adding hull grooming to the rotation is a real ask.

But for operators who can commit to it - and particularly for operators who are already doing regular in-water inspections or cleaning - the numbers shift dramatically. You eliminate biocide complexity and environmental liability. You extend drydock intervals. You maintain out-of-dock smoothness through the entire service period. And you never have to worry about whether your antifouling is compatible with your cleaning method, because the coating was designed to be cleaned from day one.

Where this is going

The regulatory environment is moving in one direction. IMO’s 2023 Biofouling Guidelines and the 2025 in-water cleaning guidance are pushing the industry toward proactive hull management and away from “apply and forget” antifouling models. Port states are tightening discharge limits. Classification societies are beginning to certify grooming compatibility - Lloyd’s Register’s Enhanced Antifouling Type Approval, currently held only by GIT Coatings among biocide-free products, is the first formal recognition that a coating and grooming regime can be validated as a system. It will not be the last. Jotun has already secured a similar approval for their SeaQuantum Skate paired with the HullSkater robot, albeit for a biocidal system - the classification framework is being built in real time.

The biocide-free hard coating market is small - probably in the range of $50 million today, or roughly half a percent of the ~$8 billion global hull coatings market. The broader biocide-free /low biocide category, including foul release and self-polishing systems, is approaching $500 million and projected to more than double by 2035. As robotic grooming technology matures and becomes more accessible, the operational barrier drops. As regulations tighten, the compliance advantage grows. And as more vessels build track records with these systems, the performance data will either validate or challenge the claims being made today.

The elephants in the room are the technical complexity of hard coating + robotics combined with cost. But to achieve near zero efficiency loss, its likely worth looking into.

I do not think biocide-free hard coatings are the right answer for every vessel. They require a level of operational commitment that not every fleet is set up for. But for the operators who are willing to think differently about hull performance - who see the hull as a maintained system rather than a painted surface - this category deserves serious evaluation.

The coatings that do not emit anything (or very little) might be the ones that perform the best. You just have to be willing to take care of them.

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I’m tracking the full hull performance ecosystem - coatings, robotics, cleaning systems, and everything in between. Follow along if you want the independent analysis.