Biofouling ROI Showdown: Foul-Release (Silicone) vs SPC Antifouling vs In-Water Hull Cleaning + Prop Polish

Simple Summary

Foul-release silicone creates a very slick skin so slime and light fouling do not grip well. The film performs best when the ship moves regularly because water shear helps keep it clean. Upfront cost and yard prep are higher than conventional paint, but owners often recover that through lower fuel burn and fewer aggressive cleanings when the vessel is active.

Fit check

• Wins with frequent sailing and steady speed profiles. The surface sheds slime better when water flow is regular.
• Helps fast turnarounds. Clean skin reduces shaft power for the same speed, which trims bunkers.
• Struggles with long idle periods. Stationary days can let slime film build that needs gentle cleaning.
• Requires careful surface prep. Smoothness and adhesion are critical for performance and life.

Yard scope checklist

Always follow the coating maker procedure and class or flag requirements.

Foul-Release ROI estimator

Enter your typical steaming hours, fuel price, and expected fuel saving from a clean silicone skin. Add yard costs and any off-hire.

Savings assume steady trading. Always verify with your noon reports and speed-power curve.

Care and use in service

• Keep the ship moving where possible. Regular movement helps the skin shed slime.
• Schedule soft cleanings at friendly ports. Use gentle pads that protect the film.
• Combine with propeller polishing. A smooth prop cuts power for the same speed.
• Log smoothness and fuel. Keep before and after data so ROI is clear.

Common pitfalls

• Rushing surface prep. Poor fairness or contamination can ruin performance.
• Using aggressive brushes. Hard tools can scar the film and create drag.
• Parking for long stretches. Idle weeks can need an extra soft clean.
• Skipping records. No photos or DFT logs makes warranty claims harder.

Simple Summary

SPC antifouling releases biocide and slowly renews its surface as the ship sails. It is the standard choice when you want solid protection with lower upfront cost than silicone. Performance depends on activity. Regular movement keeps the film polishing and the hull cleaner. Long idle time can build slime that needs careful, low-pressure grooming if local rules allow it.

Fit check

• Best for mixed routes and average speeds where the vessel is active most weeks.
• Lower yard bill than foul-release, with familiar application methods.
• Idle weeks in warm water increase slime. Plan gentle groom or an earlier check.
• In-water cleaning of SPC is often restricted or must use capture. Check port rules first.

Yard scope checklist

Follow coating maker procedures and class or flag requirements.

Care and use in service

• Keep the ship active so the film polishes evenly. Avoid long idle if possible.
• If slime appears, consider soft groom with approved pads and capture gear where allowed.
• Avoid aggressive brushing. It can strip biocide and shorten life.
• Pair with propeller polishing and a simple hull check schedule.

Simple guardrails

• Pick SPC grade for your speed profile. High-activity grades differ from slow-steaming grades.
• Log idle days by water temperature. Warm and still water increases risk faster.
• Confirm local rules before any in-water work on SPC. Many ports require capture or prohibit it.
• Use ISO 19030 style tracking for speed-power so savings are visible to the team.

SPC ROI estimator

Estimate savings from a fresh SPC system versus your current baseline. Enter fuel price, daily burn, activity, and costs. Add any gentle groom and prop polish you plan each year.

If in-water grooming is not permitted on SPC where you trade, set groom sessions to 0.

Compliance notes to check

• Local rules on in-water work for biocidal coatings and any capture requirement.
• Waste handling rules for captured debris and water from cleaning.
• Any port or state limits on specific biocide chemistries in new applications.
• Document your coating system, dates, and DFT for class and warranty records.

Simple Summary

Clean the hull and polish the prop to remove slime and roughness. This cuts drag and restores speed at the same power. Results are immediate. Cost is pay-as-you-go. The main limit is local policy. Many ports require capture systems and approved methods. Plan where you can do it and set a simple trigger so you clean before fuel waste spikes.

Fit check

• Best when you trade in warm waters and anchor often. Slime forms fast.
• Works for any coating. Use soft pads on foul-release to protect the film.
• Helps before long ballast legs. A clean prop gives a quick shaft power cut.
• Schedule at ports that allow cleaning with capture. Check rules in advance.

Method and tools

Match tool hardness to coating. Protect silicone foul-release with soft media.

Compliance checklist

• Port permission or notice. Some locations require prior approval.
• Capture requirement. Many authorities require debris capture.
• Waste transport and disposal receipts. Keep in your records.
• Contractor certification and insurance. Ask before booking.
• Coating maker limits. Written method statement for your system.

Cleaning + Prop Polish ROI estimator

Estimate annual savings from planned hull cleans and prop polishes. Use your own noon data. Penalty is the fuel loss you see before cleaning. Residual is the small loss just after cleaning.

Do not double count overlap days if you polish the prop on the same day as a hull clean.

Trigger rules and a simple log

• Clean when speed loss hits your trigger or at X days in warm water. Pick one rule and stick to it.
• Polish the prop at the same call if allowed. The prop is a quick win.
• Keep short records. Date, place, contractor, method, capture used, disposal receipt.

Keep copies of permits and receipts with the log.

Common pitfalls

• Cleaning at ports that do not allow it. Result can be fines or delays.
• Using hard brushes on silicone foul-release. The film can scar and lose benefit.
• No capture. Debris release can lead to penalties and bans.
• No baseline data. Without noon data you cannot prove savings or time the next clean.

General assumptions

Foul-Release (Silicone)

SPC Antifouling

In-Water Clean + Prop Polish

24-month net benefit — dollars

Podium — based on your inputs

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2. —
3. —

Cleaning + Prop Polish is service-based. Payback shown for coatings only.