Boat antifouling: haul-out, hull cleaning and bottom paint
Quick answer
Antifouling is the paint applied below the waterline to stop algae, barnacles and other organisms sticking to the hull. In the Mediterranean it is usually renewed once a year during haul-out, when the bottom is also cleaned and anodes, propeller and through-hulls are checked.
What antifouling is and why it matters
A fouled hull can noticeably increase fuel consumption and reduce speed. Antifouling is a paint containing biocides (or, in newer products, copper-free alternatives) that prevents marine growth below the waterline.
What a haul-out with antifouling includes
- Lifting the boat with a travel-lift or crane and blocking it ashore.
- Pressure washing the bottom and scraping off growth.
- Sanding and, where needed, priming bare gelcoat or metal.
- One or two coats of antifouling.
- Replacing sacrificial anodes, checking propeller, shaft, stern gland and through-hulls.
- Relaunch respecting the manufacturer's drying times.
Types of antifouling
| Type | How it works | Best for |
|---|---|---|
| Self-polishing (ablative) | Wears away with movement, releasing biocide steadily | Boats used regularly |
| Hard matrix | Hard film that resists abrasion | Fast boats or frequent haul-outs |
| Copper-free / eco | Alternative biocides or foul-release surfaces | Aluminium hulls and protected areas |
| Prop and drive | Formulas for metal surfaces | Drives, propellers and trim tabs |
Find out how often to renew it in how often to antifoul a boat.
Make the most of the haul-out
The annual haul-out is the best time for other jobs: engine service, gelcoat repairs or polishing and waxing the topsides. Plan it with our boat maintenance calendar.
Frequently asked questions
How often should a boat be antifouled?
In warm waters like the Mediterranean, usually once a year. If the boat is used little or spends long periods ashore, a hard antifouling may last a bit longer.
How much does antifouling cost?
It depends on length, marina and whether lift, pressure wash and anodes are included. The most reliable approach is to request all-inclusive quotes from several professionals.
Can I apply antifouling over a different type?
Only if they are compatible. Switching between ablative and hard antifouling may require a primer or removing the old coating. A professional will check before painting.
Antifouling & haul-out by port
Antifouling & haul-out: professionals by area
Related guides
How often should you antifoul a boat?
In the Mediterranean, once a year is the norm. Here’s what changes that and how to tell if your hull needs it.
How to clean a boat hull: topsides and bottom
Products, technique and frequency for cleaning the hull, removing bow yellowing and keeping the bottom clean between haul-outs.
Boat maintenance calendar: what to do each season
A simple annual plan to keep your boat ready: what to check before, during and after the season.
Other maintenance services
Gelcoat repair
Gelcoat is the pigmented resin layer that protects a boat’s fibreglass. Chips, deep scratches and cracks should be repaired promptly so water cannot reach the laminate. A professional repair opens up the damage, fills it with gelcoat or epoxy filler, sands through the grits and polishes until colour and gloss match.
View serviceBoat cleaning
Professional boat cleaning covers washing deck and hull with marine products, gentle teak cleaning without a pressure washer, rinsing stainless steel and cleaning interiors. The bottom can be cleaned in the water by a diver between haul-outs to keep performance up.
View serviceEngine service
Basic boat engine maintenance means changing oil and filters every 100–200 hours or once a year, replacing the raw-water pump impeller every 1–2 years, checking anodes, belts and coolant, and inspecting the fuel system. Doing it before the season prevents most breakdowns at sea.
View service