Hull, gelcoat & antifouling

How often should you antifoul a boat?

Updated: 4 min readCaranva Boats

Quick answer

In warm waters like the Mediterranean, antifouling is usually renewed once a year. It can last longer if the boat is used little or kept ashore, and less in marinas with heavy marine growth or for boats that cover many miles on ablative antifouling.

The general rule

In the Mediterranean, with warm water and strong light, most owners haul out and paint once a year, usually in late winter or spring so the hull is clean for the season.

What makes it last longer or shorter

  • Water temperature and nutrients: warm, enclosed marinas foul faster.
  • Boat use: ablative antifouling needs movement to work; an idle boat fouls more.
  • Antifouling type: hard antifouling withstands abrasion and haul-outs; ablative wears with use.
  • Number of coats and film thickness.

Signs you need antifouling

  • Weed or slime at the waterline despite cleaning.
  • Barnacles or growth on hull, propeller or trim tabs.
  • Loss of speed or higher fuel consumption.
  • Areas where primer or gelcoat shows through.

Between haul-outs, diver hull cleaning keeps performance up. More in how to clean a boat hull.

Make the most of the haul-out

Check anodes, propeller, shafts and through-hulls, and plan other jobs with the maintenance calendar. Looking for a pro? See our antifouling and haul-out service or compare yards and painters.

Frequently asked questions

What happens if I don’t antifoul?

The hull is covered in growth within weeks, the boat loses speed, burns more fuel and fouling can damage propellers, water intakes and sensors.

How many coats of antifouling are needed?

Usually two coats on the hull and a third on high-wear areas such as the waterline, bow and leading edges of keel and rudder.

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