A routine antifouling job on a 35 ft sailboat lands near $3,600 all-in at a US yard — and the paint itself is the smallest line on that invoice. A full topside repaint in two-part polyurethane is a different order of money: $300–800 per foot. This page itemises both bills, explains which bottom paint fits your cruising, and shows when a gelcoat correction is the smarter first move than a repaint.
What a bottom job actually costs, line by line
Yards quote antifouling per linear foot, but two quotes at the same rate can describe completely different work. One assumes a sound, already-prepared surface; the other includes travel-lift time, blocking, blasting and disposal. Always ask for the itemised version. A typical US quote for a 35 ft sailboat getting a standard ablative repaint looks like this:
| Line item (35 ft sailboat) | Typical cost |
|---|---|
| Haul out and relaunch | about $1,200 |
| Pressure wash | about $175 |
| Yard storage, 5 days | about $350 |
| Bottom prep and sanding | about $350 |
| Paint application labour | about $875 |
| Paint, 2.5 gal ablative | about $625 |
| Environmental / disposal fee | about $50 |
| Total | about $3,600 |
As a rule of thumb from published yard schedules: light prep plus two coats runs $8–12 per foot for prep and $25–40 per foot for application; stripping years of buildup adds $25–40 per foot; an epoxy barrier coat adds $15–25 per foot. Paint quantity is predictable — underwater area is roughly length × beam × 0.75, and a 45 ft sailboat needs about 3–3.5 gallons for two coats. If a quote skips the environmental fee or assumes no sanding, expect those costs to reappear later as extras.
Which antifouling type fits the way you actually use the boat
The choice is decided by use pattern and water temperature, not by price per gallon. Ablative paints wear away with use and water flow, exposing fresh biocide, and suit boats that move. Hard modified epoxies suit faster boats and hulls that get scrubbed regularly, but they build up layer on layer until the hull eventually needs stripping. Copper-epoxy systems sit outside both categories.
| Type | Repaint interval (saltwater) | Best for | Main caveat |
|---|---|---|---|
| Ablative / self-polishing | 1–2 years | Cruising sailboats that move regularly | Aggressive scrubbing shortens its life |
| Multi-season ablative | 2–3 years | Boats used weekly through the season | Costs more per gallon |
| Hard modified epoxy | 1–2 years, builds up | Fast powerboats, racing, mud berths | Layers accumulate; eventual strip-down |
| Copper-epoxy (Coppercoat type) | 10–15 years | Full-time cruisers avoiding haul-outs | Strip to gelcoat; reactivation sanding |
| Copper-free / silicone foul-release | varies | Aluminium hulls, restricted waterways | Higher cost, weaker on hard growth |
In freshwater the same paints stretch: 2–4 years between jobs is normal because fouling pressure is far lower. In water that stays above about 24 °C year-round, treat all intervals as annual.
The application numbers that decide whether the paint lasts
Most antifouling failures trace to application conditions, not the product. Manufacturer data sheets converge on the same limits:
- Strip or sand back to a sound, clean, dewaxed surface; pressure wash first and let the hull dry fully.
- Apply only when the hull and air are at or above the stated minimum — most products specify 5 °C / 50 °F — with relative humidity below 85% and the surface at least 3 °C above the dew point.
- Roll two coats at the specified dry film thickness — about 40 microns per coat on typical products — plus a third coat at the waterline, rudder edges and any area that takes abrasion.
- Respect the immersion window: most paints want at least 24 hours between the final coat and launching, and hard epoxies may need scuffing and recoating if the boat sits ashore past their maximum window.
- Match the paint to the hull metal. Copper biocide attacks aluminium, so an aluminium hull or aluminium saildrives and trim tabs need copper-free paint and an insulating primer.
One more number worth knowing: a hull left uncoated and fouled can burn up to 40% more fuel than a clean one. The paint bill is cheap insurance against the drag bill.
Copper-epoxy systems: the ten-year arithmetic
Copper-epoxy coatings embed almost pure copper powder in a waterproof epoxy matrix. The manufacturer quotes 10–15 years of service, and long-term user reports broadly support a decade or more in temperate water, somewhat less in the Caribbean. The money case is straightforward: materials for a 40 ft hull run about €1,400 across four coats, against €300–400 for a single season of conventional antifouling — so skipping two or three haul-out cycles pays for the difference. When the surface darkens and growth starts to hold, a light sanding with 400-grit reactivates the copper.
The catches are real. Every previous antifouling layer must come off, down to gelcoat, before application — hulls have lost fresh coatings after a single season when prep was rushed on glossy gelcoat. The coating also needs correct thickness and cure conditions, which is why many owners pay an applicator. And regulation is patchy: the Netherlands no longer permits new applications, and Sweden and Norway restrict it in some marine reserves, so check local rules before committing.
Topsides: a 10-to-15-year decision, not a seasonal one
Above the waterline the question is usually restore or repaint. A full two-part polyurethane repaint (Awlgrip, Alexseal and equivalents) typically runs $300–800 per linear foot for an Awlgrip-grade finish and puts the boat in the yard for 3–6 weeks. Done properly, the finish holds a like-new look for roughly 8–15 years. Three things decide whether you get the good outcome:
- Prep dominates. Fairing, priming and sanding are most of the hours and most of the bill; the topcoat is the last day. A suspiciously cheap quote usually means less fairing, and you will see every low spot in flat afternoon light.
- Never mix systems. An Alexseal topcoat belongs over Alexseal primer, Awlgrip over Awlgrip. Cross-system jobs are where warranties end early.
- Think about repairs. Alexseal's topcoat can be cut and polished to blend a scrape; classic Awlgrip was not designed to be buffed. A boat that lives against a busy dock rewards the repairable system.
If the gelcoat underneath is structurally sound, restoration is the cheaper move: light machine polishing runs about $35–60 per foot, multi-stage wet-sand correction $50–100+ per foot, and a ceramic or graphene coating $60–70 per foot on top. A corrected gelcoat holds its look 1–2 years — up to about 3 with a coating — so restoration buys seasons, not years. The same restore-versus-replace arithmetic applies to teak decks. Repaint when the gelcoat is too thin to sand safely, when crazing runs deep, or when blisters or moisture readings point below the surface. A pre-purchase survey that includes moisture meter readings is worth commissioning first; our survey guide covers what to order.
Copper rules are tightening — check before you buy the paint
Antifouling biocides are under active restriction, and the map is uneven. California caps the leach rate of copper antifouling sold for recreational vessels at 9.5 micrograms per square centimetre per day, and in-shore basins such as San Diego's Shelter Island Yacht Basin restrict in-water hull cleaning of copper paints. Washington State wrote a law that would restrict antifouling above 0.5% copper from 2026, but its ecology department's 2024 review found no safer alternative that is equally effective, so the restriction has not taken effect — a follow-up review is due by 2029. In northern Europe, Denmark has expanded the list of antifoulings banned for private boats under 24 m, and the EU's biocidal products regulation gates what manufacturers can sell at all.
Practical response: ask your yard which products are currently registered where you keep the boat, confirm the rules for in-water cleaning at your marina, and budget for proper disposal of sanding dust and old paint — the environmental fee on the invoice above is not optional anywhere. Once the paint is on, the metals below the waterline need their own routine; our corrosion prevention guide covers shafts, struts and anodes. For the rest of the seasonal round that keeps a hull out of trouble, see our maintenance checklist.
Frequently asked questions
How often should antifouling be reapplied? In saltwater, plan on every 1–2 years for an ablative and every 2–3 years for a multi-season product. Warm, high-growth water pushes that to annual. Freshwater boats often stretch to 2–4 years.
Can I paint the bottom myself? Usually, if the yard allows owner work. Count 8–16 hours for a 30–35 ft hull, wear a respirator and disposable suit, and expect to save $500–1,500 in labour. Hire the yard when the hull needs stripping, blister repair or a barrier coat.
Is a copper-epoxy system worth it? For a boat kept in the water year-round, often yes: roughly €1,400 in materials for a 40-footer against a decade of seasons and haul-outs. Budget for stripping to gelcoat, apply it carefully, and confirm it is permitted where you cruise.
What does a professional topside repaint cost? About $300–800 per linear foot for an Awlgrip-grade finish and 3–6 weeks of yard time. If the gelcoat is sound, start with correction and polishing at a fraction of that and repaint when the surface is genuinely exhausted.
Start every paint season with an itemised quote and a moisture check, not a colour chart. The paint is the cheapest line in the yard's invoice; the prep, the haul-out and the surface condition underneath decide what you actually pay.