Boat Bottom Paint Calculator

Basic vinyl paints are thinner and simpler formulations, so they spread further per gallon and cost less, but generally provide shorter-lasting antifouling protection. Ablative (self-polishing) antifouling paint gradually wears away in a controlled way to keep releasing fresh biocide, which requires a denser formulation that covers less area per gallon at a higher price. Hard or epoxy antifouling coatings are the densest and priciest, but resist burnishing and repeated scrubbing better, which matters for boats that get cleaned frequently or run at higher speeds.

Haulout and relaunch is a separate service the boatyard charges to physically lift the boat out of the water and set it back in, using a travel lift or similar equipment -- it happens regardless of who actually applies the paint while the boat is out of the water. Professional application labor is a distinct cost on top of that, charged only when the boatyard's crew does the painting itself, which is why choosing DIY application removes the labor line item but not the haulout line item.

It uses a simplified approximation common for displacement-hull boats: boat length multiplied by the sum of beam and draft, times a 0.85 correction factor that accounts for the hull's curved, tapered shape rather than treating it as a flat rectangle. This is a reasonable planning-level estimate for many recreational boats, but actual wetted surface area depends on the specific hull form -- a planing hull, a catamaran, or a boat with unusual underwater appendages (bulb keels, trim tabs, pod drives) can differ meaningfully from this general approximation.

A single coat is prone to thin spots and pinholes from minor application variation or hull surface texture, which can leave small areas without adequate biocide protection where fouling can start. A second coat fills gaps the first missed and builds the coating to a more reliable, uniform thickness, which is why most antifouling paint manufacturers recommend a minimum of two coats for maintenance painting, and three or more when painting down to bare hull.

They're general industry approximations by paint category, not a quote from a specific manufacturer. Actual coverage rate (square feet per gallon) and price vary by brand, formulation, and region, and are printed on the specific product's technical data sheet (TDS) -- always check the TDS for your chosen paint before finalizing a purchase quantity, since buying based on a generic estimate risks running short mid-project or overbuying.