How many labour hours does it take to strip bottom paint on a 30ft boat?

Stripping the bottom paint on a 30-foot boat like a Grady-White takes between 20 and 40 labour hours. Media blasting is the fastest route at 8 to 12 hours, while manual scraping and sanding push the job to the 30 to 45-hour mark.

Professional Media Blasting

For a modern 30-footer like a 2018 Grady-White, media blasting with dustless crushed glass or soda is the fastest method. A professional blast operator needs 4 to 6 hours of trigger time to strip a 30-foot hull back to the epoxy barrier coat or bare gelcoat. You must factor in another 4 to 6 hours for masking the waterline, tenting the boat with heavy-gauge polythene to contain the spoil, and the final clean-up. Expect to bill or pay for 8 to 12 hours of total labour.

The hourly rate for a blasting contractor is high, but the reduction in labour hours makes it cost-effective for a yard. Ensure the operator uses a low-pressure wet blast to avoid pitting the 2018 gelcoat. If the original barrier coat (such as International Interprotect) is sound, a skilled blaster can strip the antifoul while leaving the epoxy intact. This saves days of re-coating time.

Chemical Stripping and Scraping

If yard restrictions on dust and runoff prevent blasting, chemical stripping removes multiple layers of hard antifoul well. Applying a blanket stripper like Owatrol Dilunett or Peel Away Marine takes 3 to 4 hours. You then cover the hull with poultice paper or let the chemical dwell for up to 24 hours. Wear a respirator, goggles and nitrile gloves when handling marine paint strippers.

The heavy labour comes during the removal phase. Two workers will spend 12 to 16 hours dragging carbide scrapers (like the Bahco 650) down the hull to peel off the softened sludge. Add another 8 hours for the final wash-down, neutralising the hull, and a light orbital sand to key the surface for the new primer. Budget 25 to 35 labour hours in total. It is a filthy job, but it is quieter and less damaging to the gelcoat than aggressive sanding.

Dry Sanding the Hull

Tackling a 30-foot hull purely with sanders is punishing work and racks up the highest number of labour hours. You need an 8-inch rotary sander with 40-grit discs to break through the hard antifoul, followed by a 6-inch orbital sander (like a Festool ROTEX RO 150 or Mirka DEROS) with 80-grit paper to smooth the gelcoat. Hooking these tools to a HEPA dust extractor is mandatory for toxic antifoul dust.