How to Prep a Steel Hull to Paint

A steel-hulled boat is a durable and long-lasting investment, provided that the owner is precise in attending to normal routine-maintenance cycles. One essential task is repainting the hull. Over time, marine paint can crack or be scratched by barnacles, marine life and dock fenders, giving water a means of working its corrosive magic. With some effort and equipment, however, you can keep your hull well-painted and rust free.

Things You'll Need

  • Scraper and rags
  • Canvas bag (large enough to cover the propeller and housing)
  • Pressure washer
  • Sand blaster with 12 to 60 mls grit
  • Wire brush
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Instructions

    • 1

      Remove the hull from the water and allow it to dry. This is typically done by putting the boat in drydock or lifting the hull with a crane onto jackstands.

    • 2

      Using the scraper and rags, wipe down the hull and remove any attached foreign objects such as barnacles or algae rings. Secure any open seacocks or other ports through the hull and wrap the prop and its housing in a heavy canvas bag.

    • 3

      Pressure-wash the hull with clean fresh water. The pressure should be 2,000 psi or higher.

    • 4

      Sandblast the hull, using a fine grit of 12 to 60 mls. Ensure that all paint is removed, including from seams and pits.

    • 5

      Wash the bare hull with fresh water. This will remove any grit and salt crystals that may be hidden in fine cracks. Any foreign matter on the surface may cause the paint to blister.

    • 6

      Allow the hull to dry, then perform a detailed visual inspection to check for structural integrity and rust. Ensure that the seacocks and ports have a tight seal or solid weld. Remove surface rust with a fine wire brush, cleaning the spot when finished. Refer extensive rusting to a local shipyard inspector for a thorough safety check.