Re-bedding a hatch

Catalina 30, hatch, re-bed, sealant, Sika Flex -

Re-bedding a hatch

We were seeing dripping from the hatch above the head on our Catalina 30, so we took a closer look at the hatch above decks. We could see a void in the caulking around the hatch, so decided it was time to re-bed the hatch. Having never done this before, I called upon the expertise of Jim Knapp, of Kula Marine in Gig Harbor. 

Here is the list of tools you will need:

  • screwdriver (hatches are usually screwed on with phillips head screws, but double check what you have)
  • small hammer (ball peen hammer works well)
  • large flat head screwdriver or flat chisel
  • plastic stir stick
  • caulking gun

Here is a list of products you will need:

  • Sealant ( Jim recommends SikaFlex, which we carry at Ship to Shore)
  • Acetone
  • Paint thinner or denatured alcohol
  • gloves (disposal work well to prevent messy hands and prevent chemical skin irritation) 
  • clean shop rags
  • paper towels


  1. Open the hatch and unscrew all of the screws, and place screws in container so they don't get lost.
  2. Once all screws are removed, use hammer and flat head screwdriver or flat chisel to pry up hatch carefully.
  3. Remove hatch, then flip it over and remove/scrape off all caulking/silicone. If silicone was used before, it is critical to remove ALL of it by scraping down thoroughly.
  4. Then clean deck surface around the perimeter of the hatch cut out thoroughly, dry, then wipe down both deck and the underside of the hatch with acetone.
  5. Using the SikaFlex loaded into a caulking gun, apply a generous bead of caulk carefully around the underside of the hatch.
  6. Next flip hatch over and screw in but not all the way, squeezing some off caulk out.
  7. When screws are all in, cinch down all screws, starting with ones that are on 'less flat' part of deck if the deck has a camber (or curve).
  8. Its going to look messy at first. when its squeezed out it means there is no gap. if there are gaps, add a bit more caulking (if on a camber deck this can happen)
  9. Use a plastic stir stick to pull off excess sealant around edges, and scrape off onto rag or paper towel.
  10. Put paint thinner or denatured alcohol on a clean shop rag and wipe around edges to clean up around sealant still left on deck.
  11. Let dry.

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