How to Seal Boat Windows

Written by will charpentier
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How to Seal Boat Windows
(Hemera Technologies/ Images)

While a torrent of water rushing around a window frame on your boat clearly indicates the seal on the window has failed, it's more likely that a trickle will be your first warning. Boat window frames are fitted through the window opening, with flanges on both the inside and outside of the frame to keep water out. Making repairs may seem simple, but the cause of the leak may not be the window itself; it may be damage to the wall around the window frame. The only way to make a proper repair starts with removal of the window.

Skill level:

Things you need

  • Screwdriver
  • Marine silicone caulk

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  1. 1

    Remove the trim frame--the decorative part of the inside window frame--with a screwdriver.

  2. 2

    Instruct an assistant to hold the window frame in place from outside the boat. Use a screwdriver to remove the screws from the inside flange--the outside part of the frame that fits through the wall of the boat and is held in place by a removable flange. The removable inside flange is one side of the U-shaped channel that keeps the window frame in place.

  3. 3

    Slip the window out of the opening in the side of the boat. Inspect the wall opening for damage or rot that might break the seal on your boat windows and repair the damage or replace deteriorated woodwork before continuing.

  4. 4

    Use a putty knife to scrape the old caulk from the window frame's flanges, both inside and outside. Apply marine silicone caulk to the underside of the window frame's outside flange. Apply caulking to the removable inside flange. Set the window back into the opening, set the inside flange in place and reattach it to the outside part of the window frame.

  5. 5

    Reattach the inside window trim to the window. Wipe any excess caulk from the woodwork surrounding the window frame and trim.

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