Airmar Cored Fiberglass Hull—How to Prepare Hull for Thru-Hull Housing - Manual (Page 2)

3. From inside the hull using the interior hole saw, cut through
the inner skin and most of the core. The core material can be
very soft. Apply only light pressure to the hole saw after
cutting through the inner skin to avoid accidentally cutting
the outer skin.
4. Remove the plug of core material so the inner core of the
hull is fully exposed. Clean and/or sand the inner skin, core,
and the outer skin (gelcoat) around the hole.
Warning : Always completely seal the hull to prevent water
from seeping into the core.
5. If you are skilled with fiberglass, saturate a layer of
fiberglass cloth with a suitable resin and lay it inside the hole
to seal and strengthen the core. Add layers until the hole is
the correct diameter.
Alternatively, a hollow or solid cylinder of the correct
diameter can be coated with wax and taped in place. Fill the
gap between the cylinder and hull with casting epoxy. After
the epoxy has set, remove the cylinder (see Figures 2 and 3).
6. Clean and sand the area around the hole, inside and outside,
to ensure that the sealant will adhere properly to the hull. If
there is any petroleum residue inside the hull, remove it with
either mild household detergent or a weak solvent, such as
alcohol, before sanding.
7. Proceed with the bedding and installation instructions that
came with the sensor.
Checking for Leaks
Caution : Never install a thru-hull sensor and leave the boat in
the water unchecked for several days.
When the boat is placed in the water, immediately check around
the thru-hull sensor for leaks. Note that very small leaks may not
be readily observed. It is best not to leave the boat in the water for
more than 3 hours before checking it again. If there is a small
leak, there may be considerable bilge water accumulation after 24
hours (probably not enough to cause water damage). If a leak is
observed, repeat the bedding and installation procedures
immediately.
AIRMAR
TECHNOLOGY CORPORATION
69 Meadowbrook Drive, Milford, New Hampshire 03055–4618, USA
Phone (603) 673-9570 Fax (603) 673-4624