Instruction manual

Understand the following procedures before drilling to ensure a clean hole through the

deck. Boats have a very hard gelcoat surface with fiberglass under the gelcoat as

shown below.

Gelcoat

The gelcoat is a very thin layer approximately 1/16

” thick and the fiberglass below it is

normally about 3/8” thick. IMPORTANT: If the fiberglass below the gelcoat is less than

3/8” thick, you need to add fiberglass cloth and/or marine treated plywood to build up

the largest available area to at least 3/8” thick. You need to check all mounting points as

the fiberglass thickness may vary on the boat.

You MUST run the drill in reverse while drilling the holes or the gelcoat will chip, as it is

extremely brittle. Remember to run the drill in reverse for the entire hole

This is also a great time to have someone with a vacuum to remove the fiberglass as

you are drilling. To drill the holes use the following procedures:

1) Begin with a 1/8” bit and run the drill in reverse until you are through the

fiberglass.

2) Repeat the same step as above with the 5/16” bit running in reverse.

3) Finish the hole by putting a slight angle (chamfer) on the edge of the gelcoat

turning the ½” drill bit by hand (without the drill) as shown on the right side in the

above diagram to further protect the boat.

4) Using the backing plate, double check the location of the second hole for each

base and then drill the second hole using steps 1-3.

5) Confirm the two Item 1 bolts will go through the backing plate and the two holes

without binding. If needed, drill the holes to 3/8” for clearance.

6) Optionally, you can use a small piece of sand paper to radius the edge of the

chamfer also to remove the slight edge..