Some tips for fitting a rod holder to your boat; The following info here will not be exhaustive but we hope people will find it useful. Make sure you use all appropriate safety gear when doing these jobs. Step 1 is to drill the appropriate hole. Make sure you use the right size hole saw, this can be checked against the rod holder. Allow a little bit oversize for reasons I will explain later. Before you drill the hole check there is nothing underneath that will interfere with the rod holder and be damaged by drilling the hole. I recommend marking out with a pencil where the hole is going. A small pilot hole isn't a bad idea either.
In the case of fitting this type of rod holder it required the hole to be oval. This meant starting the hole saw then carefully tipping it as it cut. Further shaping can be done with sanding bobbins. Once the main hole is shaped place the rod holder in the hole and mark the screw holes. Select appropriate size and length screw and then select a drill size to match the shank. When drilling in fiberglass it is a good idea to use a drill that is a fraction bigger or wiggle the drill in the hole to stop the screw binding and breaking off the head. This happens easily with 316 stainless screws. Another tip so you don't rip up your gelcoat when you put in the screw is to take the driver tip and create a little countersink.
If there is timber under the fiberglass it is better to seal it with resin. This is why allow a little bit oversize with the hole saw
I like to dry run the screws in to make sure everything is ok before adding sealant. Some people prefer using a hand screw driver for this.
After giving the surfaces a wipe clean with Metho or similar add the sealant and screw up
Finally screw the rod holder down and clean up any excess sealant with Metho. For a really professional finish align all the screw heads.
This is some of the dust from the holes drilled again, make sure you use a dust mask and all appropriate safety equipment and clean up after finishing. We like to remove all upholstery when doing these kinds of jobs.