Besides docking on a windy day with a new boat in front of an audience, drilling holes is one of the most dreaded tasks for a do-it-yourself boater. But boats are full of holes, from antennas on the hardtop to transducers on the bottom. So why do we fear them?
Probably because, on some level, we know water isn’t our element. Despite our boat blessing us with the ability to visit a different realm, a special place reserved for the members of our rank, its primary purpose is to keep the water out.
There’s merit to this fear. According to marine survey firms, leaks at through-hulls are estimated to be the cause in 18 percent of sinkings while under way. The numbers are worse at the dock, where failures of fittings below the waterline account for a full 50 percent of sinkings. BoatU.S. insurance claims back up the data. According to BoatU.S. numbers, fittings cause 44 percent of dockside sinkings and 16 percent while under way.
But, if you want conveniences like a head or livewell, or even an extra cleat, you’ve got to drill holes. To learn more, we went to the pros at Regal Boats and documented the proper procedures for installing accessories.
From bowriders to express cruisers, boats have dozens, possibly scores, of holes. There are holes for water pickups, drains and transducers, and above the waterline for bilge outlets, air-conditioners and exhaust. And the deck? Fresh from the cut-and-grind booth it looks like Swiss cheese. There are holes for cleats, tow eyes, grab handles, speakers, lights and more. And that’s on a brand-new boat. Why should you fear drilling one or two more?
Well, because problems can happen when good holes go bad. We’ve cited the serious consequences, but there are other risks. Gelcoat can spider-crack or chip; electrical wiring can be damaged; you may even accidentally drill right through the hull side.
“Measure twice and cut once,” cautions Regal plant manager Mark Vahle, echoing an age-old construction adage (the flip side of which is “measure once and curse twice”). “Verify what’s behind the hole you intend to drill,” Vahle says. “You don’t want to think you’ve got two inches before you hit the hull side and discover you’ve only got one. Fiberglass repair costs a lot of money!”
Drill, Baby, Drill
What are the proper tools? You need two: a drill and a jigsaw. Standard drill bits will do for holes under an inch in diameter; for larger cutouts, use a bi-metal hole saw. Use sharp, fine-tooth blades. Coarse blades will grab and chip the gelcoat. Masking tape provides good protection. Use it to cover the boat’s surface at the area to be drilled or cut.
Placement is critical. Regal uses pre-made templates with pre-drilled holes. Workers put the template in place to drill with confidence. You can make your own templates out of plywood by tracing the part pattern and then drilling through. Clamp your jig in place, and critical alignments are virtually guaranteed.
You can also use a simpler template. Many items, like cleats, may come with a paper or cardboard template to follow. If not, make one of your own, or use the piece you’re installing to carefully mark the hole pattern.
To ensure that your bit stays put at the center of a hole when starting the drill, punch a small nick in the surface with an awl first. It prevents the bit from skipping.
Here’s another tip. Rather than drill through the entire depth of the material, Regal techs drill partway through, then stop to pop the “plug” from the cut out of the saw. Once clear, they continue. Cutting in stages prevents “plugging up” the hole saw, a problem that plagues home mechanics.
Cutting a square hole? Use your jigsaw. Mask the area to protect the gelcoat. Rounded corners prevent stress cracks, so drill the four corners, then use the jigsaw to connect the dots. If you must cut a right angle, use a knife to score an arc around the corner first. Should you start a crack, it won’t spread beyond that line. Likewise, countersink screw holes to avoid starting a crack.
“Gelcoat has no flex,” Vahle explains. “Even a small crack tends to travel over time.”