Installing male "screw type" snaps to hull

[smckean (Tosca)]

I've searched around the forum but can't seem to find an answer (what I did find, addressed interior surfaces).

I would like to mount a couple snaps to the outside of the hull, well above water line maybe 12" below the top surface of gunnel where one steps into the cockpit of a CD25. I will also install a couple to the inside wall of the gunnel of the cockpit. The reason is that I want to attach an approximatetly 18" x 36" piece of thin, rubber-backed carpet quickly and easily to that portion of the gunnel btwn the cabin wall and the forward end of the rail. This is where I pull up shrimp and crab traps from the water into the cockpit (as I presume most folks do). I want to provide some protection for the gelcoat in that location.

I purchased a dozen male/female snap pairs and a anvil type setting tool. Putting the female portion on the carpet will be easy, but I'm not sure how to mount the male portion to the hull. This kit I bought comes with screw type snaps with #6 or maybe #8 SS screws that are 5/8" long. Can I just screw those into the hull? Should I drill holes first (overdrill, fill, re-drill maybe)? Is 5/8" too long.....I believe they make male snaps with 3/8" long screws.

[tsturm]

[Robert H. Wilkinson]

You can use any length screw that you need as long as you get ones with a small enough head that recesses into the snap. If the head is too big the female snap will not go on.

Drill hole slightly longer than the screw will reach. You can mark drill bit with tape to correct depth. Screw must thread in tight but do not force. Ream hole a bit if necessary.

Holes in gel coat should be countersunk to avoid cracking the gel coat. I have a countersink bit but you can use a larger drill bit running it in reverse.

I use 5200 to seal hole and threads - also keeps screw tight so it doesn't back out or come loose.

Regards, Rob

[thataway]

I agree with Robert Wilkinson, I will run the pilot drill bit backward before before drilling the hole forward, to chamfer the hole before the bit starts cutting the gel coat.. Go very slowly as you start to drill the hole, with little pressure, Increase the pressure as the hole enlarges--all of this (including the countersink) to avoid cracking the gel coat.

If the screw goes too far into the boat hull inside, use a cut off wheel in a Dremel Tool to cut the screw just a fraction proud of the inside of the hull. You can put a dab of sealant on the end of this, to prevent it snagging any item on the inside.

[croakz]

[smckean (Tosca)]

croakz,

I ended up getting 5/8" screws. However, you probably can't learn much from my experience since, as it turned out, I never did the project. I still have the snap/screw male heads, but I've never actually used them.

P.S. To protect my gunnel from crab traps etc, I ended up just using a cheap shower mat that has a bunch of small suction cups on one side. It sticks the side of the boat and the gunnel just fine.

[drbridge]

For your application you might want to think about trying these

https://www.sailrite.com/YKK-SNAD-White-40mm-Adhesive-Backed-Flexible-Base-Stud

They stick to fiberglass very well and can be removed. Easy application, if you do happen to lose one another can be reapplied easily