Navi/GPS ripping screws from flooring

[Extremeboating]

I have a Garmin 126SV mounted on the bow of my boat it's mounted on top of a TH Marine Kong bracket and with all the bouncing and duty the boat sees when it's out on the water it keeps ripping the screws out from the wood decking. I tried using slightly more coursed same sized screws than the OE ones in the two spots they were coming out of and it seemed like all was okay, but on my boating around today it appeared that it persisted in almost all of the bottom screws of the front bow panel (which is where it screws into the wood part of the decking).

I don't know what the hang up here is and why it keeps doing it. I'm looking for some suggestions here. Perhaps the screws are just too short or something, but I was thinking getting longer screws in general so instead of the OE 1" I would get 2" screws so it bites into and past the entire deck, and maybe going up to #10 screws instead of the #8 OE ones which are screwed into the deck. I don't know if that would be more of a band aid fix or if that would suffice for the issue.

Anyone got anything else? Here is a photo for reference so you can see the area I'm describing and how it's mounted.

First photo for reference of the bracket so you can see exactly where it sits beneath the nav itself:

20210429_160711_optimized.jpg

What it currently looks like:

20210507_144417.jpg

[MikeCSr]

Since that entire front panel can easily be removed, I would suggest that you use stainless machined screw with locking washer and large flat washer and nut on the underside of the panel

[@Reel_Chris]

That's a lot of weight working with leverage against a few small screws. In addition, plywood is terrible at holding screws. You're better off adding some metal, plastic or treated solid wood underneath the deck and then bolting the unit through the deck and the backing material with washers and lock nuts. You can find aluminum square tubing and PVC sheets at home depot. Both would probably work well and last forever.

[Extremeboating]

Thing is, when I remove that panel I don't want the nut to fall l beneath the deck. Hmm.. perhaps a spot of 5200 on the large washer which will be beneath the nut itself to keep the washer and nut in place huh? I'm just trying to keep it as "idiot proof" as possible.

[Lightning 6]

Move the bracket aft 2 inches and thru bolt it through the plywood using a backing plate.

[bassfisher444]

That panel is aluminum not wood, screws don't hold very well in aluminum, I have my mount screwed to the wood floor and haven't had any issues.

[Extremeboating]

That panel is aluminum not wood, screws don't hold very well in aluminum, I have my mount screwed to the wood floor and haven't had any issues.

Do you have a photo of your setup? I have an idea of what it looks like, but I just don't want to deal with anymore tearing anywhere, so it would be best to see what that looks like at this point.

Also, what size screws did you use to secure the bracket down? 1.5" or 2" ?

[Topwater 2]

Nuts and bolts are my vote.

[Extremeboating]

Nuts and bolts are my vote.

That is the simplest way I agree, but I'm not sure if I have sufficient access across the panel below the deck despite my foot pedal panel plus that doesn't resolve the issue if I go to remove the panel the nuts may fall out from under.

[Extremeboating]

You know what, there is something here I didn't think of as a solution. Below the deck assuming I have access across the beam of the deck I can use tee nuts and a small dab of 5200 on each screw to prevent them from backing out. I'll pick up traditional nuts and washers in the #10 variety and their respective bolts in 2" and then I'll also pick up some tee nuts and determine which would be best to use once I'm under there. Either solution should work but the tee nuts will stay in place long after I remove the screws every time and be a permanent fixture below the deck without damaging the wood because of the small claws they use to keep them in place.

[mikeky]

Remove the panel and see if you have access. If so use 1/4" stainless bolts, nuts and fender washers. If you can find some flat aluminum to use as a backer plate do that.

No need to worry about losing your nuts.

A #10 screw is not big enough.

[bassfisher444]

Do you have a photo of your setup? I have an idea of what it looks like, but I just don't want to deal with anymore tearing anywhere, so it would be best to see what that looks like at this point.

Also, what size screws did you use to secure the bracket down? 1.5" or 2" ?

I think I used 1 1/4" screws. 20210414_165415.jpg

[Extremeboating]

As an update I did have full access to the front with some maneuvering around after pulling the recessed tray and I used 5x 2" long 10-24 bolts, and 5x 10-24 tee nuts. I pulled the bolts after I installed to see how they fared out and the nuts never fell out. With a physical pull out strength of 1850 lbs they hold the panel insanely well. Zero movement out of the entire panel now. Thanks for the insight guys.

[MikeCSr]