@Andreyyy I've had surf tabs installed on my boat in the same way @jtryon described for a couple years now as well. I've had no issues with anything coming loose, leaking or anything else. I used 1/4-20 screwed in my first install and I plan to do exactly the same thing in my current project.

@Andreyyy i've had my version of surfgates on my boat for years now with stainless sheet metal screws and 3M 4200 for sealing. pre-drill the mounting holes with the recommended drill bit for the size screw you're using, just like you would do on other mounting surfaces. dip the tip of each screw in 3M 4200, then hand-thread them to make sure the screws bite correctly and don't get overtightened. but first, measure 100x, drill once! make sure the gates are in the position you want, as it would be a pain to have to fill in all the holes later and re-drill.

Thank you very much for the detailed information!

so i have taken this as my next upgrade and i could use some help i have all the parts but i used the cheaper sensors and i need help with the programing of the arduino as im getting lost in the code

Hey @aquasmiths sorry I never got back to you on this. I’ll have to take some measurements and get back to you if you still need them? Hey, I just used 3/4” screws into the hull, no backing plates. These are regular stainless steel screws, not self tapping. I believe they were Hillman #14 oval top sheet metal screws. This is how the boats are done from the factory. You have to pre-drill the holes in the gelcoat by running a drill bit backwards through the gelcoat first and then forwards into the fiberglass, try to avoid drilling through if possible. Running the bit forwards through the gelcoat will chip it. Once the hole is drilled I then took a larger bit to counter sink the gelcoat running it backwards to avoid any gelcoat cracking from the screw going in. Very important to follow those steps as to not crack the gelcoat when the screws go in. Seal each screw with 3M 5200 sealant.