Attaching an Inspection Port

[high510]

Would you use though deck machine screws with a washer and nut below deck or self tapping screws? TIA

 

[DanB]

Early method was a self tapping screw then self-tappers into expanding inserts and now they use pop rivets. All of these suffer from pullout. A more secure method whether you use screws as you propose or rivets is to include backing washers for broader purchase on the deck. Machine screws with NyLock nuts or rivets are the two popular methods. My repairs have been made using both with equal success. I include backing washers and I seal everything with a light smear of marine sealer like 3M 4200 caulk on the washer face, the screw or rivet shank, and under the fastener head. The factory uses sealed rivets, but if you use regular rivets don't forget to put a drop of sealer into the rivet's center hole.

 

[DanB]

Sorry, I was thinking coaming attachment when I wrote that. Just helped a friend reattach one that day, but the final using machine screws or rivets is still the same method for ports too.