Thanks fiddy, I thought of that stuff as well. I am not sure if my cowl is gel coated or not. Its from carpy and is black??
If it's a glossy surface like a new fiberglass boat it's probably gel coated If it's the underside and rough textured probbly not. It still doesn't hurt to rough it up (both metal and fiberglass) and have as much surface to surface area.
The one thing about gorilla glue (polyurethane) is it
expands and has potential to make a big mess. It's kind of like the polyurethane foam. Depending on the application, for stuff that doesn't necessarily have to be looked at I like to have a little bit of excess foam out the sides. As it swells it gets to a point just past where it is goop and turning towards solid and tacky- close about an hour usually. When the surface starts to get a crust I like to continue to squish it back towards the joint. Doing this makes it more dense and solid instead of frothy when it hardens.
Play with it a little bit before you do your project. Practice glueing a couple things together is the best way I can think of to learn what it will do.
