I have all the old sealant cleaned off both parts and ready to reseal it, but unsure of the best product to use for this.
I used West Marine clear silicone to install new glazing in my ports because it was the only clear silicone I could find that clearly stated that it had UV inhibitors. I and had leaks this summer, just two seasons later. The joint looked tight but, on close inspection, I could see that the compound had separated from the aluminum frame.
I routed out the grooves at the sides and put in a new bead of the same stuff. I can't think of anything better to use if I redid the whole job. It's expecting a lot of anything to remain tight with the different expansion rates of aluminum and plastic and the sun beating on the joint all summer long. Think of the temperature swings from hot summer to below zero in winter.
I had covers made for my hatches to greatly limit the sun UV exposure. If leaks develop again, they will also be on board to stop the annoying drip. I have a friend who can make beautiful covers with proper measurements.
