Wow Jim, that is a lot of silicone. Mine is no where that thick and wide.
Your picture is why they shouldn't sell silicone to idiots.
If a little doesn't stop the leak, put some more on, then some more, then some more, and when that still doesn't stop the leak, blame the silicone. (But put some more on just in case}
In my 70 years I've never run across a situation where silicone was the answer to a leak or a good method to seal any thing.
What I'm trying to remove is some sort of sealer that looks like it was meant for flat horizontal areas, and was used on the vertical sides and it ran down in long streaks.
Of course the person who did it, didn't bother to clean off the areas where it ran down. And now the streaks have yellowed and attracted dirt
Also when I started, for some reason I thought the entire coach was covered in aluminum, never really paid any attention to it.
So the first parts I used Motsenbocker Lift Off on were the fiberglass sides and it did a good job.
Then one morning I decided to clean the cabover front and that's when I realized that Motsenbocker Lift Off made a good paint stripper.
I'll still use it on the fiberglass