As long as you roughed up the area either side of the crack by doing some grinding & spanned the crack by an inch or so either side, you should be good.
The great thing about working with fiberglass is you can grind out your mistakes & start again. Great stuff to work with once you get past the initial fear of using it & get the hardener part down.
It is not a trailer front cap but, with the help of an experienced friend, we built this top from scratch.
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Almost a months work to build it. The time was creating the mold.