Others maybe more qualified than me to anwser this, but after playing around with epoxy resin recently, I bet you could back it inside with epxoy resin, biaxial tape(multidirectional glass cloth, very very strong once resined) and a layer of resin fillet blend (resin paste).
Once that is done you could sand back the top service in the area concerned and apply a resin top coat in that area, sand smooth, paint or gelcoat it.
I have spare epoxy resin, biaxial tape, fillet blend if you want to pop across it probably would not take long.
I would be interrested in hearing from any experts though just in case I'm quoting bad methods, but this approach has built a console that would give a sledge hammer trouble.
How's the Mariner 50, goes well I hope?
PS if need be email or PM me and I will email my numbers to have a chat re using some resin stuff.(no charge, its left overs from my console project)
Diving is Life, the rest is just surface interval.
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Oxygen Toxicity is for Life