After some advice here. I have a few sections on the boat where the original bog used (probably something containing asbestos) has fallen off. We are talking about an area, where the top fiberglass section is joined with the hull fiberglass section. Part of the issue is it is hard to reach and it will be hard to properly perpare. What do I use?

#1 Builder's bog
#2 Epiglue
#3 Kneed it epoxy fix/filler
#4 Sealant adhesive

or something else?

Originally probably polyester resin thickened with talc (which has been known to contain asbestos) which is pretty much the same as automotive bog. That stuff is weak, brittle and doesn't adhere too well to old glass. Best equivalent for repair is epoxy thickened with something like fumed silica. Having said that, if the filler isn't actually doing anything other than sealing a not too large gap, then polyurethane sealant should do just fine.

Need photo 73 to give more detailed answer