In April I surveyed a Sea Tiger Ketch. The main mast chainplates were glassed in.
I used Thermal Imaging to inspect the chainplates, along with visual inspection. Signs of corrosion were sighted weeping from around the bolt on one of the chainplates. Thermal Imagining helped determine the extent of the corrosion and moisture. The photos below are from that inspection. The last photo was sent by the owner after removing some of the fiberglass. Note the corrosion.