The most important form of lightning
protection is to ground the mast
. When done correctly this provides the safest path to dissipate the energy from the strike.
There is some slight addition protection afforded to metal boats from the faraday cage effect, but I have never heard of someone trying to duplicate this of a fiberglass
A proper faraday cage provides very good protection, but it requires special metals to dissipate the electrical
and magnetic pulse generated by the strike. A copper mesh, particuarly with holes for hatches etc will only do a poor job, even if you can achieve, and maintain, good conduction around the whole of the boat.
Frankly I amazed someone would try to do this and I would not attempt to repair the system.