Cal 2-30 bulkhead repair

[Painter]

I need to repair a dry rotted port side bulkhead which holds the chain plate for the upper shroud. Would appreciate suggestions on type of saw to use,technique for making template, methods of checking for rotted areas,methods of fitting new scarf shape in place,fiberglassing types and techniques and any other related suggestions.

The boat is a 1969 Cal 2-30, a beautiful classic

Thanks in advance for any hints,

Painter