Fiberglass Repair on Stern

Being a novice, water was unknowingly allowed to sit inside a hull over an extended period of time after entering through the drain plug. As a result, two large cracks opened in the fiberglass at the corner of the stern and side hull, and a large blister formed on the stern directly below the steel rudder plate. Once discovered, the water was drained from the hull and the drain plug was left open and the hull allowed to dry during the last 8 months including the warm summer months. Recently, a dremel was used to grind out all loose wood and fiberglass from the cracks.

Is it necessary to cut out the entire damaged fiberglass including the blister/bubble and rebuild the stern? Or, is it okay to now place new fiberglass over the damaged area since all of the soft material has been removed down to solid wood and old fiberglass?

Pictures are posted on Craigslist - http://www.craigslist.org/sfc/boa/131875182.html

Any information or suggestions are welcome - Thank you

[img]http://www.craigslist.org/sfc/boa/131875182.html
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Hopefully someone with professional fiberglass experience will post their ideas, but in my humble opinion, the whole stern end of the hull should be cut out. The crack looks bad but that sway, or blister, in between the gudgeon and the drain plug looks serious as well. I don't think it would be too much work to fix this, you could cut the stern out with the dremel then screw in a temporary marine plywood stern cut to fit exactly so that the outside of the wood is flush with where the stern would be. Use this wood as a mold to build new fiberglass around using west system cloth and epoxy. You can integrate it into the hull and just cover over the screws with fiberglass cloth and more epoxy. When it hardens up, paint and re-apply gudgeons and drill a hole for the drain plug assembly. The repair will be stronger than the stern ever was in the first place.

jrg