Soft Spot near hull repair advice

I have a 2006 gen 1 Epic V10 Sport fiberglass and polyester resin (club layup) surfski with a soft spot on the side of the boat near the transtition area from the hull to the footwell. I have good experience with glass and resin and if the best solution is to sand off the gel coat and reinforce the area, that is fine. Wish i could do it from the inside though!I am not concerned about aestetics or weight or repair.

Edit: attaching photos.
The stringer is also detached from the hull in this area. Going to reattach stringer and sand down the weak glass causing the soft spot and build the area back up with epoxy and glass. 

You didn't post any  photos or much info, so I don't know, but maybe this can help: www.surfski.info/forum/1-general/19515-w...-fix-this.html#36685

You can't use that way of repairing a club construction, the core used is not hollow and is too thin.
As you said, just sand the gelcoat back to expose the fiberglass and repair from the outside with one layer of carbon and then finish off with gelcoat once cured. 
To make things easier, use peel ply over the repair and then compress the repair whilst still soft with a layer of masking tape over the whole repair. This will make it quite smooth and when you remove the peel ply it will be ready for gelcoat.