Hi Don,
I too had wood rot on the stern quarters of my 1999 IP380. One option if money isn't a concern, is to scarf in new teak. I cut out the rot using a wood chisel then mixed teak dust with the West system epoxy. Use a consistency of peanut butter so you don't have sags. Tape the surrounding areas, then sand to prior level. It has held up quite well.
Sally