wood rot on outer and inner keelson of old wood boat

[jennyo]

I have rot on my old wood boat keelson just above strut and at rudder port.
the problem is that the inner and outer keelson runs from the bow to the transom.
the garboard plank butts up against outer keelson.
can this be repaired by with new wood pieced in.
or does the whole inner and outer keelson need replaceing
thanks for any information
jennyo

 

[Woodonglass]

What kind of boat? Got any Pics? It's hard to give advice when we can't see what you see.