Water in transom

I recently bought a 14ft fiberglass hull (will post pictures soon). The hull is a 1969, and i am unable to find a name. I plan on rebuilding the boat from the bottom up. As i started grinding and cutting away i removed an old rusty screw from the outside of the transom. After removing the screw maybe a couple ounces of water slowly came out. I expanded the hole to about 3/4" to help let more water drain and drilled a few holes around the area. It is just a small area in the transom that seems to have water damage. The majority of the transom is dry and sturdy. Any advice? Should the whole transom be replaced?

 

So I started picking apart at my transom a few hours ago... I was wondering the best way to get this thing out with doing the least damage to the old wood and glass? I would like to save the wood to trace out a new transom. I ripped off most of the glass on the inside, popped out the drain plug, and much of the glass from the outside of the hull is de-laminated from the transom. I have never replaced a transom on a fiberglass boat, any advice? tips? materials for new transom?

What I'm working with so far...

 

thanks for the input. got the old transom out and will be putting new one in after finishing some sanding and grinding