Re: exposed fglass on the keel due to beaching a concern?
To the OP "its a marathon" the above Iboat member was so knowledgeable about boat construction he told you it was ok to beach your boat, don't worry about the fiberglass its "2 inches thick". The next day its 1/4 inches thick, now he is scrambling for someone who has hands on experience with boats. He should have known something about the subject before he ever told you it was ok to beach your boat with no concern for the fiberglass. This is not the way to teach a new boater.
Use a keel guard BEFORE doing this to your boat and you'll be ok. Beware when looking at a boat to buy that a keel guard may have installed over an already worn away or damaged hull. Good luck
Geez. Give it a rest. You made your point already.
As for the original post. If the gel coat is worn off, no big deal as long as the underlying fiberglass is solid. From the description:
"The glass feels very smooth and there are no punctures in it that I can tell."
I would say that the fiberglass has not been damaged to the point of worry. Also, the keel is generally one of the thickest parts of the boat. The fiberglass is the structure, not the gel coat. If this is the case, I would not even worry about it and throw a keel guard on it and be done. Of course pictures would help everyone to make a better assessment of the situation.
As for fiberglass absorbing water. Yes it does, but unless there is a void in the laminate the quantity of water absorbed is not enough to cause a problem, especially for a trailered boat.