Paddle shortening??

    After a resent paddle at a local lake, my daughters first on a kayak of her own, I drove off and left her youth paddle at the launch. By the time I realized my mistake and returned it was long gone. I am anxious to get her back to where she can actually use her Xmas present so she needs a new paddle. Initially I was going to buy a new 210cm paddle for her. But, decided I might be able to shorten one of my back up paddles turning it into a one piece and save my $ for other things. I have a 240cm fiberglass model that is fine, but I don't like it well enough to use it for anything other than emergency backup. I am asking for any advise on what to cut it down with, what to "dowel" it with, and what to fuse it together? If anyone has tips on how to avoid issues like a wobbly union or water seepage. The kayak is 8'11" long  24.5"wide and she is 53in tall if any one has thoughts on properly sizing it for her I would appreciate input on that as well. I used the search function and know there has been some discussion of broken paddle repair, I apologize if the question is redundant.
  -Amos

 Pull the catch out of the female end, cut it to length, sand the cut edge, drill a hole, and reinsert the catch.

Make sure to use masking tape over the section you are cutting to prevent splinters. 

And if that doesn't work I'm sure I have a couple 210's around here.

Make sure to use masking tape over the section you are cutting to prevent splinters. 

and drilling gorilla tape

Thanks very much guys! I have a few ideas and think this is a worthwhile project. I can't wait to get it started. I daydream about kayak/fishing all day at the hardware store. Rob, it's nice to know that if I can't get'er done that Uncle Rancid has her back.