Patching A Hull

When we bought our boat we noticed a patch job on the seam, at the very stern of the boat. After 7 years, I've noticed the patch is no longer water tight. I have been looking over some sites for simple ways to patch it from the outside, and I'm wondering what suggestions people may have. I'm leaning towards either JB Marine Weld or 3M 5200. Which of these would you prefer, or is there a better product out there?

without no pics and im assuming your wood on the transom is in front or on top of the leak id remove it before doing any repairs to ensure you fix it once and it stays fixed. 99% of the guys here will tell you to go with the 5200 but if its right where the hull meets the stern jb marine will work fine. i removed rivets and temporarily used regular jb weld to fill them and it has not leaked a drop in a year and a half and the rivet holes were through my hull on bottom and the sides. post a pic or two so we can get a better idea of what your working with.

Consider Weld its a Real FIX ...Unless there's too much burnable stuff in area.Or TOO hard to get at...cva34