I remember seeing some pretty frightening gaps when we first put the bow transom into place during our PMD build, which we were able to resolve.  Try taking the bow transom back out, loosening the plank ties a bit further aft, and then carefully retighten the plank laps, working your way back toward the bow.  The main trick is to make sure the top edge of each plank gets seated solidly into the rabbeted lower edge of the plank above.  If something gets the teensiest bit off that way in the middle, the effect will be greatly magnified by the time you get to the bow.  Tighten up by degrees, working your way forward in multiple passes, giving everything a gentle twist and shake from time to time to make sure a plank edge hasn't "stuck" short of its mating spot.

The bow is trickier this way than the stern, probably on account of the extreme rocker.  The main thing is not to despair while you have a sitdown in the "moaning chair" with a cup of coffee in your hand, the manual in your lap, and a prayer on your lips to get yourself bucked up for another go at it.  <;-)

.....Michael