I've been working on a Petrel for almost a year now and have the deck and hull joined. Last weekend I did the end pours. 6 oz epoxy with microballons in each end. Prop the boat vertical with the end in a bucket of cold water to keep it from overheating. One end in the morning and the other in the evening. When i laid the boat back down I realized there was water! inside the boat. I spoke with Joey and he said that sometimes water can get drawn in through minor gaps in the end of the boat. Wierd! I then drilled the holes for the carry toggles and in the stern water rushed out and there was a big voids in both end pours. I dried it out, taped one side of each hole and am now in the process of filling the voids.
Lesson learned..Smaller end pours or do them in stages so they don't get hot. Or, put a plastic bag over the end of the boat before dunking it in the water.