As summer is progressing, and having this happen to me on my yami, not sure if it is a fluke or just those wasps liking gray……
Anyway, just watched this video: https://www.youtube.com/watch?v=ef_ys3nIkXo FAST FORWARD TO 5:40 in the video.
The exact same thing happened to me. I found it when the boat was already in the water but at least the water was warm.
Just a warning to take a peek if your boats are sitting outside for any length of time.