How did I miss this thread for so long? I just measured my P15, and got 21.5 inches for the stem height.
It is a very dry boat in Class II rapids with 2 foot waves, and still maneuvers easily. It appears capable of taking a good sized payload. I would not hesitate to take this canoe on an extended Class II-III trip. I chose it over the Pocket Canyon because it is a more general purpose touring canoe versus a whitewater play boat. At 15 ft LOA and 36" beam, it will not break any speed records. The P15 can serve as either a small tandem for short trips, or as a high volume solo boat.
The biggest negative is that the canoe tends to get blown around by crosswinds when I paddle solo on flat water. Most likely this would not be a problem with a load, and I am still experimenting with seating position and trim.