I would have posted this little data point in one of the many threads praising the toughness of the Shearwater Petrel and its successor, the Perdix, but this is easier. Apparently, this Petrel 2 was struck against some hard surface--maybe it contacted a rock on a shore dive--in just the wrong place, leaving a tiny nick or chip at the rim of the battery compartment, where the battery compartment plug is flush with the case after screwing it in. It wasn't even noticeable until later inspection. A tiny nick or chip. Perhaps that spot is its Achilles Heel. Due to the chamfer or rounded end of the battery compartment, the case does appear to be thinner there. Ironically, in some previous thread I asserted that the Petrel is "built like a tank." Well, perhaps not quite. The Shearwater U.S. repair center informs me that the computer is dead, with a repair estimate of US$400. I still believe Shearwater makes a great computer. Time for a Perdix, it seems.
Did the nick/chip allow water directly in? Or did it cause the O-ring to get damaged when installing the battery compartment plug?