Yes, that's about 8 inches of water over the floorboards! The owner lives out of the country. It took a while before we could track down someone with a key to the boat.
We have a number of liveaboards here who watch after one another's boats, but this seemed to happen very quickly, although the source of the leak is still a bit of a mystery. It appears that the boat has a bit of a continuous leak, and the shorepower was either turned off or a breaker tripped, and once the bilge pump drained the batteries, down went the boat.