This may be painful to some, so view at your own risk
One of our members (now on eternal patrol) lost his first sub on her maiden voyage. She must have flooded right off the bat. Most of us would have gotten wet at that point, but the captain was in no physical condition for swimming. By the time a rescue operation was mounted, they were unable to locate the boat.
She was recovered 3+ years later when the pond was drained for maintenance.
Ugh, what a mess. Sorry the original owner isn't around to receive it. Even in it's current condition I am sure they would have been happy to get it back. If you decide to rebuild it, get the latest WTC from Subtech, it is much more leak resistant then the original.