That's a really good tale. It is instructive. Statistically, most disasters are due to multiple failures. I believe you were very
lucky. You suffered multiple failures and saved the boat. You may not be so lucky next time. Please consider having a serious,
large contingency battery that is NOT connected to anything in a standby state for situations like this......it's cheap insurance.

I use a compressed air starter on my diesel and carry 2, 100 liter tanks of which one is always full and not normally connected
for just this reason. A freind years ago, lost his 60' ketch off Okinawa due to this identical fault. He also used an electric
starter, but when he needed the engine, bilge water had shorted it out and he lost the boat on a corral reef. I use air now, my
engine will snorkle.
Steve