Because I had to take things to pieces to check for water damage, I decided it was a good time to rev the main controller board. This was damaged a while ago when the first attempt at waterproof ESCs failed. I patched it up to get it working again and also did a redesign to improve power distribution and add more servo controllers (for the eventual robot arm). I'd put off ordering the new PCB, but now seems like a good time to commit to this improvement.