I'm all for stars doing their own stunts but it's hard to imagine why they let Jim and Frank do that sinking boat stunt in the episode where Gomer wins a boat in a jingle contest. It's a great gag to end the episode, but after laughing at first it's almost scary the risks they took in doing it. They're both standing up in the boat and it almost stands up straight before it and their heads disappear under the water out what seems to be a real marina. What if one of their feet had gotten caught or something? Could they really know for sure how that heavy boat might topple? Man that was risky. I wouldn't have done it. I've read Phil Silvers almost drowned in "It's a Mad, Mad World" when he did the bit where his car sinks in the water. This is actually kind of a scary scene, too.
I'd like to hear Jim Nabors memories of it.

I'm sure they had a lot of precautions to insure nothing would happen to them.