Frustrated is not the word
 

When my engine is running and it is shut off sometimes it won’t start. As in no click no anything. Has been happening for years. Today after motoring in I stopped at the fuel dock. Whe leaving the engine again wouldn’t crank click on anything. I flipped the battery switch and it cranks right up. Any ideas.

I'm thinking you have a bad current path from that one particular battery. It could be anything from the battery post to the starter solenoid, every cable, terminal, connection on either the positive or negative side. Maybe even the battery switch itself. It's possible there are multiple issues too so even if you find one problem, don't stop there and call it good. Be thorough.

Had the same problem. Needed new battery cables. Smooth after that