My SSB has the ground connected to a Dinaplate. The Dinaplate was connected to the bonding system of the boat and I discovered after 5 years that the bonding system was also connected to the engine at the transmission.

I know that it's not the way to do it but it worked fine with no problems in either the SSB or the boat.

I took the engine out of the loop and found no difference so I left it that way.