I am building a wood 40' sailing catamaran. The mechanical propulsion
will be an outboard. I have read a lot about boat wiring and they all
talk about having a ground connection on the engine block thereby
making a connection to ground through the propeller shaft etc. With an
outboard I will not have a permanant connection to the water ground so
do I need a separate ground connection to somekind of conductive
wetted surface? I have been designing the boat to not have any
underwater metal pieces, do I need one? ABYC and USCG regs talk about
ungrounded systems but not the pros and cons or implications.

fritz