I had a mate look at my boat with dual batteries. He did'nt like the way I earthed to the hull. Said its wrong. People do things a different way but is there an actual true blue, aus standards sheet, on how to wire dual batteries in an alloy boat. Scruff
Scruff Your friend is 100% correct. The boat should never ever be used as the earth.
Boats are not like cars , especially older model cars where the earth went to the body.
The main issue is electrolous , being alloy it's supprising the boat is not corroding away.
Suggest this is corrected ASAP
In respect to an Aus standard , not that I'm aware of as basically there is no rocket science in wireing a boat. In brief , neg & pos wireing runs from the battery to terminal blocks , normally mounted up near (under) the dash & the various electrics connect into those blocks via switches.
this is fairly standard practice by most pressed alloy boat manufacturers. I spend a lot of my time rewiring 2-4yr old boats especially pressed tinnies. No boat should ever earth to body as Grex said also is destroys wiring extra quick. wiring should only ever connect to a battery in an ideal world. Also if i was you I would check the whole circuit electrical tape should not be used on a boat nor should many other things they do. everything soldered no plain crimps without solder not heatshrink without sikaflex or liquid electrical tape under it (unless hot glue infused)