Connections to ground plate in 'glas hull?

I'm re-wiring a 60s vintage 'glas-hulled cabin cruiser. There is a metal plate attached to the hull with two large terminals on the inside of the hull. At present, only the gas tank is bonded to this plate. Should the -12V terminal of the battery (thereby all NEG side wiring) also be bonded to this plate? If so, what gauge of wire should be used?
Much obliged for any help...

Re: Connections to ground plate in 'glas hull?

Ayuh,... The motor's block is bonded to the bonding plate, Not the Battery....

Re: Connections to ground plate in 'glas hull?

So now I'm curious, are boats different from cars in that the negative ground does not include the engine block?

Re: Connections to ground plate in 'glas hull?

I'm curious too... if you start bonding some things and not others (ie all metal through hulls, seacocks, batteries, electically related or not) arn't you opening yourself up for galvanic corosion if there are stray currents outside or inside the boat?

I read a book that had a couple chanpters on bonding and corrosian issues a while back, and if I recall correctly there are two schools of thought... one says bond every metal object, and one says float everything to prevent current flow.

Then lightning protection is a whole new complexity to add to the mess...

This is a complicated and potentially complex topic that I'm not qualified to give advice on, so I'll just say "research".

Re: Connections to ground plate in 'glas hull?

I have always made sure to bond everything to - well. I even added another bonding plate under my dash to accommodate everything neatly.

Also, I have always assumed the block bonded through the starter connections and then through the drive to the anode(s). I'll have to pull my doghouse and look again.

I'm still learning the more complex areas of this and would appreciate knowing whether I'm wrong or not.

Re: Connections to ground plate in 'glas hull?

big difference between bonding and an engine ground.
bonding simply holds all metalic objects that are mounted in that insulator to the same electrical potention.
also make sure any metal fuel tank fill necks are bonded to the metal fuel tank.
typically the bonding plate wire is bonded to the engine block.
the reason for NOT using the -battery terminal as a bonding wire point is simple.
the average -battery to block ground is about 4Ga, the typical bonding wire is 10Ga.
we dont want to use that 10Ga as a ground for the engine,especially starting, in the event of a battery to block ground wire failure.
tends to let the smoke out of the wire.

Re: Connections to ground plate in 'glas hull?

I am assuming the OP is talking about a sacrificial zinc that would be used for bonding underwater fittings, engine parts, anything that comes in contact with raw water. But the fuel tank bonded to a zinc plate tells me otherwise. Maybe a "wunder bar", the underwater ground plate?