Grounding all through hull (more on Zincs!)

[James Osborne]

All my Spartan bronze through hulls are grounded to a grounding plate which itself is grounded to the engine/shaft/prop.

Last winter I inserted a plastic propsaver between the transmission and the propshaft so now there's no metal electrical connection to the shaft/prop/zinc. They are isolated from all the other grounded components.

Should I run a wire between the transmission flange and propshaft flange to make the electrical connection that the drivesaver prevents? I suspect so but I'd like to hear exactly why.

Bonus. The 1.25" thick drivesaver moves the prop back 1.25" which is just sufficient to install a streamlined collar zinc on the shaft in front of the prop. No need for an expensive "perry nut zinc". I have to cut a slot in the zinc to fit round the key in the propshaft and make it butt up close to the prop so there is still a 3/4" gap aft of the shaft bearing.



josborne@ibl.bm

[chuck yahrling]

All my Spartan bronze through hulls are grounded to a grounding plate which itself is grounded to the engine/shaft/prop.

Last winter I inserted a plastic propsaver between the transmission and the propshaft so now there's no metal electrical connection to the shaft/prop/zinc. They are isolated from all the other grounded components.

Should I run a wire between the transmission flange and propshaft flange to make the electrical connection that the drivesaver prevents? I suspect so but I'd like to hear exactly why.

Bonus. The 1.25" thick drivesaver moves the prop back 1.25" which is just sufficient to install a streamlined collar zinc on the shaft in front of the prop. No need for an expensive "perry nut zinc". I have to cut a slot in the zinc to fit round the key in the propshaft and make it butt up close to the prop so there is still a 3/4" gap aft of the shaft bearing.

I think its a matter of preference: some say you should run a jumper between the engine and shaft to assure the propeller and shaft add to the boat's ground surface, so as to better diffuse static buildup and/or lightning strikes.

I've also read that in some parts of the world (Europe especially) the prop and shaft are purposefully isolated to prevent galvanic activity; a zinc is not used in that case.

If you are on a mooring I would run the jumper and use the zinc for occasions when you may connect to shore power; that's what I do.




cyahrlin@cisco.com