I've had difficulty finding the "correct" answer regarding "What are the
shaft and prop zincs protecting?" Most people agree that they protect the
shaft and the prop, but what about the engine or the other metal through
hulls? What about the keel, and mast?
I installed a shaft coupler isolator (for vibration dampening) which
suggested a jumper wire across the coupler "if needed" to restore
electrical continuity between the engine and the shaft. I've repeatedly
asked various resources, "When would it be needed?" with no consensus and
little or no scientific or regulatory explanation either way. I don't
currently have a jumper installed. I'm quite confident that I my anodes
protect exactly what they are supposed to protect, the shaft and the prop
and nothing else.
If I were you, I would disconnect various ground and bonding paths and
measure the voltages across the connection. There is really only one
acceptable reading. 0.00 volts. Anything else means that current is
passing through that particular ground/bonding wire to the bonded item and
then through the water around the boat to another underwater item. Check
for both AC and DC volts. You might start with the shore power ground
wire. Easy as unplugging and then check voltage between the outlet ground
and the plug. Then move to the shaft ground brush. Then separate your
shaft coupling. Each step looking for volts across the newly disconnected
pieces. That should prove or disprove a stray current problem. If current
is found then reconnect and move down the line until you isolate the
problem to a sub-circuit or component. Remember there are unexpected
ground connections in waterheaters, computers, microwaves, battery
chargers, inverters, TVs, antennas, light fixtures and pumps. Pretty much
anything with a metal case mounted with metal screws, or interconnected to
anything else besides power.
If no current problem is found then consider using larger anodes, more of
them, or less active anodes.
Good luck,
Josh Muckley
S/V Sea Hawk
1989 C 37+
Solomons, MD
On Sun, Sep 30, 2018, 4:00 PM Chris Hobson via CnC-List <
cnc-list@cnc-list.com> wrote:
> I seem to be burning through zincs on my prop shaft, replace them at least
> twice or more in a season. I posted a photo previously in the group of a
> shaft brush (https://drive.google.com/drive/u/1/my-drive) someone helped
> me figure out what it was. Currently the wire on it leads nowhere which got
> my started on this goose chase, researching shaft brush’s and bonding
> systems.
>
> Anyway my question is should I be connecting the wire coming from this
> shaft brush to a DC ground? Or will that simply connect the stray current
> from the dissimilar metals (bronze prop, steel shaft) outside of the boat,
> to the engine “earth” and start to corrode the engine?
>
> I’ve got AC shore power but had a Galvanic Isolator installed, so I’m not
> sure where the stray current is coming from or what is eating through these
> zincs so quickly. If anyone has any ideas or has had a similar experience
> with burning through zincs or bonding systems, and found a solution (other
> than changing zincs more frequently) please let me know!
>
> Chris Hobson
> S/V Going
> 1980 C MKI
> Hull 615
>
> Vancouver BC
>
>
> ___
>
> Thanks everyone for supporting this list with your contributions. Each
> and every one is greatly appreciated. If you want to support the list -
> use PayPal to send contribution -- https://www.paypal.me/stumurray
>
>
___
Thanks everyone for supporting this list with your contributions. Each and
every one is greatly appreciated. If you want to support the list - use PayPal
to send contribution -- https://www.paypal.me/stumurray
