On Wed, 08 Sep 2004 08:17:40 -0400, Jonathan wrote:

Because of a miscommunication with the yard, my Alberg 35 was relaunched
after a haulout for bottom painting without replacing the zinc. I had
taken the old one off (not much left).

Years ago I had a friend drop a fish shaped zinc overboard every time he
came back to his slip. It was supported on a line for the weight, and a
wire from the zinc to....actually I don't remember what it was to, but I
think it was the green wire grounding system on the boat.

If I adopt a similar plan, attaching a wire to the zinc that did not get
mounted and attaching the other end to engine block or shaft, will this
suffice sufficiently until my next haul out? which will not be until
2006 probably....



I believe that the effectiveness of a zinc diminishes somewhat as distance
from the protected metal increases. So you probably want to hang the zinc
pretty close to the prop. I'd use galvanized steel wire to suspend the
zinc. Above the water line, you can switch to copper wire, but make sure
you have a good connection at the junction. Don't let the junction get
wet, and inspect it periodically. Either way, inside the boat, connect the
wire directly to your prop shaft if you can, or some part of the
transmission which is electrically connected to the prop shaft if you
can't. Again, make sure you have a good connection, and try to keep it
dry.

Of course, if your prop is a different metal than your shaft, this may not
be a great idea, either, because it will guarantee that you have current
flowing through the prop/shaft junction. Even so, I think the zinc will
protect the prop. And really, it's no different than mounting the zinc
directly on the prop shaft anyway.

I am concerned as the boat had been in since August 2002, and the zinc
on it was almost completely gone. The boat spends May thru October on a
mooring then November through the end of April at the dock for the
winter.

Thanks,

Jonathan

As others have suggested, your best bet is definitely to get a diver to
install the zinc. I have installed shaft zincs under water before,
although I did it in nice clean, warm, clear water. ;-)

As a side note, theoretically, you can pretty much neutralize your slip by
running a heavy gauge wire around the sides of it, and running a short
pigtail into the water at all four corners. The pigtail should be
galvanized steel wire connected to a reasonable sized zinc at the end. The
pigtail should be long enough that it either almost touches bottom, or is
much deeper than the draft of your boat. This will short circuit any
electric field which might otherwise try to exist in the water near your
slip. You can tell which way the fields go, if they are DC fields, by
seeing which zincs wear out faster.

Note that I've never tried this, but I would like to. If I ever have a
boat again I probably will, just for kicks. I'll still put a zinc on the
prop shaft, though.

--Mac

"Mac" wrote in message
news

I believe that the effectiveness of a zinc diminishes somewhat as distance
from the protected metal increases. So you probably want to hang the zinc
pretty close to the prop. I'd use galvanized steel wire to suspend the
zinc.

Uhm, what do you think would happen to the zinc coating on the gavanized
wire?

Meindert

Several comments here.
I don't recall him saying he had it on his prop?
Might be on his skeg?
Might just be on his trim tabs?
Regardless, it's foolish to not get it on real quick.
Good point Meindert but cray fishermen here in Ozzieland use galv wire to
tie anodes on the pots which are made out of steel & stainless mesh.
Everybit comes out sparkling until the anode is gone.
BruceM


"Meindert Sprang" wrote in message
...
"Mac" wrote in message
news

I believe that the effectiveness of a zinc diminishes somewhat as
distance
from the protected metal increases. So you probably want to hang the
zinc
pretty close to the prop. I'd use galvanized steel wire to suspend the
zinc.

Uhm, what do you think would happen to the zinc coating on the gavanized
wire?

Meindert

On Thu, 09 Sep 2004 17:30:38 +0930, BruceM wrote:

Several comments here.
I don't recall him saying he had it on his prop?
Might be on his skeg?
Might just be on his trim tabs?

You're right. I'm jumping to conclusions.

Regardless, it's foolish to not get it on real quick.

Agreed.

Good point Meindert but cray fishermen here in Ozzieland use galv wire
to tie anodes on the pots which are made out of steel & stainless mesh.
Everybit comes out sparkling until the anode is gone. BruceM


[Meindert's message snipped]

Yeah, the wire doesn't need 100% zinc cover. As long as there is zinc
anywhere near it (and electrically connected), the wire will be protected.
And I imagine that once the anode goes, the regular steel will serve as an
anode to the stainless.

--Mac

On Thu, 09 Sep 2004 08:06:35 +0200, Meindert Sprang wrote:

"Mac" wrote in message
news

I believe that the effectiveness of a zinc diminishes somewhat as distance
from the protected metal increases. So you probably want to hang the zinc
pretty close to the prop. I'd use galvanized steel wire to suspend the
zinc.

Uhm, what do you think would happen to the zinc coating on the gavanized
wire?

Meindert

Well, as far as the water is concerned, everything in this system looks
like zinc. So in the absence of stray electric fields, there isn't any
strong reason for the galvanization (or anodes) to wear away too fast.

If the electric fields in the water (or time) cause the galvanization
to wear away, then the anode will protect the steel until the anode is
gone. Then the steel will rust. This will be obvious upon inspection, and
can be dealt with by replacing the cheap galvanized wire and adding
another anode.

I specified galvanized wire, as opposed to copper or stainless wire,
because the galvanized wire won't cause the anode to disappear as quickly
as those other metals will. Aluminum wire might work OK, too. But once the
anode is gone, the aluminum might disappear rapidly, and the oxidation
might not be as obvious as rust on steel. I've never used aluminum wire
for anything, so I don't really know what would happen.

Anyway, for similar reasons, never use stainless seizing wire on your
galvanized anchor shackle. Use cheap galvanized wire. The stainless (or
monel) wire some people use actually causes the rode to function as an
anode. Eventually the links near the shackle will rust, long before the
rode as a whole needs regalvanization.

--Mac

Hi,

As a diver who replaces zincs and cleans bottoms among other jobs I will
tell you to get someone to dive your boat and put the zincs on the shaft and
any other places that are at risk. Too often I see boats that have not been
protected and it gets rather costly to repair the damage.

Diving in warm clear water must be nice, I haven't done it in years.

Brian

On Thu, 09 Sep 2004 12:58:19 -0700, Brian Combs wrote:

Hi,

As a diver who replaces zincs and cleans bottoms among other jobs I will
tell you to get someone to dive your boat and put the zincs on the shaft and
any other places that are at risk. Too often I see boats that have not been
protected and it gets rather costly to repair the damage.

Diving in warm clear water must be nice, I haven't done it in years.

Brian


Me neither. ;-(

--Mac