Size of Transom Zinc
I own a CHB 42 Sedan and we boat on the Great Lakes. I have a zinc on
each shaft and each rudder. I notice most power boats have a zinc on the
transom too. I'd like to know what size zinc should I have on the transom?
Thanks
Stephen Hill
Lady Royal
Toronto, Ontario, Canada
The zinc you are seeing on the transom of some boats is tied into a bonding
system. Just putting a zinc on the transom would do nothing by itself.
Jim Alexander
----- Original Message -----
From: "Stephen Hill" shill63@cogeco.ca
To: trawlers-and-trawlering@lists.samurai.com
Sent: Friday, December 23, 2005 3:52 PM
Subject: T&T: Size of Transom Zinc
I own a CHB 42 Sedan and we boat on the Great Lakes. I have a zinc on
each shaft and each rudder. I notice most power boats have a zinc on the
transom too. I'd like to know what size zinc should I have on the transom?
Thanks
Stephen Hill
Lady Royal
Toronto, Ontario, Canada
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Stephen,
First and foremost, since you are boating in fresh water, none of this
applies much. Apparently, your boat is not bonded, or the zinc for the
bonding system is elsewhere (sometimes they are on the hull). Most
likely, you don't have a transom zinc because your boat is fresh-water
rigged and has few if any zincs. Some fresh water only boats don't even
have a heat exchanger; they just run the fresh water through the block,
manifolds and out exhaust system, with no zincs anywhere. We used to
boat in The Great lakes and most boats we encountered there were like
that. Ours, a Bayliner, was "converted" to salt by adding some zincs
and a heat exchanger.
Anyway, I digress. The zinc(s) you see on the transoms are the anodes
for the bonding system. On the inside of a bonded boat, one or more
heavy copper straps will run the length of the boat and wires (properly
green in colour) will be attached to underwater metallic components.
The copper strap(s) end at the transom zinc. The theory of this is,
connecting all the underwater components together will put them all at
the same potential, and the zinc will protect them collectively from
galvanic erosion. In North America, this is common practice.
As well, some people bond other large metallic objects to the system,
such as engine blocks and fuel tanks. This is done to provide a
counterpoise for HF radio installations.
But, it is a hotly debatable theory. In Europe it isn't as common.
European boats generally have individual zinc protection on certain key
components or even no protection at all. They don't sink in droves!
One of the down-sides to bonding is that the wire between the hull
fittings sets them up as a battery with a heavy load (the copper strap
is a dead short and the fittings will undoubtedly vary in metallic
content). The other is that the transom zincs provide greater
protection to fittings that are closer.
You may not want to bond some items, for example, your thruster. If
your thruster is bonded then the little zincs on it are connected to the
overall system. The more forward hull components will derive more
protection from them than from the transom zincs, and they will be
eroded much more quickly. So, generally, thrusters should not be
included in the bonding system (now there's a statement that will start
a discussion!).
I could go on, but the subject has been covered ad nausium on this list
and a Google search for galvanic corrosion or boat bonding should turn
up plenty of grist for your curiosity mill.
Cheers,
Maurice
-----Original Message-----
From: Stephen Hill [mailto:shill63@cogeco.ca]
Sent: Saturday, 24 December 2005 09:53
To: trawlers-and-trawlering@lists.samurai.com
Subject: T&T: Size of Transom Zinc
I own a CHB 42 Sedan and we boat on the Great Lakes. I have a zinc on
each shaft and each rudder. I notice most power boats have a zinc on the
transom too. I'd like to know what size zinc should I have on the
transom?
Thanks
Stephen Hill
Lady Royal
Toronto, Ontario, Canada
http://lists.samurai.com/mailman/listinfo/trawlers-and-trawlering
To unsubscribe send email to
trawlers-and-trawlering-request@lists.samurai.com with the word
UNSUBSCRIBE and nothing else in the subject or body of the message.
Trawlers & Trawlering and T&T are trademarks of Water World
Productions. Unauthorized use is prohibited.
<I own a CHB 42 Sedan and we boat on the Great Lakes. I have a zinc on
each shaft and each rudder.>
<Some fresh water only boats don't even
have a heat exchanger; they just run the fresh water through the
block,
manifolds and out exhaust system, with no zincs anywhere. >
Stephen;
Just out of curiosity, and to further enliven the ongoing thread: how
often do you find it necessary to renew your zincs in the freshwater
environment?
Terry
Tamarack
Actually, they shouldn't be "zincs" in fresh water... they should be
"magnesiums".
Keith
Do not eat natural foods. I used to eat a lot of natural foods until
learned that most people die of natural causes.
----- Original Message -----
From: "Terrence Neill" tsneill@centurytel.net
Just out of curiosity, and to further enliven the ongoing thread: how
often do you find it necessary to renew your zincs in the freshwater
environment?
Snip
Actually, they shouldn't be "zincs" in fresh water... they should be
"magnesiums".
Keith
Hi All
Correct Keith, and as a European boater I can assure you all that we take
galvanic corrosion very seriously. I know of no serious boater who would
neglect the protective anodes and to do away with them altogether is heresy.
But you know, it appears that you can do everything possible to protect your
own boat but the anodes' effectiveness and longevity may depend on your
neighbours' as well.
Look at "products" on this site to learn more.
http://www.sterling-power.com/
Best regards and a Happy Christmas
Roger Bingham
Stevens 1140
France