Corrosion with Volvo outdrives
Dennis J. McTigue
Duoprop outdrives. These have stainless steel props and the boat is a
Regal Commodore 322. The Volvo and Regal reps can't seem to get it
fixed. Anyone else had this problem?
__
Dennis J. McTigue | Internet Address: McTi...@OSU.EDU
College of Dentistry | 305. W. 12th. Ave. Columbus, OH 43210-1241
Ohio State University | Phone (614) 292-4250 FAX (614) 292-7619
Michael J Porter
Dennis J. McTigue <mcti...@osu.edu> wrote:
=>A friend of mine is having recurring corrosion problems with his Volvo
=>Duoprop outdrives. These have stainless steel props and the boat is a
=>Regal Commodore 322. The Volvo and Regal reps can't seem to get it
=>fixed. Anyone else had this problem?
=>
=>__
=>Dennis J. McTigue | Internet Address: McTi...@OSU.EDU
=>College of Dentistry | 305. W. 12th. Ave. Columbus, OH 43210-1241
=>Ohio State University | Phone (614) 292-4250 FAX (614) 292-7619
=>
=>
Does he have the equivalent of a 'Mercathode' system installed? A
"Mercathode" is an active corrosion prevention system. I don't
really know how it works - but it is hooked up to the battery and
provides greater corrosion protection than just zincs. Our marina
owner says "well, if you *must* have a stainless prop (he doesn't
like them), get a mercathode". And this is born out by the amount
of corrosion on outdrives with SS props and no mercathode. Oh -
this is only matters for boats kept in the water. I'm assuming a
322 Regal is kept in the water during the season.
There are at least two types of Mercathodes available: one that
bolts directly into the outdrive (and only works for Merc drives),
and one set that consists of two 2" diameter devices that look
vaguely like small speakers. They are attached to the transom,
near the outdrive. A small controller is installed inside the boat
and wired to the battery. The 'speakers' are also connected to the
controller. The installation is pretty easy, but you do have drill
holes through the transom and properly seal everything. You don't
want to introduce transom rot by doing this incorrectly. You also
must do a good job with the wiring since the voltages and currents
are very low. Any losses due to bad wiring would likely greatly
reduce the effectiveness of the system. Since this boat is a twin
engine boat, I think two sets of mercathodes should be installed.
All twin engine boats that I have seen with Mercathodes have two
sets.
When I bought a set about fives years ago, one set cost about $85
(US).
You may want to check into whether Volve sells something similar.
Of course, the zincs must be properly installed too. Any contact
surfaces between the zinc and the attachment point must be clean
and bright. Don't reuse zincs unless they are still heavy and you
have wire brushed them to a shiny surface (rarely worthwhile except
for the large plate type zincs that cost $50).
Make sure any ground straps between the drive leg and the gimble
are attached. Make sure any ground straps inside the boat are
properly attached.
My Merc Mirage prop came with a large star washer. Apparently,
this is to give a good clean electrical connection between the prop
and the shaft. Could be wrong here, but in my opinion, the washer
was too thin to server any fastening purpose.
Mike
BellSouth News Server
I've had the same problem. There doesn't seem to be a fix and Volvo doesn't
seem too interested beyond recommending switching to a different material
for the 'zincs', magnesium I think, if the boat is in fresh water. Mine
were supposedly done a couple of months back, but I haven't had it out of
the water yet to see if it's doing any better. The Marina says it is
happening on a lot of drives (including some Mercs to a lesser extent) and
believes the finishes arre just not as high quality as they used to be. I
question this answer as the pitting is worse around fittings than it is on
the exposed metal where the paint has worn off.
I've taken pictures periodically when the boat's been out of the water and
plan to approach the issue with the dealer one more time before the warranty
is up.
There have been a couple other mentions of the issue here in the newsgroup,
but not a groundswell of reported problems.
If your friend gets somewhere with Volvo, let us know.
-Ed G.
Dennis J. McTigue <mcti...@osu.edu> wrote in message
news:37BC3D22...@osu.edu...
> A friend of mine is having recurring corrosion problems with his Volvo
> Duoprop outdrives. These have stainless steel props and the boat is a
> Regal Commodore 322. The Volvo and Regal reps can't seem to get it
> fixed. Anyone else had this problem?
>
> __
> Dennis J. McTigue | Internet Address: McTi...@OSU.EDU
> College of Dentistry | 305. W. 12th. Ave. Columbus, OH 43210-1241
john sipkens
a bad wiring system that is feeding current into the water and causing this.
--
John Sipkens
BellSouth News Server <ed_g...@nospam.bellsouth.net> wrote in message
news:JU1v3.3535$El2....@news3.atl...
MuryMann
>current.
9 out of 10 times, this is the culprit. The trick is to increase the "zinc"
surface on your boat and make sure your electrical systen on board isn'tt
adding to your problem. Much written on how to do this in previous threads.
BK
Ed
<j.si...@worldnet.att.net> wrote:
>If this is happening to a lot of drives in your Marina I would look for stray current. Some one has
>a bad wiring system that is feeding current into the water and causing this.
The thought had crossed my mind, well actually, someone here suggested
it when I first noticed the problem. There are two or three docks
between us and the first with shore power (though the dock itself is
wired with 110 for lighting).
Also, I've walked the dock and taken a look at the older boats in the
slips around me, some which haven't moved since I've been there, and
they don't seem to suffer the way our boat does.
-Ed G
M.Holden
"Dennis J. McTigue" wrote:
> A friend of mine is having recurring corrosion problems with his Volvo
> Duoprop outdrives. These have stainless steel props and the boat is a
> Regal Commodore 322. The Volvo and Regal reps can't seem to get it
> fixed. Anyone else had this problem?
>
> __
> Dennis J. McTigue | Internet Address: McTi...@OSU.EDU
> College of Dentistry | 305. W. 12th. Ave. Columbus, OH 43210-1241
> Ohio State University | Phone (614) 292-4250 FAX (614) 292-7619
there are two causes of this type of corrosion; stray current and galvanic
current.
galvanic corrosion is generated by metal in water. 2 different metals
produce
a higher voltage [and, therefore, current], and corrosion can be rapid
unless
protection is provided by either a sacrificial anode [zinc, aluminum, or
magnesium, depending on the application], OR an impressed current
protection
system [Mercathode]. if the impressed current system goes wrong, though,
it will cause stray current corrosion.
stray current corrosion can be caused by a lot of different things, almost
any electric circuit on board that's gone wrong. anodes will not save you
if this is happening.
what your friend needs, is a silver / silver chloride half cell from Yacht
Corrosion
Consultants, Ventura, Calf. [805-644-1886] that you can use with a
voltmeter,
and either their work book, or maybe better, 'The marine electrical and
electronics
bible' by John C. Payne. they both have step by step instructions on
tracking down the
problem[s].
while you wait for delivery of those things, keep the boat disconnected
from shore
power as much as possible.
good luck, Mark Holden
Steve Galante
I don't know if this will help or not, but Volvo-Penta does have their
own version of Mercury's Mercathode. It is described on page 30 of
their Parts catalog. Go to http://www.penta.volvo.se/parts/index.html
Click on the 99 Catalog and click on Electrical system. They show it
and decsribe it on a page marked 30. You will need Acrobat reader,
which you can download from the same page you click on Electrical system
from. Volvo does have a solution. It may be expensive though. I hope
this helps.
Steve Galante
Sent via Deja.com http://www.deja.com/
Share what you know. Learn what you don't.
ZWERLING
drives? Does anyone have any idea approximately what these devices cost?
Thomas Klein
<M.Ho...@flash.A2000.nl> wrote:
>any electric circuit on board that's gone wrong. anodes will not save you
>if this is happening.
>what your friend needs, is a silver / silver chloride half cell from Yacht
>Corrosion
>Consultants, Ventura, Calf. [805-644-1886] that you can use with a
>voltmeter,
>and either their work book, or maybe better, 'The marine electrical and
>electronics
>bible' by John C. Payne. they both have step by step instructions on
>tracking down the
>problem[s].
>while you wait for delivery of those things, keep the boat disconnected
>from shore
>power as much as possible.
>good luck, Mark Holden
Mark -
Any idea on the cost of the half cell. I'm having severe problems on a
Bravo III drive. Actually needed to replace the casing .Already
ordered the bible...... I want to spend my money protecting the drive
and not replacing it.
Tom Klein
tkk...@eclipse.nospam.net (remove nospam)