Re: [AlbinVega] galvanic corrosion from other boats chargers & stray currents (discussion)

[WL]

Hi Stephen:
I did have a big problem some time ago: I started the engine, tried to
get into reverse (to get out
of the slip), and guess what? A lot of commotion astern, but the boat
didn't move. After
inspection I found that the sleeve was completely gone- eaten up by
galvanic action.
I checked all the boat near my boat, and found that a boat next to me
was using one of
these "cheap" chargers, as a matter of fact, they were using an
inexpensive trickle charger
which I consider being the worst.
Upon my alert other skippers also found major galvanic action on their
boats. Needless to
say- these "cheap" chargers are no off limits.
And to answer Hielke's question about the motor, gear box, shaft... of
course, all these
parts are grounded! (unless the boat sits high and dry ashore).
And about never having seen a boat sink because of galvanic action- I've
seen a boat loose
the rudder- besides me loosing the sleeve (for the reversing gear).
Wilhelm V-257

Stephen Birch wrote:

 

[jvancraaikamp]

Hi Wilhelm

It might be an idea for you to protect your boat with a sinck annode.
If a metal desintegrates it is caused by a DC current. The DC
current will provide the neccessary ions to free the Fe molecules.
With galvanic corrosion there is an order of desintegration of
various metals. School has been a while ago but I know that lead and
sinck are somewhere low on that list. What I don't understand is why
the DC current would flow from the shore, from your neighbour to
you and from your boat back ashore. If there is no loop there is no
cuurent. If your boat falls apart your boat must be the possitive
pole in the water so your ground is above zero volts. So what you
are suggesting is that your neighbour charges the water to be a
negative pole. I'm interested how he does that.
P.S. In holland we have a protection on the AC powersupply that
compares the current going through both conductors so if there is
any current leaking to earth it cuts off the fuse (called earthleak
protector).
Regards Jan van Craaikamp V973 Holland.

 

[stevebirch2002]

HI

Oops. Not had a problem like that! Sounds a major problem. The only time I
have
seen anything like that was when one of the keel drain plugs was changed
for an
ordinary brass one. After about two months the Vega started to sink on her
pontoon. Qucik action saved her from sinking totally.

Was your sleeve the original one? We seem to chnage them in the UK about every
five to ten years, depending on the abrsiveness of the water.Kind Regards

Steve Birch
At 08:51 16/12/02 -0500, you wrote:

 

[wxt8981]

Hi Jan
thanks for telling me.. but be assured- I do have a big (and it is big)
as you call it
'sinck annode' fastened to the hull- + another one (not big, but round)
on the shaft
next to the propellor
I've learned my lesson when I lost the sleeve...))
Wilhelm V-257

jvancraaikamp wrote: