Zincs Needed In Fresh Water?
 

Hi I was wondering if anyone knows if you need to have zincs on your
prop shaft in fresh water?The one on mine looks original(20+ years)
and still appears 99% intact.
Thanks Dave

Dave Mac wrote:

Hi I was wondering if anyone knows if you need to have zincs on your
prop shaft in fresh water?The one on mine looks original(20+ years)
and still appears 99% intact.
Thanks Dave


Pure "fresh" water does not conduct, and will not foster
elecrolytic corrosion. Therefore, in theory, you do not need zincs.

All water contains some dissolved salts, and those loose ions do
permit corrosion a slow as you like.

Zincs won't hurt, magnesium is better for fresh water, but if they
don't dissapear, don't replace them.

They won't work at all if they have been painted.

Terry K

I have a steel boat in fresh water and I keep all of my zincs on even when
stored on the cradle as per recommendation of my surveyor when I originally
purchase the boat.
Leo
s/v Red Rover
"Dave Mac" wrote in message
om...
Hi I was wondering if anyone knows if you need to have zincs on your
prop shaft in fresh water?The one on mine looks original(20+ years)
and still appears 99% intact.
Thanks Dave

That just means you have a properly bonded and isolated electrical
system on your boat and a properly set up shore power to your
dock...or your mooring.

That also means all the boats nearby are in good electrical order.
Were they not, you would see the zincs going. I replace mine every
four years or so in Lake Ontario. It's a cheap fix, cheaper than
bronze thru-hulls at any rate.

R.

On 27 Nov 2004 06:12:41 -0800, (Dave Mac) wrote:

Hi I was wondering if anyone knows if you need to have zincs on your
prop shaft in fresh water?The one on mine looks original(20+ years)
and still appears 99% intact.
Thanks Dave

Zincs in salt water, magnesium in fresh. Install magnesiums, even if you
currently do not have a problem. Things can change and if they do, you will
be protected.
Steve
"Dave Mac" wrote in message
om...
Hi I was wondering if anyone knows if you need to have zincs on your
prop shaft in fresh water?The one on mine looks original(20+ years)
and still appears 99% intact.
Thanks Dave

Yes, don't replace them if they don't disappear, but *DO* do the following:

- Inspect for signs of corrosion, especially in areas where there may be
junction between two metals or an air gap. Rivets and the connections on
your bonding circuit (grounds) are in particular susceptible ...loose rivets
means corrosion likely exists and bonding circuit connections should remain
clean. They should also be sprayed with something like Corrosion X to keep
them clean and corrosion free.

- Once a year or so, remove the zincs (or magnesiums) and wire-brush them
and the boat where they mate up. It doesn't hurt to use a wire brush them
on the outside too if it looks like crud or paint is preventing good water
contact.

Brian D



"Terry Spragg" wrote in message
...
Dave Mac wrote:

Hi I was wondering if anyone knows if you need to have zincs on your
prop shaft in fresh water?The one on mine looks original(20+ years)
and still appears 99% intact.
Thanks Dave


Pure "fresh" water does not conduct, and will not foster elecrolytic
corrosion. Therefore, in theory, you do not need zincs.

All water contains some dissolved salts, and those loose ions do permit
corrosion a slow as you like.

Zincs won't hurt, magnesium is better for fresh water, but if they don't
dissapear, don't replace them.

They won't work at all if they have been painted.

Terry K

Good point. In addition to my other recommendations, use a zinc saver
(diodic isolator) on your port power to prevent boat and zinc corrosion when
plugged in at a dock somewhere.

Brian D



"rhys" wrote in message
...
That just means you have a properly bonded and isolated electrical
system on your boat and a properly set up shore power to your
dock...or your mooring.

That also means all the boats nearby are in good electrical order.
Were they not, you would see the zincs going. I replace mine every
four years or so in Lake Ontario. It's a cheap fix, cheaper than
bronze thru-hulls at any rate.

R.

On 27 Nov 2004 06:12:41 -0800, (Dave Mac) wrote:

Hi I was wondering if anyone knows if you need to have zincs on your
prop shaft in fresh water?The one on mine looks original(20+ years)
and still appears 99% intact.
Thanks Dave