what do you think? aluminum better than zinc?
- Thread starter Tricia
- Start date
kinda depends on if the boat has any aluminum underwater now don't it. For Fiberglass boats with SS shafts and bronze props it would work fine. However, consider that most are connected to shore power by a ground and other boats are connected to that same ground also. You would be forcing your system to use other folks zincs as zinc has a more base voltage than aluminum.
Course if you isolate ALL you underwater metal this is not even an issue is it?
Course if you isolate ALL you underwater metal this is not even an issue is it?
Bill --
Assume correct AC wiring is in place - including safety green bounded to the shaft on your boat - and assuming A/C cord is connected to shore power.
As you say zinc is less noble than aluminum. So if the neighbor boat is protected with zinc then won't his zincs protect your boat - including your aluminum anodes? Hence his anodes errode away whereas yours do not - and neither do your other underwater metals.
Neat - means your "aluminums" should last a very long time.
Assume correct AC wiring is in place - including safety green bounded to the shaft on your boat - and assuming A/C cord is connected to shore power.
As you say zinc is less noble than aluminum. So if the neighbor boat is protected with zinc then won't his zincs protect your boat - including your aluminum anodes? Hence his anodes errode away whereas yours do not - and neither do your other underwater metals.
Neat - means your "aluminums" should last a very long time.
I think I have read that aluminim is more suitable for fresh and brackish water, with Zinc being more appropriate for salt and brackish water. I have read that you should disconnect your shore power cable when not using it, since the ground does have a small potential difference which can act to accelerate galvanic corrosion.
I'm re-packing the stuffing box on a bronze rudder post. (Required removal of steering gear for other reasons) The steering quadrant came off fine only a few stiff bolts with very little corrosion. The boat is a 1979 Leigh 30 - all original steering gear and the quadrant is aluminum - in perfect shape. Bronze and aluminum? I don't get it, no corrosion. On the bronze heel fitting for the rudder there is no zinc of any kind.
Can someone explain why there is not a problem here? I don't want to add zinc protection and invite problems. (Prop and stainless shaft are properly protected)
Can someone explain why there is not a problem here? I don't want to add zinc protection and invite problems. (Prop and stainless shaft are properly protected)
if im reading this correctly, the answer is no. the neighbors zinc wont protect the boat next to it that is using the more noble aluminum as an anode because they are not grounded together. and if aluminum was an acceptable anode for boats, there would be a choice on which kind to buy at the marine store....
The neighbors boat would protect your boat, assuming neither boat has a galvanic isolator (which you should)
AL is available in some chandleries, but its rare since many boats are powered with aluminum outdrives or outboard engines, which would still need a zinc to protect them, and why stock 2 parts when one will work for either.
AL is available in some chandleries, but its rare since many boats are powered with aluminum outdrives or outboard engines, which would still need a zinc to protect them, and why stock 2 parts when one will work for either.
i have been under the assumption that zinc is for salt water and magnesium is for fresh water is that not correct .........
regards
woody