Installing zinc ?

[RussT]

I did a search, and know I need enough, but not to much zinc on my boat, still not real sure how to tell when enough is enough tho. I have a chunk of zinc, but have a few questions on how to mount it. Does the zinc need to be in contact with the aluminum hull, or does it need to be "insulated" from the hull? Do I just drill thru the transom, and bolt it on? Last year, my boat spent a week in the Alsea below tidewater, the zincs that are on it, got eaten up some. The end of this month, I'm spending a week at Astoria,and am concerned about corrosion. Any information would be appreciated.
RussT

[Catching Nemo]

1. Don't think you can put too much zinc on.

2. Needs to have contact with the hull.

3. Instead of drilling holes, weld it on.

4. There are freshwater and saltwater zincs with different alloy mixes.

5. Freshwater zincs will get eaten up really quick in salt.

[RussT]

Thanks for the info. the piece of zinc I have weighs 10+ pounds. there is no provision for welding it on, either welding a bracket to the transom and then bolting it to that or bolting directly to the transom are my only options.
Don't know the composition of the zinc alloy, I bought it thru boatzinc . com. There are zinc's on the trim Cylinders, and on the cavitation plate of the outdrive on my boat, but I think I need more (peace of mind thing)
RussT

[apparentgenius]

RussT,

Check out this report for corrosion prevention. http://www.kastenmarine.com/corrosion.htm There is also a link to the metal boat quarterly that has a good article. I don't know how big your boat is, but 10 pounds may be way too big. I have a 25ft aluminum boat and have a couple on each outboard and one fastened to a transducer bracket, maybe 2 lbs. And yes, you can have too much zinc. IF it is too big, it won't work properly and can cause a basic solution around your boat that will do more damage than salt.

glen