Zinc cathodic protection calculations for aluminum hull in salt water

[ayoung802]

I think the title pretty much says it all. I'm a mechanical engineer working in the marine industry so I have a basic understanding of corrosion and cathodic protection, but that is it. I'm trying to find information or a lead on how to calculate the number/size/amount of zincs I need to protect an aluminum hull in sea water?

I've spent time researching this topic and all I can find is how to test the hull once it is in the water and what ranges are good. We will run those tests once in the water, but it takes time and there are other factors that concern the credibility of the results until after the boat leaves the shipyard. In the past we've built FRP and Steel hulls so having too much isn't as great of a concern. From my research I have found that for aluminum hulls it is possible to have too much so it is worth spending the time upfront.

Thanks in advance

 

[berkshire]

ayoung802
Check out the article: protecting Aluminum appendages
On page 22 of the February/March edition of Professional Boat Builder. by David Rifkin.

http://www.proboat.com

B.E.

 

[ayoung802]

I just got that magainze yesterday, what do you know. I read the article and it defiently furthered my knowledge of the topic, but I'm looking for equations or rules of thumb on how big and how many zincs are needed.