Hey Jon- I'm embarrassed to say that the CW magazine was on the bedside stack with 500 others waiting to share a 3 minute daily time allotment!

I have seen the same performance table over and over in different articles online. It seemed to originate with the article by Wigg and Fleury "What's the Truth about Aluminum Sacrificial Anodes?". No one quotes the source. Perhaps the Navy??

Here are a couple of my spent prop anodes. I started asking questions when the second spent "zinc" in a row looked like it had been shot out of a volcano. I had never seen a "zinc" behave this way so began looking for causes like that steel boat next to me.

Oh, wrong assumption. It was an aluminum "zinc"! (The diver didn't tell me he switched to aluminum.)

The aluminum anode was doing its job and presenting a lot of surface area to work.