Nomad Willy
Guru
"So far I've read from 1/4" to 1" which is quite a big difference."
I'm think'in much closer to 1". That's about exactly what Willy's got.
I'm think'in much closer to 1". That's about exactly what Willy's got.
I'm think'in much closer to 1". That's about exactly what Willy's got.
I walked through a boat yard a couple of years ago with my multimeter and checked the continuity of anodes on about 40 boats. Only two boats had any continuity at all.
Photo below shows a not bad looking anode showing O.L. (open line = no continuity) with the shaft.
Photo also shows a cheap consumer grade meter set on megohms. That meter has a resolution of 1K ohms in the lower megohm range and 10K at its higher range.
It is not being used properly and is worthless for that application in any event.
That being said, you are correct that continuity between the zinc and the protected material is important. A zinc (especially a cheap Chinese zinc that may contain iron contamination) will develop an insulating oxide layer that essentially stops it from working.
Murray do you have a shaft seal that has water taken off the seawater elbow feed? If so 1/4" would probably be enough but I'm not sure. I would think 5/8" would be plenty for a water fed stern tube and probably for a static one too but I think it's a little questionable. Probably fine .. just don't want to put a personal blessing on it. Lets see what others think.
Eric - There is a 'grease groove' machined in the outside of the outer race with a hole to allow grease into the inner bearing.Anode,
In post #39 How does the grease get into the inner brng and how is the shaft attached to the inner race?