Prop shaft anode

[AllanG]

Thanks for all the comments, and it's very interesting to see there are two very differing opinions, which makes my decision more difficult.

Allan

 

[DAKA]

I am somewhet suprised by Latestarters and Daka's comments above.

I had a problem with a pair of new props ( nickel, aluminium, bronze, (Nibral)) from a well known uk Manufactuer and shafts from the same manufacturer aqualloy 80.

According to the above posters I dont need any shaft anode or electro eliminator?

I put down the problem I had to poor connectivityaccross the R&D coupling, green connections on the shaft brushes or green wire ends ( not tinned at the time) and or no shaft anode.

After that fiasco I put new props from the same manufacturer with the same shafts, re wired electro eliminators replaced, an electrical bridge accross the R&D and shaft anodes and hey presto no further problems on that or further boats with the same set up?

Unfortunately I havent time to conduct a metallurgist report , wish I had as I am intrigued as to establishing exactly what has been supplied.

If you post details of the actual metals (trade names confuse the issue) VicS hopefully will pick up on it being the forum wizard on electrical differences / tolerances allowing for low oxygen water etc

Vetus being a well known supplier supply both good , not needing anodes and cheap which require anodes, a mixture of the two will also require anodes.

Did you keep the knackered ones ?

If a boat has a serious electrical issue anodes will waste away in a month and wouldnt do a lot of good over a year anyway.

 

[Latestarter1]

Unfortunately I havent time to conduct a metallurgist report , wish I had as I am intrigued as to establishing exactly what has been supplied.

If you post details of the actual metals (trade names confuse the issue) VicS hopefully will pick up on it being the forum wizard on electrical differences / tolerances allowing for low oxygen water etc

Vetus being a well known supplier supply both good , not needing anodes and cheap which require anodes, a mixture of the two will also require anodes.

Did you keep the knackered ones ?

If a boat has a serious electrical issue anodes will waste away in a month and wouldnt do a lot of good over a year anyway.

I am totally with you on this one and it appears to be typical of addressing the issue and not the cause. Vessel in question has serious galvanic issues...However.

Problem is exactly as you put it all Nibrals are not equal, you will note I mentioned class 1 Nibral as reference to the now extinct BS1400 AB2 and Naval specification DEF STAN 02-747. The mention of a specific manufacturer and recommendation of shaft anodes rung alarm bells, and at this point time to butt out before thread is deleted.

 

[Bandit]

My props were manufactured to BS 1400 nickel aluminium bronze.

I did what i said above plus having the boat electrically checked in the water on its berth plus having a galvanic isolator fitted.

I stick by electro eliminators and shaft anodes and they work.

Most modern boats in marinas are permanently on shore power, its not nescesarily your boat at fault it could be the port installation, pontoons or electrics or your neighbouring boat or it could be your boat developing a new fault, but either way if the first you know about it is heavily corroded set of props with a 10 week delivery on a new set you are stuffed.