Shaft anodes

[mlthomas]

Is there an optimum point to put shaft anodes? there is about 20" of shaft before the P bracket if that helps

 

[Bandit]

I dont know about optimum but leave a good gap before the p bracket cutlass bearing or you can starve it of water and it will overheat and destroy the bearing.

I have had shaft anodes drop back and damage the cutlass bearings and ride up and damage the hull.

Now i fit them with a stainless jubilee clip above and below the anode to stop it moving up or down just make sure that when the prop is running forward that the tail of the jubilee is trailing and not snagging any pasing rope or net. This system has not failed yet.

 

[Medskipper]

Shaft anodes should be fitted just 2-3" away from the bracket, the reason for this is to stop any vibration that can be caused by fitting them in a more central position.

Barry

 

[Hurricane]

I've always wondered about shaft anodes.

WHY

Dont boats that fit them have a proper electrical protection system. I cant see how it works - surely shaft anodes will reduce the effectiveness of the main anodes on the rest of the boat.

Perhaps someone can enlighten me.

 

[NorthUp]

They will work alongside the hull anodes and supplement them.
I had to fit both shaft anodes and shaft brushes to a 12m Sealord when the builders had omitted to protect any underwater part except the P brackets, (and that was wired with 1mm wire!- after a year the propellers were nearly falling off, beyond repair, and the shaft nuts were missing)
With the present setup, both shaft and hull anodes erode at a similar rate with regard to their respective sizes, and the 3 year old props are like new.
Incidentally, the boat had twin 6 cyl. Yanmars, but the electrics were not insulated return, the anodes were and are connected to the neg busbar.

 

[Divemaster1]

The stuff works irrespective and working through the mtals ... less precious first then nex tone ... main idea is to protect the more percious metals irrespecteve (rudders props, shafts etc).

Btw ...,looked at the main anodes of the Fjord 40's at the boatshow on Friday ...lots of activity and will give them two weeks at most .... based upon the bubbeling activities observed ...

 

[ADLS]

This spring I had shaft anodes fitted to both shafts for the first time. While returning the boat from UK to Holland in August I noticed some vibration at low revs and while mooring. The boat was lifted out for winter storage in my absence and the boat yard sent me photos via an e-mail showing plastic bags or old plastic boat cover material wrapped around both props. I've told them to leave the material on and I'll investigate it next spring.
I've only ever had fishing line wrapped around the props before and they never caused a vibration problem, so I don't think it would cause drive line wear.

My thinking at the moment is that the anodes have made the prop/shaft debri catch and snarl problem worse and will have second thoughts on fitting them again.

I have a pair of mushrooms fitted on the rudder plus a pair fitted to the steel wing keel and all the fixing bolts for under hull attachments are earth connected as a ring main. This circuit has been checked and proved OK while the boat was out of the water.

While I havn't inspected my shaft anodes yet I will looking at the fixing method and the wasting away effect shape to see if this caused the problem. As for using a SS jubilee clip, I think thats just asking for debri problems.

 

[stefan_r]

[ QUOTE ]
I have had shaft anodes drop back and damage the cutlass bearings and ride up and damage the hull.


[/ QUOTE ]

I second this.

You may find that you can fit them to the nut that holds the props on...if you have a thread going into this not you can get cone shaped anodes that don't upset water flow and the like

 

[mlthomas]

thanks, going to put them on with some sort of screw locking goop so the bolts wont ever come loose and ride down.

Mark