shaft anodes required ?

[BartW]

Blue Angel never had shaft anodes,
she has big anodes on the prop nuts,
2 big anodes on the transom,
and a number of anodes on the trim flaps,

on the shafts nor the props are any traces of corrosion,
can we conclude that we don't need shaft anodes ?

I've seen many similar boats with anodes fixed around the shafts,
these anodes create some unwanted drag, why or how do they decide todo that ?

 

[kashurst]

if the prop nut anodes last long enough then no you do not need shaft anodes.

I have prop nut anodes but they are too small and don't last long enough, So now I have shaft anodes instead that last @ 2 years along with the main hull anode.

 

[Bandit]

Check with a multi metre if the shafts, props, p-brackets and rudders are connected to the hull anodes.
Do you have shaft brushes or continuity across the shaft coupling?

 

[Portofino]

My shafts are metallically connected to the G box , likewise to the engine and that’s connected to the hull anodes on the stern by a massive earthing looking straps ( think church lightening conductor) So no need for anything else .

Props have 60 mm prop anodes like yours over the bolt - streamlined.

No sign of any corrosion.
Prop anodes last a season . Hull anodes very well , could stretch to two seasons but I don’t - all replaced annually.

Beauty of this system you are not farting about with out of sight cooler anodes on the engines or pratting about stressing out with ad hoc freshwater rincing with a Heath Robinson DIY set up in some vain attempt to prevent your coolers rotting out prematurely.

Relax with a beer ?

 

[omega2]

bridge the r&d coupling, and if your anodes are working no need for anything else.

 

[BartW]

My shafts are metallically connected to the G box , likewise to the engine and that’s connected to the hull anodes on the stern by a massive earthing looking straps ( think church lightening conductor) So no need for anything else .

Props have 60 mm prop anodes like yours over the bolt - streamlined.

Relax with a beer ?

PF, I think most Italian builders use the same methods

santé :very_drunk:

 

[MapisM]

My shafts are metallically connected to the G box

Why, have you ever seen any which aren't?

 

[Portofino]

Why, have you ever seen any which aren't?

Yes !
You can get anti vibration couplings whereby electrical continuity of both sides could be interrupted by a layer of elastomer ..

http://www.directindustry.com/industrial-manufacturer/anti-vibration-coupling-226224.html

Shaft brushes are available to restore continuity from the inside which may connect to an anode or go down the external bolt on route and carry the inherent risks of them spinning off as the zinc depletes and the thing loosens sliding about .

 

[QBhoy]

As some have said. Easy way to answer is to check continuity with a meter...

 

[MapisM]

Yes !
You can get anti vibration couplings whereby electrical continuity of both sides could be interrupted by a layer of elastomer

I'm aware that such things exists, but what I asked is if you've ever seen any.
Me, I can't remember to have ever come across such coupling, at least in high(ish) power boat.
I can only think of a 10m "gozzo" (a typical IT displacement boat derived from fishing boats) with such shaft dampener, but that was attached to a 60hp engine (or thereabout, can't remember exactly) on a 7kts boat, if you see what I mean...
Mind, for all I know there could be flexible couplings also on shafts of much larger boats - I'm just unaware of any.
Is there any asylum boat with such setup?