Antifoul coming off rudder

[Sydneysider]

I had the boat antifouled last September, and at that time had noticed the paint had fallen off the prop strut and the leading edge of the rudder, it was deemed the boat was over anoded, so two small anodes on the rudder were removed, we could not get a prop anode so a shaft anode was used, there is also a transom anode that was retained. I have been in the water (swimming) quite a bit lately and noticed on the weekend the bottom of the rudder on both sides the antifoul paint has just fallen off, about the size of a hand on both sides, and there is also a small bare bit at the top on one side, had a look and feel last week at it seemed to be all there, Prop and shaft have propspeed - any ideas what could be causing this?
Boat is Beneteau Antares 30
Regards Scott

 

[baldyash]

Same boat & I antifouled the rudder last year for the first time after 2 years with none. My presumption was that its stainless & didn't require any!! (wrong) Used Jotun sea Queen on the hull & rudder & am very please with the result, apart from the rudder. No heavy fouling (on the rudder) but after 7 months in & a pressure wash there is very little AF on the rudder left, but the hull is still good. Maybe a primer should have been used?

 

[Sydneysider]

Thanks Baldyash, They stripped it back to bare metal and put a grey primer on the rudder first, then sprayed antifoul, assume as hull. I cannot tell if the primer has let go as well but there quite a lip of 1/16 inch where it has broken free.

 

[omega2]

consider the amount of water the prop is chucking at the rudder and there lies your answer.

 

[chuzzlewit]

consider the amount of water the prop is chucking at the rudder and there lies your answer.

Yes. My Merry Fisher 805 does the same.

 

[itchenseadog]

Almost certainly cased by prop wash

 

[Elza_Skip]

I am anti fouling my rudder and am using a 2 part primer Interprotect. This is much more durable so I am hoping it will stand up to the prop wash

 

[omega2]

Whatever you paint the rudder with it will get washed off, sooner or later, we use Sea Queen bi-annually the hull after power washing looks like we just painted it, but the rudders are almost devoid of anti foul.

 

[Sydneysider]

Thanks for your replies, It just seems a bit strange that a piece of antifoul has just flaked off with a distinct edge and not just worn off, would propspeed on the rudder help?

 

[omega2]

Thanks for your replies, It just seems a bit strange that a piece of antifoul has just flaked off with a distinct edge and not just worn off, would propspeed on the rudder help?

maybe it was not prepped as good as it should have been? no worries though you are not alone!! Our boat is 1986 and the rudders are still whole. LOL

 

[Anders_P42]

Scott,

I read on here, recommended by JFM and others, that TK line works well on props so assume it will handle prop wash?

http://www.force4.co.uk/9073/Force-4-TK-Line-Antifouling-Spray-Clear.html

Anders

 

[Sydneysider]

Hi all,

Had the boat hauled out and made the following discoveries, flaking antifoul off metal parts; Rudder and shaft bracket covered in small bubbles, looking like the paint is about to lift.
Antifoul flaking around the two brass intakes
The transom anode is bright where it is consuming, there is an anode on the shaft that appears to be normal.
The marine electrician suspects stray current from an outside source - Shore power earth wire and has suggested the fitting of a galvanic isolator?
I have read a bit about it and it seems the anodes should be consumed before an attack on the other harder metals?
Would appreciate your opinions