A somewhat pink prop !

[superheat6k]

Looks like I will be buying a new Starboard prop this Winter.

All due to a corroded, but only 2 year old shaft brush with an 80 ohm resistance between the carbon face touching the shaft and the brush holder itself.

0 ohms between the rudder and the zinc, hence the lovely brass colour.

Heyho !

 

[Concerto]

It certainly looks pretty in pink!

 

[Plum]

Looks like I will be buying a new Starboard prop this Winter.

All due to a corroded, but only 2 year old shaft brush with an 80 ohm resistance between the carbon face touching the shaft and the brush holder itself.

0 ohms between the rudder and the zinc, hence the lovely brass colour.

Heyho !

Is that nose-cone a zinc anode?

Www.solocoastalsailing.co.uk

 

[oldgit]

Is that nose-cone a zinc anode?

Www.solocoastalsailing.co.uk

been there.

Couple of big pairs of S/H props of ebay.
Might be worth a look , with bit of tweaking from your local propshop might save a bit ?

 

[VicS]

Looks like I will be buying a new Starboard prop this Winter.

All due to a corroded, but only 2 year old shaft brush with an 80 ohm resistance between the carbon face touching the shaft and the brush holder itself.

0 ohms between the rudder and the zinc, hence the lovely brass colour.

Heyho !

Vyv always says that a zinc anode wii not prevent dezincification,

If he is correct you will need to consider the possibility that there is some reason, other than the corroded shaft brush, for the condition of your prop

 

[vyv_cox]

Vyv always says that a zinc anode wii not prevent dezincification,

If he is correct you will need to consider the possibility that there is some reason, other than the corroded shaft brush, for the condition of your prop

Yes, the zinc phase in brass or manganese bronze contains a very small proportion of copper, so the voltage between it and a zinc anode will be very small indeed. Very limited protection is provided. My anode-bonded P-bracket dezincified quite badly. I dumped the anode and painted the replacement P-bracket.

 

[Momac]

Looks like I will be buying a new Starboard prop this Winter.

Outdrives might perhaps less trouble?

Is there a concern the propeller may be structurally unsound ?

 

[superheat6k]

Outdrives might perhaps less trouble

Is there a concern the propeller may be structurally unsound ?

I would love to have out drives, but unfortunately I can't until the hole in my bottom heals over, you see this was a solemn promise to myself many many moons ago !

The port prop is fine and the high resistance across the shaft brush was definitive. The bonding to the P Bracket and rudder is fine, so I ma satisfied the problem is located.

I am fitting PSS seals to replace the stuffing boxes, so hopefully a drier environment around the brushes in future. I have noticed there are also bonding cables across the plastic R&D shaft couplings so it looks like these have also failed. The couplings reside in something of a black hole, and it is only now I have properly examined them ready for dismantling and removing the couplings so I can pull the shafts out.

I will have a look at Ebay for the prop listings, thanks.

 

[Heckler]

Looks like I will be buying a new Starboard prop this Winter.

All due to a corroded, but only 2 year old shaft brush with an 80 ohm resistance between the carbon face touching the shaft and the brush holder itself.

0 ohms between the rudder and the zinc, hence the lovely brass colour.

Heyho !

Before lashing out I would get a file and file a small portion in a sage place, I would bet that that dezincification isnt as deep as you think it is!
I had a thru hull that looked that bad, after I changed it I hacksawed it through, the pink bit was only skin deep!
,

 

[Plum]

Yes, the zinc phase in brass or manganese bronze contains a very small proportion of copper, so the voltage between it and a zinc anode will be very small indeed. Very limited protection is provided. My anode-bonded P-bracket dezincified quite badly. I dumped the anode and painted the replacement P-bracket.

Interesting. So are you saying protecting brass/manganese bronze props with a zinc anode is not necessary?

Www.solocoastalsailing.co.uk

 

[Momac]

My props are starting to look a bit pink too.....l

 

[LONG_KEELER]

My props are starting to look a bit pink too.....l

Is that the first openly gay propeller on this forum ?

 

[superheat6k]

Before lashing out I would get a file and file a small portion in a sage place, I would bet that that dezincification isnt as deep as you think it is!
I had a thru hull that looked that bad, after I changed it I hacksawed it through, the pink bit was only skin deep!
,

Once it is off I shall treat it to a hard steel wire brush on the angle grinder and will soon see if it is only skin deep. I reckon if it does need changing to maintain balance I will have to replace both Port and Stbd.

 

[Hot Property]

Sorry to hear of your prop woes Trevor. Worth considering an outboard boat next time? Look to the right and you will see what my prop looks like next time you walk down your pontoon......

 

[vyv_cox]

Interesting. So are you saying protecting brass/manganese bronze props with a zinc anode is not necessary?

Www.solocoastalsailing.co.uk

If the only protection provided was to a fixed manganese prop that is probably the case. But the anode, either shaft or hull via a brush connection, is also protecting the prop-to-shaft galvanic couple and the washers/nut/split pin holding the prop onto the shaft. In the case of a folding or feathering prop there can be quite a variety of different materials involved that form their own galvanic couples.

This is a photo of the nut from my prop shaft when I had a fixed prop. There had always been a shaft anode. The nut is severely dezincified.

 

[superheat6k]

Sorry to hear of your prop woes Trevor. Worth considering an outboard boat next time? Look to the right and you will see what my prop looks like next time you walk down your pontoon......

View attachment 81583

Yes - but I would need quite a hydraulic ram to lift my props clear of the water !