Corrosion on Propellor

I just pulled my 325 out of the water after 7 months of use from brand new and was shocked to see the condition of the propellor, attached are the pics that I find unbelievable

Hi Xantos

I have just seen your Facebook photo. The condition of your propeller is shocking, especially after such a short period, and something is quite clearly wrong. It looks quite beyond repair, certainly the blades are destroyed. From the looks of it the prop is a two blade  Flexofold? There is no way in normal conditions that it should be in that condition. I have tried to look at your sail drive leg anode and, although it is not very clear in your photo, it does appear to be quite corroded although nothing like as bad as your prop.

 I suggest that there could be a bad earth bonding problem possibly causing the problem. May I suggest that you check the continuity of the bonding right through the hull, maybe by engaging a specialist engineer to help. It is also possible that where you berth could be causing part of the problem. Is there steel marina pontoon stanchions nearby, or indeed other steel structures which could be having a bad effect, including a poorly earthed steel hulled vessel? Normal shore power connection should not cause this sort of problem unless there is something else wrong.

 I had a two blade Flexofold prop fitted at the time of commissioning of my Hanse 320 and after one season it was still in immaculate condition with hardly any marking. You can see a photo of it in the  'For Sale' items section of MyHanse. It only needed a light wire brushing to get it to the state you see it in. Please don't think I'm trying to push it on to you, I only mention it so that you can see that a propellor of this type should still be in very good condition after a seasons service.

 I hope that you can get a solution to this soon. What is the condition of your other hull anode?

Regards,

John

Edited by JohnA - 06 June 2012 at 16:11

Hi Xantos,

 This is really bad news for you. I would be very concerned if my Hanse agent made that comment to me and I would be requesting him to check the boat out very quickly.

 You say that the other hull anode has gone completely and this makes me really convinced that you have a serious earth bonding failure. May I suggest that you investigate your engine compartment to check that there is no evidence of corrosion to your engine, gearbox and/or sail drive components. Also check your batteries. Do you switch the battery master switches off when you are not on the boat? There should be no evidence of corrosion at the batteries on a boat of that age if nothing else is wrong. If your distributor (agent) won't give immediate help to you, you really do need to engage a marine electrical expert immediately before other damage is done. I would also kick up an awful fuss with Hanse if your agent (who I assume sold the boat to you) will not help you! I suspect that something may have gone wrong at the commissioning stage.

 I suggest that, as the sail drive anode is not badly corroded that it is the prop which is taking all the corrosion in that area, this may suggest that the problem may be the bonding of the sail drive?

 Good luck with solving this problem. I have looked at your yacht on your Facebook pages and she looks really beautiful.

 It is a real regret that many Hanse owners throughout the world seem to have complaints about their distributors. In the UK we are lucky to have a good one who takes their responsibilities seriously and will always help with advice no matter how long after the original sale.

Regards,

John



Edited by JohnA - 06 June 2012 at 17:08

Normaly with a 325 you have a Volvo engine (D1-20 or D1-30).

Hi Xantos

I had a similar problem last year, see my previous post with a picture of the hole in my prop. This is definitely an electrical problem. Your prop, being alloy is acting as your saildrive anode, and be happy that the saildrive did not go down the same road as your prop, because it is also alloy and would cost many thousands to fix.

Several things to consider. Firstly you must use a non copper content antifouling on your prop. For example Trilux33.

Secondly, as previously mentioned, the saildrive must be electrically separated from the engine, if the control cables make contact with both engine and saildrive then you must insulate them some how.

Thirdly is the saidrive anode making good contact to the saildrve housing.

Fourthly if a steal boat is within 20 metres you will act as his anode.

Fifthly if the marina has a poor set up with there electrical supply you need to decouple your boat from the marina supply.

Since I use a 50 watt solar panel, and do not need the use of the marina power, where a steal boat is moored 20 meters from mine, I have less electrolysis

 

Hope this helps Andrew