Think I need new props

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SC500

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Have a Princess 430 with twin Volvo TAMD 63P, lifted this week and preparing the props for a coat of Lanolin. When removed props were showing some pink discolouration and the surfaces are heavily pitted.
At the moment I don't feel confident going back in the water with these. Am based in Essex, does anyone know if props with heavy corrosion can be refurbished especially when showing pink discolouration? Also where would the best place to buy replacement props.
All info appreciated, thanks in advance.
 
From another site:"If the prop surface appears uniformly pink, dezincification is at work and essentially your bronze propeller is turning into a useless piece of soft copper. The prop should be replaced, as its structural integrity is questionable. The source of the electrolytic action should be located and stemmed."

As to replacements, it might be worth calling Coastal rides to see if they have the right size lurking on a shelf:
http://coastalrides.co.uk/4-bladed-bronze-shaft-propellers

If not, call Clements Marine:
http://www.clementsmarine.co.uk/contact-us/
 
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Its difficult to say exactly without good pictures, perhaps you should post some?

It sounds like you have straight electrolytic corrosion of a mains earth leak or perhaps a boat nearby has a problem or the pontoon?

What condition are your anodes in? more than 50% gone by weight, shaft anodes missing? shaft brushes?

Do you have a galvanic isolator on your 240v mains supply?

The first thing you see is generally the prop nut starts to show a pinking first, then the blades of the prop start going pink in colour

The next stage is pink and green scabs and pits

The next is severe wastage of thin parts of blades and holes

If you hit the prop with a spanner does it make a clear ring or a bull dang type noise.

In my view assuming you have substantial corrosion, asses the condition of the anodes, firstly you need to find out why you have a problem and cure that for the future, do a continuity test between anodes and all parts of shafts, p brackets, rudders and then all skin fittings to find out what is connected to what or you will fxxk up the next set as well.

You need to inspect carefully all of your skin fittings, valves and the bonding inside the boat for corroded or missing connections, any poor or damaged bonding wiring that has got wet replace wire with tinned wire as it is much more resistant to salt water corrosion.

Also get a good low voltage electrician to test your boat in the water on your berth so see if there is a problem from a nearby boat or pontoon.

Get the prop diameter and pitch off the boss of each prop and any other markings and give Clements a ring and order a new set.

You should be able to use the old ones until the new ones arrive and then keep the old ones as emergency spares.

But you must sort out why you have a problem and cure it.
 
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Thanks for your comments, especially to Bandit. This will send me in the right direction to resolve the issue.
I bought the boat 16 months ago, newly anti fouled with new anode fitted to bow thruster, twin anodes to hull a anodes to each trim tab, no anodes were fitted to the shafts. She is kept in brackish water and anodes are 16 months old. When speaking to other owners and marina staff when initially berthing I was advised that anodes deteriorate about 30% over a year, so decided to leave her in for a slightly extended period to get back onto an annual Maintainance schedule.
When lifted all anodes except the trim tabs were non existent with deterioration to the RH prop. LH prop appears in good condition now I have cleaned it. Prior to cleaning I had assumed both had gone. The RH prop is nearest the other vessel when berthed, therefore would be first inline other than the anodes.
Other boats in the marina within close proximity don't seem to have had this problem. However soon after taking berth a 60 foot older motorboat I think with a steel hull berthed adjacent to us on the same pontoon within 2 metres. The owners live aboard and the she does not appear well maintained, I don't believe it's been lifted for 3-4 years, so may very likely have no anodes of its own, if that matters. I will certainly check whether we have a galvanic isolator fitted and if not will get one. All immediately visible wiring to anodes look good. At the moment I suspect it maybe the adjacent vessel causing this issue and will ask the marina staff to check for low voltage leakage in my location and to check my boat if necessary.
Looks like I'm on another learning curve.
Thanks for this information and contacts, if I can get a new prop for £250, I will be happy.
 
A new prop for £250?? get me a dozen while your at it!! The anodes appear to be working as they have "gone", but have you,got a bridge across the gearbox coupling to the shaft?? Where are you berthed??
 
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You need to be systematic to prove the system you have is robust as I detailed above.

Anodes work by surface area so once an anode is approaching 50% you are loosing the protection, they should be replaced at this point (before 50%), not when they are "gone" that means they are providing a reducing amount of protection so you have had unprotected stern gear for some months.

In salt water a similar sized boat I replace my anodes at least every 12 months, If I was you I would lift in 6 months and pressure wash and asses anode deterioration at that point as well.
 
Bandit said:
You need to be systematic to prove the system you have is robust as I detailed above.

Anodes work by surface area so once an anode is approaching 50% you are loosing the protection, they should be replaced at this point (before 50%), not when they are "gone" that means they are providing a reducing amount of protection so you have had unprotected stern gear for some months.

In salt water a similar sized boat I replace my anodes at least every 12 months, If I was you I would lift in 6 months and pressure wash and asses anode




deterioration at that point as well.
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my monies on no bonding between gearbox and shaft coupling
 
omega2 said:
my monies on no bonding between gearbox and shaft coupling
Click to expand...


+1
Check the earth connection on the shaft brushes just to the rear of the gearbox.
Also, get professional advice from someone like 'Steel developments' Prop repair specialist. He can advise on all props.

As 'FP' said
your bronze propeller is turning into a useless piece of soft copper and integrity will be in question.
Click to expand...

good luck.

RR
 
SC500 has a serious problem it is wise to check everything in a systematic way.

OP needs to be sure he does not screw up the new prop or props in the same way.

You cant refurbish bronze props with electrolytic corrosion. The blades have lost some of the zinc and are weakened.

I would go to Clements as well respected manufacturers and repairers of bronze props. Clements manufacture for most of the UK boat builders and many others.

We have bought many sets of props from Clements and have had many props repaired and some declared beyond economical repair by Clements, I have also used them for my own boat, I have always found them to be reliable and reasonable.

I have no connection with Clements apart from being a well satisfied trade customer.
 
On this subject I'm amazed how many marine companies I see just "fit" new anodes irrespective of the lack of wear and just walk away. I have yet to see a company place the multi meter on the underwater gear either prior or after fitting new anodes on a shaft drive boat.

Just because anodes are fitted and in good condition there not guaranteed to protect everything that's metal underneath.
A simple test of propshaft to anode, rudder to anodes, shaft to anode and in the engine bay, engine to stern gland etc test is vital and you must do this at every opportunity when the boats out the water. This is something you don't get when you employ a marine clean type company, it's assumed because it's wasted its working.
Only this last week I serviced a sterndrive S41 , the transom anode was a bit on the light side, turned out it was magnesium!! Only fitted to one drive the rest were zinc and had wasted at the correct rate for 12 months use.

I asked owner and it turned out he had a mid season lift at cowes sea lift last year and of course had no idea what had been fitted, again an assumption that the said co knew what they were doing.
 
Bandit said:
SC500 has a serious problem it is wise to check everything in a systematic way.

OP needs to be sure he does not screw up the new prop or props in the same way.

You cant refurbish bronze props with electrolytic corrosion. The blades have lost some of the zinc and are weakened.

I would go to Clements as well respected manufacturers and repairers of bronze props. Clements manufacture for most of the UK boat builders and many others.

We have bought many sets of props from Clements and have had many props repaired and some declared beyond economical repair by Clements, I have also used them for my own boat, I have always found them to be reliable and reasonable.

I have no connection with Clements apart from being a well satisfied trade customer.
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The p430 has a shaft brush fitted to each shaft which is wire bonded to the anode bolts, I'd be having the whole lot checked out while its out the water, and after the repairs not re launching until the resistance is an acceptable level.

On the newer princess boats the bonding system is very good, there is no daisy chaining from engines, shafts and shaft logs, each underwater fitting has its own wire right back to the anode bolts ensuring nothing can fail. A great idea in my view. I've seen so many boats with the bonding strip through the hull that have failed wiring, especially the Italian models.
 
I agree with Volvo Paul.

you have a nice boat, good engines look after them.

Get to the bottom of the problem don't do a short cut and assume you have a solution.
 
As already set out, apart from an unwelcome prop investment, this as a two-part challenge, (a) sort anodes (b) sort shore-power connection. Both essential. On the latter, my understanding is an isolation transformer is the most robust solution. The boat's anode continuity may well be fine, doing their job wasting away (and then some) but due to **** electrics elsewhere and beyond the OP's control, wastage rate could be due to inheriting earth leakage by linking up to all the other boats via a pontoon supply with a common earth connection. Getting rid if that (in a safe way) gets rid of the risk, now you can plug in anywhere!
 
Thanks to all. Based in Ipswich haven mariner. Having her checked today and will ensure all points mentioned are covered. Will post findings as soon as available. In meantime I'm trying to find out if I can buy a single replacement propeller 23 x 31 RH. Matched to the original, otherwise I guess it may be two propellers. Have emailed Princess parts, so will see whats available. Will also be contacting Clements today.
Anyone got a spare prop?
Thanks
 
Las fall I noted that the port hull zink on my Phantom 38 was nearly un used. It turned out to be a loose connection between the bonding wire and the hull zink itself. The shaft brush was ok. Like VP said it is important to check the connection end to end.
 
SC500 said:
Thanks to all. Based in Ipswich haven mariner. Having her checked today and will ensure all points mentioned are covered. Will post findings as soon as available. In meantime I'm trying to find out if I can buy a single replacement propeller 23 x 31 RH. Matched to the original, otherwise I guess it may be two propellers. Have emailed Princess parts, so will see whats available. Will also be contacting Clements today.
Anyone got a spare prop?
Thanks
Click to expand...

YOU DO NOT SAY WHAT YOU NEED BUT HERE IS AN IDEA OF WHAT THE COST WILL BE??

http://www.ebay.co.uk/itm/Right-Han...tEquipment_Accessories_SM&hash=item416515b3ed
 
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