Fw: [Amel Yacht Owners] Prop Shaft Electrolysis


Anne and John Hollamby <annejohnholl@...>
 

 
 

Sent: Saturday, March 29, 2014 4:06 PM
Subject: Re: [Amel Yacht Owners] Prop Shaft Electrolysis
 
Hi Kent,
I cannot even imagine the problems and expense of changing the propshaft. The pic that you have shown us looks horrendous but hopefully that is the whole extent of the damage and if so the reduction in strength should perhaps be relatively unimportant. Just in case the damage is more extensive I suggest that you have someone put the engine in gear and turn it over by hand using a lever between the bolt heads on the pulley for the fan belt and listen to find out if the bearings/gears in the unit have seized up. This is unlikely as presumably the engine was used recently to get the boat ashore.
If you examine the wearing out bush you will find that there is an O ring inside it and this is what keeps the oil in whilst the bush turns with the prop shaft and the three oil seals on the outside of the bush keep the oil in when the shaft and bush is turning. Now you need to give the shaft a ‘colonoscopy’ to see how far the shaft is damaged. Car part vendors sell an endoscope that is small enough to fit down the dip stick tube for about €80 euros and this should do the job. If you are unlucky and the shaft is pitted further in than the existing O ring position look further on and you may find that there are positions where an O ring could make a seal and if so then when you get a new bush you can have a new
groove cut for a second O ring to do the job. If you sleeve the old wearing out bush as I have done on mine  your shaft problem may be solved without even getting a new bush.
There is clearly an electrolysis problem either arising from your boat or the marina,neighbours and this must be resolved. You certainly need to get a really good marine electrician to check your wiring and to install a galvanic isolator.
I look forward to hearing the result of your endoscopy examination! Meanwhile I suggest that you get a copy of Nigel Calders book on boat maintenance, It should become your bible.
Now I must go down to the yard to remove my prop (with trembling hands).
 
                            Best wishes,  Anne and John,  Bali Hai,  SM319,  Malta 
 
Sent: Saturday, March 29, 2014 4:29 AM
Subject: Re: [Amel Yacht Owners] Prop Shaft Electrolysis
 
 

Yeah, looked there too.


On Mar 28, 2014, at 11:21 PM, sailormon <kimberlite@...> wrote:

 

Kent,

If I recall correctly, it is not in the books with all the manuals it is (I believe) in the owners manual with all the colored photos.

Sorry—but I am not on the boat.

Eric

From: amelyachtowners@... [mailto:amelyachtowners@...] On Behalf Of Kent Robertson
Sent: Friday, March 28, 2014 11:04 PM
To: amelyachtowners@...
Subject: Re: [Amel Yacht Owners] Prop Shaft Electrolysis

 

I looked through everything I have , Eric. I would swear I've seen that drawing, but I can't find it.

Kent


On Mar 28, 2014, at 10:59 PM, sailormon <kimberlite@...> wrote:

 

Kent, In the back of the owners manual there are pages that fold out with plumbing diagrams, etc and also drawings of the bow thruster, sail drive and many other drawings.

Do you have an owners manual?

Fair Winds

Eric

Kimberlite SM 376

From: amelyachtowners@... [mailto:amelyachtowners@...] On Behalf Of Kent Robertson
Sent: Friday, March 28, 2014 10:55 PM
To: amelyachtowners@...
Subject: Re: [Amel Yacht Owners] Prop Shaft Electrolysis

 

I don't have it aboard, Eric. If anyone had it I'd appreciate it if you'd email me a copy . Karkauai at yahoo dot com.

Thanks again.

Kent


On Mar 28, 2014, at 8:49 PM, sailormon <kimberlite@...> wrote:

 

Kent,

I just looked for a drawing of the C drive. It must be in the books on Kimberlite.

From memory I believe it will be a big job.

Sorry,

Eric

From: amelyachtowners@... [mailto:amelyachtowners@...] On Behalf Of Kent Robertson
Sent: Friday, March 28, 2014 8:30 PM
To: amelyachtowners@...
Subject: Re: [Amel Yacht Owners] Prop Shaft Electrolysis

 

Thanks Eric. Yeah, it's pretty scary.  Lucky we didn't lose the prop.  I just discovered it and haven't talked to the marina yet.  I'll have to find out more about the galvanic isolator...good idea about just turning on shore power once in a while.

Any idea how to remove the prop shaft?

I'm going to have an electrician go over the boat looking for stray currents...any suggestions about that process?

Thanks

Kent


On Mar 28, 2014, at 8:24 PM, sailormon <kimberlite@...> wrote:

 

Wow !!

That looks awful.

I use a galvanic isolator on my AC circuit and also have the pedestal turned on only one day a week. So far in 3 months in the marina in the Caribbean I have used one kilowatt of electric.

There is a small zinc on the line cutter, and of course the 2 big ones on the rudder.

I am very sorry for the condition of your prop shaft. I believe there should be a drawing of your c drive in the owners manual . I believe replacing the shaft is a big project. It is also possible that a neighbor is putting AC into the water.

Did you have the marina check your AC outlet on the pedestal and the water around your boat?

Fair Winds

Eric

Kimberlite SM 376

From: amelyachtowners@... [mailto:amelyachtowners@...] On Behalf Of karkauai@...
Sent: Friday, March 28, 2014 3:01 PM
To: amelyachtowners@...
Subject: [Amel Yacht Owners] Prop Shaft Electrolysis

 

I have just hauled Kristy out to repaint the bottom after 2 1/2 years.  She's been sitting in the water in a marina at Brunswick GA for the last 2 years where I've hired a diver to clean the bottom and replace the zincs as needed every 4-6 weeks.  I was surprised to see no zinc on the prop when we hauled out, and dismayed to see severe electrolytic corrosion of the prop shaft when I started changing the seals. I posted a pic at the KristySM243 folder https://groups.yahoo.com/neo/groups/amelyachtowners/photos/albums/948071197/lightbox/1877878820
I need advice on what is involved in removing the prop shaft.  Is it necessary to remove the bottom of the drive aft of the keel?
I guess I'm going to look into isolating the boat electrically.
Sigh,
Kent
SM243
Currently Tiger Point Marina, Fernandina Beach, FL