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S&S Swan Maintenance - Mast + shoe corrosion
11 March 2010 - 16:11
#1
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christophe montcerisier
Join Date: 27 August 2009
Posts: 44

Mast + shoe corrosion

One more discovery while working on a renovation plan of my 41: the bottom of the mast appears corroded as well as the shoe.

I have looked at previous threads on the corrosion of the bottom of the mast and it seems that best solution is to insert a stainless steal piece of metal inside the mast to reinforce it. Is my understanding correct?

On the second point, should I replace the shoe? Does any one know if Nautor Swan spare parts still have extra shoes available? Ate there any other technical solutions to make sure the shoe is correctly restaured? Is there any particular piece of information I should relay to the technicians to help them carry out their work in the best possible manner?

I have attached some pictures.

Thanks in advance for any feedback.

Christophe - Swan 41 #11
12 March 2010 - 09:23
#2
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philippe
Join Date: 16 February 2007
Posts: 199

Bonjour Christophe,

The problem of the corrosion of the mast foot is well known and well discussed in this forum. Look for a thread that was started on the 18th of Janaury. All information you need is there. What you should not do anyway is to insert stainleass steel in the foot of the mast. It will corrode even more. Insert aluminium.

Cheers

Philippe (47/050 Farouche)
12 March 2010 - 17:15
#3
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kamo
Join Date: 22 November 2008
Posts: 8

Hi Christophe,
from what I see in the pictures the situation is not so bad.

I don’t think you need to replace the shoe. You have just rust in a part always wet.
I think your mast has already been repaired by inserting a piece of aluminium profile attached with rivets. It looks a good work and you have not a lot of corrosion.

I suggest you to clean (remove rust and aluminium oxide) and paint ALL the metal parts whit Duralac.

The best should be to find a way to keep this part dry…

Regards Federico

12 March 2010 - 21:21
#4
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ludovic
Join Date: 25 July 2008
Posts: 30

Dear Christophe,

You will find my experience just on the second page of thi forum.  I just uploaded pictures of the actual situation.

Ludovic (Rum trader 47')
01 April 2010 - 14:08
#5
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cosmolittle
Join Date: 02 March 2007
Posts: 83

Dear Christophe,

  I took the mast out of my 41 last winter, and had similar mast corrosion. My mast had not been sleeved, and as the corrosion was not too bad I did nothing about it. However I had noticed that the shoe was always full of water ( usually rainwater) due to the drain holes being rather inadequate, so while the mast was out I drilled some 10mm holes right through the shoe and galvanised plate.  I also added a thin plastic washer to the base of the shoe, and a plastic sleeve round the mast base to try and reduce galvanic corrosion.

 

regards Cosmo Little

 
03 April 2010 - 00:52
#6
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Candy Morganson
Join Date: 23 February 2008
Posts: 15

Bonjour, Christophe. Last summer we pulled our mast at the KKMI yard, www.kkmi.com in Richmond CA USA & found significant corrosion on the bottom of the mast. We ended up having the yard remove about an inch & then build a plug of high tech composite to restore the mast to it's original length. The plug also totally isolates the steel mast step/shoe from the base of the aluminum mast so we should never have the problem again. We did not have rust on the steel step/shoe. I'm sure if you contact Jock Maclean, our project manager, jock@kkmi.com you could get the specifications & details of how the repair was made. I have attached photos of the damage & new plug. There were drain holes put in the plug before the mast was restepped.
03 April 2010 - 22:19
#7
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danielefua
Join Date: 30 January 2007
Posts: 461

Hi Candy,
your solution looks very clever and it would be very helpful to all of us if you could give more specifications on the used hi-tech composite.
Beside this, if not already done, I would strongly suggest restoring the electrical continuity between the mast and the keel by adding a properly studied conductor that will not corrode the mast aluminum.

Daniel, 411-004
05 April 2010 - 01:04
#8
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Candy Morganson
Join Date: 23 February 2008
Posts: 15

Hi, Daniel. I have no idea exactly what the composite is that was used to construct the plug but it may be knows as "G-10". I do know it is very heavy for its size. That is why I referenced KKMI & Jock in my original post as they obtained the material & did the work. I'm sure he could provide design details as well as confirming G-10. We weren't there when they restepped the mast but with their attention to detail as a Swan yard, I'm sure it's tied into the bonding system.

Candy, 44, #45

 
05 April 2010 - 07:28
#9
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the professor
Join Date: 02 January 2008
Posts: 1547

Dear Candy and Daniel

This is G-plate, glass reinforced epoxy laminate with a high fibre content,  available in sheets.

Stitched rovings and RTM or vacuum bagging required to get similar properties if you attempt to make your own version.

On one Swan the corroded mast step was replaced with a structure built of G-plate, making it corrosion-free.

Kind regards

Lars
04 March 2011 - 18:44
#10
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kamo
Join Date: 22 November 2008
Posts: 8

you can see how I solve the corrosion mast problem on my 37..
Regards Federico
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