Hello sleuths - Can you tell me why my rudder broke off at sea? - SailNet Community
Reply
 
LinkBack Thread Tools
post #1 of 73 Old 04-18-2007 Thread Starter
Senior Member
 
Zanshin's Avatar
 
Join Date: Aug 2006
Location: Germany
Posts: 2,295
Thanks: 0
Thanked 29 Times in 27 Posts
Rep Power: 9
 
Hello sleuths - Can you tell me why my rudder broke off at sea?

I finally got my 2003 43" Jeanneau hauled today to replace the rudder. The solid metal stock broke off right at the through-hull and after dropping it and doing a quick bit of cleaning this is what the remnant looked like:




There are no sharp edges, but I have been in a marina for the past 4 weeks waiting for the replacement part to arrive. I was surprised at the copper buildup and my first thoughts are that I might have an AC power issue and that the copper has been plated from the surrounding bottom ablative coat.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Zanshin is offline  
Quote Quick Reply Share with Facebook
Sponsored Links
Advertisement
 
post #2 of 73 Old 04-18-2007
.
 
Join Date: Nov 2006
Posts: 10,851
Thanks: 0
Thanked 5 Times in 2 Posts
Rep Power: 13
         
Looks like galvanic corrosion did it first, as it was at the thru hull. Then as you sail, and turn, torsion forces weakened it.

If it was impact it woud "tear" towards on side

The copper was deposited after.
Giulietta is offline  
Quote Quick Reply Share with Facebook
post #3 of 73 Old 04-18-2007
Senior Member
 
donrr1's Avatar
 
Join Date: Oct 2002
Location: Middle River, Md
Posts: 180
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 13
 
It looks too smooth to be from an impact as Giu says, but it also looks too precise to be galvanic corrosion. The rest of the shaft doesn't appear to be pitted at all. I don't know...

Don

I love being on an Even Keel WTF are YOU lookin at?????
donrr1 is offline  
Quote Quick Reply Share with Facebook
post #4 of 73 Old 04-18-2007
moderate?
 
camaraderie's Avatar
 
Join Date: May 2002
Location: East Coast
Posts: 13,877
Thanks: 0
Thanked 3 Times in 3 Posts
Rep Power: 16
     
Wow Zan...that is something I've never seen. I agree with the probability that it is galvanic in nature. My guess is we don't see any ypical pitting cause what you have was above the waterline. The additional time in the marina probably took care of ragged edges with the copper plating!
Sounds like you need a good marine electronics guy to check things out before you put another shaft in the water.
That picture should be in the galvanic corrosion hall of fame!
camaraderie is offline  
Quote Quick Reply Share with Facebook
post #5 of 73 Old 04-18-2007
Telstar 28
 
sailingdog's Avatar
 
Join Date: Mar 2006
Location: New England
Posts: 43,290
Thanks: 0
Thanked 14 Times in 12 Posts
Rep Power: 14
         
It is unfortunate that we can't see what the other piece looked like. That piece would probably give us a much better picture of what had happened.

Sailingdog

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Telstar 28
New England

You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
a boat to the sea you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps
her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.

—Cpt. Mal Reynolds, Serenity (edited)

If you're new to the Sailnet Forums... please read this
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
.

Still—DON'T READ THAT POST AGAIN.
sailingdog is offline  
Quote Quick Reply Share with Facebook
post #6 of 73 Old 04-18-2007 Thread Starter
Senior Member
 
Zanshin's Avatar
 
Join Date: Aug 2006
Location: Germany
Posts: 2,295
Thanks: 0
Thanked 29 Times in 27 Posts
Rep Power: 9
 
The rest of the shaft is unmarked and smooth, with the exception of some pitting along the waterline which I noticed by dragging my fingernail across it. I couldn't find the actual breakage lines when the rudder broke off - as noticed already the whole bottom of the shaft is rather smooth, almost as if the corrosion happened over enough time to prevent sharp edges.

I am a bit surprised that the copper deposited only on the end of the shaft, as if the exposed surface was acting as a cathode.

The rudder snapped off in relatively mild conditions and with little torque applied. I couldn't salvage the rudder portion, but do recall that I saw a couple of inches of steel stock sticking up - which might indicate that the rudder fibreglass bottom had water in it, otherwise I would only have seen the bottom of the rudder above the waves.

My first thought when I saw the discoloration was that someone had (badly) welded a broken rudder back together, but that certainly didn't happen.

Addenda - Cam: The portion in the picture was under the waterline by a couple of inches, in the top section of the picture you can vaguely see the waterline. I have more pictures that I can post if people are interested enough that might help in the analysis.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Last edited by Zanshin; 04-18-2007 at 07:26 PM.
Zanshin is offline  
Quote Quick Reply Share with Facebook
post #7 of 73 Old 04-18-2007
Telstar 28
 
sailingdog's Avatar
 
Join Date: Mar 2006
Location: New England
Posts: 43,290
Thanks: 0
Thanked 14 Times in 12 Posts
Rep Power: 14
         
Corrosion might have indeed worn the sharp edges away. How long was the boat in the water after the rudder broke??

Sailingdog

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Telstar 28
New England

You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
a boat to the sea you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps
her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.

—Cpt. Mal Reynolds, Serenity (edited)

If you're new to the Sailnet Forums... please read this
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
.

Still—DON'T READ THAT POST AGAIN.
sailingdog is offline  
Quote Quick Reply Share with Facebook
post #8 of 73 Old 04-18-2007 Thread Starter
Senior Member
 
Zanshin's Avatar
 
Join Date: Aug 2006
Location: Germany
Posts: 2,295
Thanks: 0
Thanked 29 Times in 27 Posts
Rep Power: 9
 
Here is picture taken immediately after the haulout from directly below the rudder through-hull


A picture comparing old vs. new


This is a full frontal picture prior to any degreaser and acetone


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Last edited by Zanshin; 04-18-2007 at 07:49 PM.
Zanshin is offline  
Quote Quick Reply Share with Facebook
post #9 of 73 Old 04-18-2007
Telstar 28
 
sailingdog's Avatar
 
Join Date: Mar 2006
Location: New England
Posts: 43,290
Thanks: 0
Thanked 14 Times in 12 Posts
Rep Power: 14
         
Did it break off right at the point it exits the rudder blade?? It looks like it actually broke off inside the rudder itself, not at the point it exits the rudder, based on the lengths.

Sailingdog

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Telstar 28
New England

You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
a boat to the sea you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps
her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.

—Cpt. Mal Reynolds, Serenity (edited)

If you're new to the Sailnet Forums... please read this
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
.

Still—DON'T READ THAT POST AGAIN.
sailingdog is offline  
Quote Quick Reply Share with Facebook
post #10 of 73 Old 04-18-2007
.
 
Join Date: Nov 2006
Posts: 10,851
Thanks: 0
Thanked 5 Times in 2 Posts
Rep Power: 13
         
Galvanic.....
Giulietta is offline  
Quote Quick Reply Share with Facebook
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the SailNet Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.


User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Forum Replies Last Post
Building a Rudder Newport 30 Armchairprotest Gear & Maintenance 5 04-07-2009 01:11 PM
Emergency Steering John Kretschmer Seamanship Articles 0 03-08-2002 07:00 PM
Emergency Steering John Kretschmer Gear and Maintenance Articles 0 03-08-2002 07:00 PM
Emergency Steering John Kretschmer Cruising Articles 0 03-08-2002 07:00 PM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome