Posted by: August Sandberg | 22/07/2012

Tærbitt

Vegard, laughing at the face of danger.

Vegard, laughing in the face of danger

As we hoisted Værbitt out of water last week, we were met by a terrifying sight. The saildrive and parts of the propeller was eaten away by corrosion. The worst case any of us had ever seen. Like a damp chocolate chip cookie, the drive crumbled between our fingers. It was a miracle that the oil had not leaked out, which would have been catastrophic.  What was supposed to be a relaxed week with anti-fouling and polishing was about to turn into a thriller.

Luckily, we had bought a used spare drive two years earlier. We removed the corroded drive, and prepared the spare for attachment.  But the new drive didn’t feel right. The crankshaft was way slower than on the one we had removed, and it made a weird clicking sound. We feared that the bearings were broken, and took it to Volvo Penta dealer Bjordal & Madsen in Bergen for them to have a look at it.

Sad propeller hub

Meanwhile, we concentrated on the propeller. the blades were fine, but the hub was badly attacked. Jørgen, Værbitt’s hardware magician, repaired it with steel epoxy casted around a rubber tube.

After two days and 1400 kroners, Bjordal & Madsen had figured out that there was nothing wrong with our spare drive. The clicking was totally normal, and there should be nothing to worry about. We mounted it on the boat, sealing it with screws and sikaflex, and then attached the propeller. With smiles on our faces, we let the drive spin. Then we noticed the propeller bobbing up and down ever so slightly. After some measuring, we found that the drive shaft was bent.

Vegard takes on the saildrive’s screws for the third time

Wondering how hard it would be to get a job at Bjordal & Madsen, we disassembled the drive again. We found the problem to be the outer part of the propeller shaft. Luckily, we found a replacement in the corroded drive. It was in perfect condition, and Vegard exclaimed that turning it was the best metal related experience of his life. And that says a lot.

We opened up the saildrive chassis and replaced the broken part. This time, all was well. Happy and relieved, we went home to make an angry phone call to B&M. And a very nice one to Norske Sjø insurance.

Father and son inspecting the finished job

What we learned

  • Galvanic corrosion can be surprisingly fast. Remember to check your zinc often, especially when moored in a marina with possible stray currents.
  • Certified mechanics do make mistakes.
  • It’s very handy to stock up on spare parts.
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Responses

  1. […] Vetus 33 from 2006. It’s got a 50ah alternator and  indirect water cooling. It powers a newly changed Volvo Penta 110 saildrive with a home-casted two-blade folding propeller. It’s quite a large […]


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