Corrosion around the gooseneck

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1. Corrosion

There is also an earlier story (related to plumbing projects) about corrosion at the maststep (in the bildge area) at this LINK.
The following story is about corrosion above deck between the aluminium mast/boom and the stainless fittings for the gooseneck, linking them together.

Corrosion between the gooseneck fittings to the main mast and boom

Under way in September 2008 between Fiji and Vanuatu I discovered, after a violent gybe, that the fitting of the main boom to the mast had broken loose on the starboard side. The reason was obviously corrosion between the two dissimilar metals; stainless steel and aluminium.

I had naturally long been aware that, at some point, I would had to do repairs to correct this kind of corrosion, not only at this particular area, but all over the mast - after all, Scorpio has been around for almost 30 years now. But I didn't think that the time was here yet and other maintenance projects have had priority - not so anymore!

Well in accordance with Scorpio's Law (see definition at this LINK), this incindent didn't occur last season while we were in New Zealand and doing major maintenance projects anyway, but instead in Vanutau, one of the lesser equipped areas of the world for these kind of projects.

As a preliminary measure while still under way, I took a line to a winch below the boom in order to eliminate the upward pull of the main halyard.

The aluminium material around the screws has been pulverized.
As a preliminary measure I tightened the
gooseneck fitting to a winch below it.

Fortunately we didn't have to face any adverse conditions on this trip and we got safely into harbour under reduced main.

On Tanna, our first island in Vanuatu there are no repair facilities, so any further measures had to wait until we reached the capital, Port Vila.

Well in Vila, I decided that a proper permanent repair would necessitate the mast to be pulled out of the yacht, which I hesitated to try to organize in this port. Because the fitting still appeared well secured to the mast on the port side I started to design a temporary solution.

The temporary solution

I did not want to break loose also the port side of the boom fitting trying to make a patch on the mast, thinking that I would only make things worse. The solution I finally came up with was pulling the fitting tightly to the mast using three straps around the mast tightened by ratchet type locking handles (the type used for securing loads on trucks). I found some heavy duty ones in a hard ware store and then modified the webbing straps using my Sailrite sewing machine.

Temporary solution: Looking forward on starboard.
Looking forward on port
Looking astern from fore deck.

This incident also turned out to become a routing decision maker: We aborted our plan to sail to the north of Papua Guinea and further to Indonesia and decided instead to sail to Australia to have the mast repaired - adding again an other year to our curcumnavigation.

I don't know how well my temporary fix will stand up to the challenges during the next two months before we arrive in Australia, but I hope for modest wind and sea conditions and, as the winds generally should be from abaft we should be able to sail well even without using the main if necessary.

Go to next page to see how we repaired the damage in Australia.