There’s nothing worse than having to cut your sail short because of a broken spar. Most commonly on the Laser, the damage will happen at the gooseneck or the vang tang on the bottom section. This happens because those metal parts are dissimilar metals; the mast is made of aluminum and the fittings are made of stainless steel. Dissimilar metals and alloys have different electrode potentials, which through an electrochemical process leads to corrosion. It is important for preventing spar corrosion.
Prevention is something that should be done by everyone, even if you’re not in the tropics, and especially if you sail in salt water.
Corrosion is the gradual destruction of metals by chemical reaction with its environment. This process is accelerated by electrolytes, the biggest culprit being salt. In Mexico, we’ve become well versed in this game, as the air is moist and salty. Our spars spend their time in a pretty harsh environment.
It is possible to prevent this process, though. Laser spars come out of the factory with a preventative coating already applied. Over time corrosion still can and will develop, especially in a salty and humid environment.
Preventing spar corrosion is something that should be done by everyone, even if you’re not in the tropics, and especially if you sail in saltwater.
Lanacote: Developed primarily for threads and screws, but it works very well in this application. This is what we use at ISA, and being in one of the harsher environments for spars, we've found we've had pretty good success.
Tef Gel: It’s not cheap but seems to do the trick! The one big advantage of Tef-Gel is that it can be bought in small quantities - a lot of these products will "cure" after a while once the package has been opened.
Duralac: A favorite, though it’s not cheap either. We've used this one on big boat rigs and it works great. It applies with a brush so you can get a lot of good coverage, and lasts a long time.
There are plenty more products out there - just check the label to make sure they were designed for dissimilar metals. Most of them are made for the marine industry, as that’s where the issue seems to be the most pervasive!
When installing the gooseneck and the vang tang, always use 3/16 stainless steel rivets. Apply these pastes or gels quite liberally, covering as much area as possible, including the rivets.
Always rinse everything on the boat after each sail with fresh water, paying special attention to any metal.
