Corrosion on mast fittings

Thread starter #1
Hello all

Been lurking for a while, first time posting and I hope someone can help / advise me. I just bought a Laser with a hull number of 149xxx which puts it in the 25 or so years old range. I believe the spars are probably of the same vintage; on the mast at the gooseneck and vang plate (?) there is some corrosion due to stainless steel and aluminium being dis-similar metals. The mast is quite pitted at the corners of the fittings and I can't say what it looks like underneath them.

My question is should I drill out the rivets and replace the fittings directly opposite where they were originally ? (i.e. spin the mast 180 degrees ?) Depending on the damage, can I treat and fill the corrosion also ? What brands of fillers/treatments/rivets should I look for ?

Thanks in advance for your help.

BL
 

LaLi

Active Member
#2
should I drill out the rivets and replace the fittings directly opposite where they were originally ? (i.e. spin the mast 180 degrees ?)
No, you should NOT. That would double the number of screw holes at a given cross-section, which would seriously weaken the mast at those points (having holes on the tensioned edge of a spar is extra bad).

You might want to drill out the gooseneck and vang tang to see what the damage really looks like. You could even post a few pictures here. If it's really bad then the solution is to spin the mast 180° around its fore-and-aft axis, that is, "end-for-end" it. For that you need a new bottom plug and a relatively hard-to-find countersunk rivet, too.

_
 

torrid

Just sailing
#3
If you are already going to the trouble of drilling everything out, I would through-bolt the fittings when putting everything back together instead of re-riveting.
 
#4
My 2-cents worth.... corrosion of the rivet holes beneath the Vang tang on the mast caused the whole thing to break off. At an inconvenient time & place. Outgoing tide under the Golden Gate bridge. I got rescued OK, but since then when I see corrosion like that anywhere on a spar, I am replacing it.
 
Thread starter #5
Thanks LaLi, torrid and Eyeper for your input. Might save the pennies and buy new spars, given that they may be getting on 25 years old......
 

Rob B

Active Member
#6
They may not be worth saving. For your next sections there is an anti-corrosion paste you can get and put a layer between the dissimilar metals before riveting them together. Other than that just make sure to wash everything down with fresh water after every salt water dip.
 
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