So the shrink wrap came off today and the maintenance/upgrade slog has begun. My early spring projects includes rebuilding the boom. Aluminum corrosion has begun to be a bit noticeable especially on the boom ends, the out-haul blocks need to be replaced and I want to replace the out-haul cable with line. The boom itself seems in good shape but some corrosion on the removable ends has removed some anodization.

I have removed corrosion with a wire brush and cleaned up the boom ends but what should I do to paint/protect them from continued corrosion? Thinking aluminum etching primer and enamel before re-installation?

many spring projects to go but this is a start.

Following this with interest, I have similar corrosion on my boom ends. In fact I've already had one failure of the boom-gooseneck joint as a result.

So I hit the boom ends with crushed walnut from the media blaster, took care of the flecked old primer and cleaned it up pretty well. Washed and rinsed with vinegar (acid neutralizes aluminum corrosion apparently). Two coats of aluminum etching primer and three coats of flat black enamel later... it looks pretty good.

I've re-installed the sheaves and now I'm attacking the corroded screws and bolts in the boom itself intending to clean it up and give it a coat of enamel as well. Most screws and bolts are corroded into place so I'm soaking them with sprays of pb blaster and wd-40. When I take the torch to them, hopefully they'll free up.

The main sheet attachment half-loop bolt thingy-mabob (that's the technical term) has worn its hold into an elliptical gap so I think i'd like to either drill a new hole or use a soft tether (like the new maxi boats!) to re-secure the main sheet connection i.e. Should I pass the webbing for the soft tether through the worn holes or over the boom itself?

Just thinking out loud

Josh,

Check out this old post with the Rhapsody boom repair.

Thanks Bill, I will be ordering those plates (though secretly I still want to put webbing through them). It seems like the wire should go before it makes the sheave unuseable (another 40 bucks to rig rite), can it be switched out for just 5/16 staset-x or spectra? Does it matter if there is a little stretch in the out-haul (you can just pull it tighter right)?

I think that Spectra or Dyneema would work just fine to replace the wire. I have Dyneema on my J/109.

Project looks good, by all means eliminate the wire and use 12 strand Dyneema for the outhaul tail. Invest in some small blocks to increase the outhaul purchase. I took Bill's advice years back in my Boom Bail makeover.

As for the webbing straps, no personal experience but I saw these a few years back and thought Dyneema Climbing Slings might be an inexpensive solution. Unclear how class rules would apply.

If you go with webbing straps, do not go through the holes as you will have too much potential for wear. They should go around the whole boom. You will also need to devise a way to keep them from sliding.

What I do not know is if a strop around the boom will increase the risk of the boom dentine/kinking during a hard slam under the strap, versus how the forces are transferred on a through bolted bail.

The yankee engineer in me tends to think that load distributed around the boom via strap would spread force over a larger surface area than the bolt, which has limited contact when compared to a strap. Thanks for the idea Bob, I'll be headed over to east coast REI (EMS) to see what they have for webbing. I'm thinking that I can pass a small loop through the old bolt hole and around the webbing to keep it placed where it is supposed to be. Mostly, I just think the strap looks cool, modern maxi-boat racy.

I'll be converting to strap on Koesh when she goes back in. That'll be a while, though...drilled some holes to check the wet areas below the turn of the aft bilge and found compost. Got the new balsa (yeah....going back) and I'll be carving away on the outer skin as soon as it's warm and dry enough here in Oregon.

If you go to strap, a friend of mine recommends using a double figure-eight as per climbing practice for tying it in. VERY secure!