DaySailer.org Forum

Putting bails on a boom for attaching mainsheet blocks (mid-boom sheeting). The bails attach with 1/4" bolts. Would it be beneficial to drill oversized holes and insert bronze flange bushings? All I can imagine is the threads on the bolts slowly sawing into the aluminum over time. The bushings would be sort of "sacrificial" in that regard, and they'd apply the force pulling on the holes over a larger area. Thoughts? Experiences?

Thanks!

my boom has a bail on it, looking thru photos I have archived for reference quite a few have bails or a rail. you could rivet them on with pop rivets

Not necessary.

Bronze would add dissimilar metal. Nice corrosion promoter unless you electrically insulate. So there's that, too.

I have a bail for my vang I riveted to the boom. Works fine with simple pop rivets - except: I made the mistake and didn't align it perfectly with the direction of the pull. Now the bail is bent (!) but the rivets still hold. Held for several seasons, and that points to the fact that loading rivets on shear is where they are strongest.

The bails are meant for 1/4" bolts. I was hoping to prevent the bolt threads from working against the aluminum, and increase the area on which the force is applied to the boom.

You need to get a bolt that has no threads for the width of the boom?

The 1/4" isn't a problem, I think.

I'm sure you can look it up at what loads you should expect it to pull out. For a vang, people tend to dimension them for working loads of around 800lbs. If you can find some links that show that this is more than a 1/4" bolt can hold on shear in aluminum, I'm sure we'd all love to see them. I'm not an engineer, so I don't have anything like that bookmarked.

There's not a lot of rotation under load, so even if the bolt is forced to turn with the bail, I don't think it will do much grinding.