Boom Vang Attachment

[Kallisti]

last weekend I took my Grampian 26 out for the first time after a 3 year restoration!. The breeze was very light and we were just able to make way but every time we hit a wake or swell the boom would bounce and spill the little air we had. Also I was concerned about the strain on the mailsail/rigging caused by the bouncing boom, not sure if that concern is valid or not. Anyway, the reason this is in Gear/Maintenance is because i realized my obvious lack of a boom vang. I am looking at a soft block/line vang. The problem I am having is how to attach the bail to the boom as my boat has no attachment points for a vang. I am a little hesitant to start drilling holes through my boom without first procuring some advise.

So my questions to the oracles of Sailnet are these:

1. What is the best way to attach a bail to the boom? (bolt, rivet, etc.)

2. Will drilling bolt holes in the boom decrease structural integrity?

3. Can I also use a bail on the mast or do i need some sort of bracket?

4. The vang should be set at about a 45 deg. angle, correct?

Thank you, any advise is appreciated!

[BubbleheadMd]

1. Nut and bolt.
2. No.
3. Yes, you can use a bail. I do.
4. Yes, about 45. You want to have an angle of attack that gives you the most leverage, so you can tighten the vang. If you have an unfavorable angle, you'll want to add purchase to your vang tackle to give you the necessary strength to tighten it.

[Kallisti]

Thanks for the quick responce!

There is not much realestate between the step and the gooseneck so a 45 deg. angle may not be realistic. I was going to use 5/16 line and tackle at 4:1. do you think i should upgrade to 3/8 to accomodate the higher loads?

[aeventyr60]

Instead of drilling holes in your boom and attaching a boom vail, you can use nylon webbing to create a harness. This also will take up the shock loads. I use this method on a wood boom on a 37' offshore boat...

[jimq26]

Fastened all boom fittings with sheet metal screws (along with Locktite) They haven't come loose in 12 years of hard racing etc.

[tomperanteau]

Originally Posted by jimq26

Fastened all boom fittings with sheet metal screws (along with Locktite) They haven't come loose in 12 years of hard racing etc.

Agreed. Watch screwing into Aluminum, as it tends to gall. I installed mine with screws (a rigid boom vang) several months ago and have had her out quite a bit. No problems yet.

[Kallisti]

Thanks for all the advise!

Hey, jimq26, nice to meet another G26 driver!

I think I am going to bail the boom and mast with carrige bolts for the vang. But i think i will go machine screws for the boomkicker.

Again thanks for all the feedback!

[mitiempo]

Carriage bolts?

Drill the appropriate size hole and tap for the machine screw you are using. Short machine screws - 1/2" maybe. Use Tef Gel on the threads.

[MarkSF]

1. What is the best way to attach a bail to the boom? (bolt, rivet, etc.)

2. Will drilling bolt holes in the boom decrease structural integrity?

3. Can I also use a bail on the mast or do i need some sort of bracket?

4. The vang should be set at about a 45 deg. angle, correct?

Thank you, any advise is appreciated![/QUOTE]

1) I recently installed a boomvang (solid) and used 1/4" S/S rivets. I expect them to be stronger than a threaded joint in thin metal.

With a rivet, failure is when either the rivet snaps or the rivet rips the hole out. With a bolt in thin metal, it's when the threads shear.

It's interesting to go and look how the boat builder attached things to the mast and boom. How does the boom attach to the mast for example? Stainless rivets. Maybe they knew what they were doing?

You'll probably need need 1/4" rivets and an ordinary riveter won't cut it. You'll need something like this :
Amazon.com: Astro Pneumatic 1426 1/4-Inch Heavy-Duty Hand Riveter: Home Improvement

2) Yes, but so little it doesn't matter. There are already plenty of holes in the boom and mast where things are attached so two more won't make any real difference.

In case you want to go down that route, Garhauer sell solid boomvangs where they custom make the boom and mast brackets.

[ulferlingsson]

Originally Posted by mitiempo

Carriage bolts?

Drill the appropriate size hole and tap for the machine screw you are using. Short machine screws - 1/2" maybe. Use Tef Gel on the threads.

Machine screws should not be used in sheet metal. You can use a bolt through the boom and a nut on the other side, but don't expect the threads that you tap in the thin sheet metal will hold. Use sheet metal screws instead, they are made for that purpose. Or, go with rivets. Stainless is stronger at a given size, but since the boom is aluminium you may prefer that to avoid galvanic corrosion. Although, I haven't seen that as a problem even in the decades old boats I have sailed, so myself I will go for stainless rivets. If you are really concerned about strength, there are high-strength rivets that leave a core. Check out mcmaster.com for instance.