Installing rigid boom vang - rivets or bolts?

[MarkSF]

I'm going to install a Garhauer rigid boomvang on my Bristol soon.

I've seen past discusssions on how to attach the hardware to the mast and boom. Seems like a choice between :

Thread the holes and use bolts. Stainless or Monel?
Don't thread them and use rivets. Then there are Stainless, Monel, or Alu rivets!

I've got some evil-smelling anti-galvanic corrosion compound that I've used in the past and will use to seal the threads/holes.

Seems like if the mast material were thin, rivets would work best. You need 4 or 5 threads for bolts to have an advantage. Is the mast that thick?

Right now there's no boom vang at all so whatever I use should be an improvement!

[overbored]

Originally Posted by MarkSF

I'm going to install a Garhauer rigid boomvang on my Bristol soon.

I've seen past discusssions on how to attach the hardware to the mast and boom. Seems like a choice between :

Thread the holes and use bolts. Stainless or Monel?
Don't thread them and use rivets. Then there are Stainless, Monel, or Alu rivets!

I've got some evil-smelling anti-galvanic corrosion compound that I've used in the past and will use to seal the threads/holes.

Seems like if the mast material were thin, rivets would work best. You need 4 or 5 threads for bolts to have an advantage. Is the mast that thick?

Right now there's no boom vang at all so whatever I use should be an improvement!

I have one installed on mine and it has stainless pop rivets. the ony thing about pop rivets is it takes a large rivet squeezer to do the large stainless rivets

[Faster]

Have you asked Gerhauer what they recommend? Did they provide the attachment fitting itself as well as the vang?

Some booms have sailtrack-like extrusions that can be used here as well. In any event this connection needs to be bullet-proof as the loads can be significant.

[tommays]

It would be rare for a boom a heavy enough wall thickness to Work well with screws

Even at .125 wall with a 10/24 screw you would only get 3 threads

[MarkSF]

Originally Posted by Faster

Have you asked Gerhauer what they recommend? Did they provide the attachment fitting itself as well as the vang?

Some booms have sailtrack-like extrusions that can be used here as well. In any event this connection needs to be bullet-proof as the loads can be significant.

Garhauer have some instructions but it just says to attach the bracket to the mast. The vang comes with two nice stainless steel brackets, one for the boom and one for the mast. They have six holes in, 3 on each side.

[Faster]

If you have the right tools, SS rivets might be best.

[RichH]

I have a garhauer rigid vang on a heavy boat with ~450 sq. ft. mainsail .... and Ive ripped out pop-rivets and threaded screws in the relatively thin boom section thickness.

Current configuration is with a backing plate with nuts welded to the plate and which was slipped into the boom from the aft end. The exterior Garhauer rolled brackets were centered over the holes, the backing plate (with nuts) 'worried' to being centered to the drilled holes in the boom, and bolts run in and torqued down; a royal PITA to get all the alignments correct .... no pull-out problems since.

The only way to go is through-bolts and nuts with backing plate, all the rest is 'flimsy' and subject to 'tear-out'. Kep-nuts and other 'blind' bolting/nut systems are available but require oversized holes in the boom.