Adding a boom vang to a 76 centaur

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josephcrawley
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Adding a boom vang to a 76 centaur

Post by josephcrawley »

I was given a block and tackle style boom vang and was wondering about adding it to my 76 centaur. Can I just make a fitting for the slot in the boom? Or should I use that horseshoe shaped fitting which would mess with the roller reefing function a bit?

Thanks
Last edited by josephcrawley on Thu Jan 04, 2018 11:26 pm, edited 1 time in total.
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Re: Added a boom vang to a 76 centaur

Post by TyroSailor »

What sort of kicking strap do you have at the moment? An ordinary tackle system is usual (mine is theoretically a 5-fold purchase but there's so much friction...). If you still have the original roller-reefing system in use it will interfere with any type of kicker - presumably you have a claw to use when the sail's reefed?

I'd seriously consider changing to a slab-reefing system at some point: as well as not interfering with the kicker it produces a far more efficient sail shape. But then you'd need cringles, which may not be in the sail....
Experience: That which would have been most useful five minutes before you acquired it.

Steve
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Re: Added a boom vang to a 76 centaur

Post by josephcrawley »

I need to get a new main for the boat anyway, the old one rotted in the cover, so switching to slab reefing is a good idea. The boat currently has no boom vang(or kicking strap ) at all. So the standard way with the roller boom is to use a claw that goes around the boom but allows the boom to still roll?

thanks
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Re: Added a boom vang to a 76 centaur

Post by Jolly Roger »

If you are buying a new main, then go the whole hog and fit slab reefing. You could add the slab reef fittings to your existing boom, but a new boom from Z Spars would be worth considering as it would allow all the reef lines and outhaul to be internal in the boom. Then add a stack pack for easy packing and your boat will be brought into the modern age.
Roger
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Re: Adding a boom vang to a 76 centaur

Post by josephcrawley »

No way can I afford a new boom. So can I use the boom grove to fit a attachment point for the vang or is that not strong enough? What alternatives would you recommend?

Thanks
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Re: Adding a boom vang to a 76 centaur

Post by Jolly Roger »

The groove was intended as a strengthening of the alloy section and is definitely strong enough for the load of a kicking strap. You will no longer be able to us the roller furling.
Roger
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Re: Adding a boom vang to a 76 centaur

Post by TyroSailor »

Yes indeed. Mine has the original boom with the reefing handle at the front but has a slab main (I wouldn't call it a reefing system) and the kicker fived in the groove underneath.

Anyone know how I can fit horns to the front of the boom?
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Re: Adding a boom vang to a 76 centaur

Post by Vegable »

Anyone know how I can fit horns to the front of the boom? (Plus how to make up a locking slider)

Yes I did it to my Renown. I made up a modified nut and bolt to replace the pin that held the boom onto/into the goose neck. I welded stainless steel horns onto the head of the bolt and on to the nut. I also drilled through the nut and bolt so that the horns were aligned to each other and put a split pin through the nut and bolt. (You then screwed the nut onto the bolt until it was very close to the gooseneck and then dropped the split pin through the nut and bolt). I also drilled through the centre of the bolt at the centre so that a second split pin went through the existing hole in the gooseneck which then held the horns in the upright position. When I did it first I had to use a prise bar to lever the horns outwards a bit so they didn't foul the gooseneck. - it was a good test of the weld too! Before you drill the centre hole align the horns so that the pull from the maisail reefing eyes - I used straps through the eyes to hook on the horns - pulls the horns up vertically so that you aren't putting a cutting force on the second/gooseneck split pin. By this I mean that when the mainsail halyard is tightened it isn't trying to turn the nut and bolt. A strong turning moment could easily sheer the split pin.
It sounds a bit complex but if you look at the existing gooseneçk pin and imagine hooks on it you'll see how it works. It was in the mid 90s that I did it so the memory is a little fuzzy and I don't have the boat now so can't show piccys. I can't remember what I used for horns but it will have been something like a shackle bent about a bit that had lost its pin.
For the boom slider in the groove underneath the boom I found that a modified U bolt that has the flat plate across the legs slides in nicely when you cut off the screwed legs, and the second bit of plate with the U bolt was drilled and tapped and a screw screwed into it and tightened onto the groove which held it in place in the direction of the thrust. I never did it but if you're certain as to where exactly you want the vang to be on your boom there's no reason why you can't drill and tap into the boom.
Mike
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Re: Adding a boom vang to a 76 centaur

Post by Jolly Roger »

Just been checking Z Spars web site as they will sell parts. They have three sizes of cow horns and think you will need one of these on this page.

http://www.zsparsuk.com/online-store/%3Foffset%3D120

It would be wise to chat with Z Spars as you may need to change your gooseneck fitting as well. Your alternative would be to chat with your local rigger and get him to do the change.
Roger
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Re: Adding a boom vang to a 76 centaur

Post by TyroSailor »

mmm - thanks Roger. And Mike.

It had occurred to me that I (or, more likely, someone skilled in working with stainless steel) could easily make something like that, but circular, to fit round the boom, maybe with a hose clip across the top to squeeze it tightly against the boom. I haven't done welding yet - and am reluctant to start on such a crucial bit of the boat!
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Re: Adding a boom vang to a 76 centaur

Post by Vegable »

I've just had another thought using a bit of lateral thinking.
Attached an eyed bit of rope to one of the spare holes in the mast step base using a shackle for instance. The other end of this rope has an eye somewhere near the gooseneck. Make up cloth straps with a metal ring which fastens through the reefing cringles on the mainsail luff so that they are there permanently. When you want to reef, lower the mainsail, shackle the rope to the ring in the cloth straps and then halyard will pull it tight.
You are now using the rope from the mast base to the gooseneck as the horns. No welding no drilling, 2 shackles and one ring and a couple of strips off the wife's wedding dress ('cos she won't be using it again), and bob's your uncle and it hasn't cost a fortune.
Mike
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Re: Adding a boom vang to a 76 centaur

Post by TyroSailor »

That sounds eminently feasible, Mike, and neater than my solution last season which was to have lines dangling from the luff cringles which I cleated low down on the mast when required. I think I'll try that - I have all the bits needed on board already! Thanks :)

In fact, a refinement would be to reeve a line between a luff cringle and the one at the gooseneck and lace it three times to get a purchase. This would make sure the luff was really tight, an important consideration in strong winds.
Experience: That which would have been most useful five minutes before you acquired it.

Steve
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