Dan -

I understand this chain is 6 years old but I am finally getting around to fitting a boom vang and I had a question regarding the use of a T fitting instead of a swaged ball. Did your vang pennant use a T-fitting in conjunction with the key hole slot fitted to a later Ensign boom? Or did you have to fit a new slot "plate" appropriate to the T fitting. 

I would like to use a Dyneema loop and a Blue Wave Rope T-Eye - Large (https://theriggingco.com/products-by-category/blue-wave-rope-t-eye-large/ ) as my pennant. The diameter of the swaged ball used on a wire ensign vang pennant was 5/16" swaged (0.3125"); there is a Blue Wave rope t-eye with a head of 9MM or .354". Does that sound as if it might work with the key hole slot on my boom?

Thanks

Miles

I still use the swage keyhole slot on my original boom, but changed the 1/8" swage to a "T" vs. ball as it will not distort or pop out the slot. This way, no more drilling and keeps from having a bail hanging below. I think this was to enable roller reefing back in the day. I tried deck mounting the other end, but as the boom swings out, the tension increases. I now have a shackle fitted to the cleat that is slid into the mast track. This cleat has a hole to pass the shackle pin through and also acts as the downhaul.

Hi Fran. 

The point Jim makes about deck attachment for the vang is a good one.

I have seen deck attachments pull out of the deck because of the variable distance issues during gybes. The vang is best attached at the base of the mast in such a way that the distance does not change from fully extended mainsail trim from one tack to the other.

It is also good to have an efficient purchase system for the vang, 6:1 at a minimum, with a tail long enough to be trimmed or released at the primary winch position on the boat. This, because in conditions where the vang needs to be released to reduce power and heel on reaches, the crew needs to be aft at that location.

Stainless and aluminum despise each other. The problem is, aluminum should not be trusted by itself to carry strong vang loads. To prevent electrolysis between the two metals who have been forced into a long term relationship, tape the underside of any stainless fitting with electrical tape to form a gasket between the two metals. Use an Exact-O to trim any excess. Vang loads on the boom should be distributed over several square inches using a bale with a reinforcing, wrap-around strap. The image Vic sent shows a stainless bale connected to a stainless bolt that protrudes on either side of the boom. This is a good solution, but including a wrap-around (under the boom) stainless strap with attachment points in addition to the two bolt holes in the boom is even better from a load and longevity point of view. The load is then carried on a stainless on stainless interface... Purchase system to bale, to through-bolt, to wrap-around strap to boom.

In this system, the wraparound strap would be taped on the boom side with electrical tape to form the gasket.

Systems with the swage ball have a receiver fitting that may, or may not, have been treated properly to prevent electrolysis. I have seen booms break at that point because of weakness introduced by electrolysis.

My apologies for presenting a system that is engineered to the nth. Just trying to keep folks sailing and not repairing....



Best regards,

Bud Brown
#1085

ECA Rules Vice Commodore

The key hole idea sucks. Had one.

Another area to improve the vang is to ditch the metal insert in the mast where the bottom end attached. Replace it with a small piece of 3/16 or 1/8 spectra with small splices in each end long enough to go around the mast and thru itself. You use this as a choker just under the check blocks for the main and Genoa halyards then attach the vang to it. Could also just use a loop of spectra doing the same choker or luggage tag style attachment. If your vang is attached to the deck it's a good idea to move it to the mast base so it does not get overtight when the boom swings out for a reach or a run.

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I have a vang keyhole in my boom but no vang key. The only keys I see On line are for lasers. Are they right sized for the ensign ? Other alternatives ?