Thom Stewart scribbled thusly:
Since the Vang; Solid or Rope, What ever, has been kicked around as a
Hoisting Device, which it isn't let's talk about what it is for.

Why isn't the Vang a Hoisting Device? The Hunter 19 vang was a 3:1
purchase on swivel pelican hooks, originally supplied as the mainsheet
which it was marginally suitable for. We used it with a gin pole for
raising the mast, on those few occasions I didn't lever it up by hand
(carefully lifting at the 25% mark).


Why is it necessary?

It isn't "necessary." It's fully possible to sail without a vang.

....When do you use vang pressure? To do what? If it's
good sometimes, why not all the time?

How much tension should be put on a Vang? Can a strong Deck Ape over
apply tension by hand?

Yes, definitely.


You first Doug. It is a Racers gimmick. Tell us why?

A vang is not a racer's gimmick. It's a very useful tool for controlling
the sail.

OzOne wrote:
It's all about controlling the position of the boom and all that that
entails be it upwind, downwind or gybing.

What a great phrase, "all that that entails." We've had some discussions
here about sail twist, is this the time to revisit the subject?
Basically, the boom vang controls how far the boom rises, which
influences twist. It also, on some boats, keeps the end of the boom from
catching on the backstay in gybes.

BTW let's distinguish between a VANG and a preventer.

On small boats it can be used to induce mast bend, not much joy when
your mast is a tree trunk

It can bend the boom too.

Fresh Breezes- Doug King