Practical use of Boom Vang

[R. Young]

My hunter 37 (1987) never had a boom vang, what am I missing?It seems (by feel) that under all points of sail, the boom does not rise very much - or at least I do not notice it. The boom is somewhat heavy & the main control is well aft. When I had a Capri 22, I did notice the boom moving in the vertical place, especially when on a run - dont seem to notice it now. How critical is this control? RogerHunter 37 - Destiny

 

[Paul]

Not absolutely necessary...

Look at a picture of a Chinese junk, or pictures of old schooners and you don't see vangs, so they are relatively new.Part of the reason for the recent appearance of vangs is that spars used to be made of wood, so booms were so heavy to start with that nothing was required to pull them down beyond gravity.A vang is required to keep the boom from rising on any point of sail from a reach to a run. On my boat, the boom rises noticably on these points of sail if the vang is slack.Closer to the wind, the mainsheet pulls down the boom and the vang is much less important.What happens if you don't have one? When the boom rises as you are sailing off the wind, the leech opens and spills air, and you go 5.75 knots instead of 6 knots. Is it a big deal? Probably not. Would you get there a little sooner if you had one? Maybe.Paulsv Escape Artisth336

 

[Tom]

Sail shape

Besides protecting from a lifting boom, a vang can help you flaten your main in heavy weather. I have a Garhaure (sp?) solid vang and it really helps alot in changing sail shape.

 

[Joe]

Vang

Besides being an important mainsail control, the vang is handy to have around the boat. If it's rigged with snap shackles for a quick disconnect, you can use it as a temporary preventer, outboard lifter or even to assist in MOB recovery.

 

[Don Guillette]

Roger: The boom vang controls draft position (along with the cunningham, mainsheet, mast bend and outhaul) and twist. Twist is controlled by the boom vang and the outhaul and it is very difficult to get the twist out of your main by using only the mainsheet but if that is all you have you have to make the best of it. The boom vang has two functions. One is to keep the boom from rising, which would cause the mainsail to luff and the second function is to pull the boom down. It is very important when you are sailing off the wind because the boom has the tendency to want to rise up. This “rising up” is difficult to control with the mainsheet only because the farther out the boom goes, the greater the pulling angle for the mainsheet and the less effective it becomes. Try it the next time your out sailing. Push the boom all the way out and look at the pulling angle your dealing with and you’ll see what I’m talking about. By applying pressure on the boom vang and pulling it down you cause the draft position to go forward and you reduce twist. The opposite is true when you let it off. The draft position moves aft and twist increases. When you apply pressure and ease pressure on your vang is another story.Since you don’t have a boom vang the following won’t work for you but for mates reading this thread that do have one, the next time your out sailing crank on your boom vang and mainsheet and watch what happens to your twist and draft position. You’ll actually see it move. Cool, huh!!!