The Vang: How Much is Too Much? (D. Schwenk, May 2007)

The Vang: How Much is too Much?

 

The 2007 Parramore was sailed in 15-20 knots, with puffs going above that.  We had plenty of breeze, plenty of waves, some wake and with 9 windward leewards in 2 days, plenty of opportunities to improve our performance to windward in a breeze.  Onshore we had lots of talk about how to set up for speed in the situations, and lots of talk about use of the boom vang.  (For anyone that has not read my prior article Upwind in Waves and Wake, that talks about the other stuff that I think about in breeze).   Dan Phelps of Spinsheet Magazine was out taking photos for an upcoming article, so we now have lots of photographic fodder to use in looking at the question. 

First – a few guidelines for the vang IN BREEZE (are not talking light a variable, here!) 

  1. Upwind: After mainsheet, vang is the control I use most.  Here is what I use to know when to change it:
    1. If the boat feels wild, and hiking and sheeting are hard or I cannot keep it flat with a reasonable level of hiking – vang on.  
    2. If the boat feels stalled, dead, too quiet, or inexcusably slow – vang off.
    3. If the main shows overbend wrinkles extending back more than half way to the clew, vang off (or if you are overpowered, try more Cunningham and a block in front of the mast, and then more vang – get the wrinkles right!).
  2. Windward Mark – EASE VANG ON FINAL APPROACH so you do not break your boom. 
  3. Down Wind: Vang on so the top batten is parallel with the boom.
  4. Leeward Mark: tension as soon as you are up to speed.
  5. Starts and Tacks: Its hard to accelerate with vang on, so you may want to ease until you are up to speed. 

Second – if you are going to effectively use the vang, the control needs to be accessible from the rail, and not be in a place that your crew or you are sitting.  I have a swivel on the centerboard trunk – others run it double ended to the rail. 

The Pictures tell the story….Thanks again to Dan Phelps, Spinsheet Magazine.

vang1

Team Schwenk upwind – note clearly bent boom, outhaul hard out.  From inside the boat, I cannot see this bend in boom, I am working off of the “feel” of the boat, discussed above.

vang2

This photo is more what I see from inside the boat.  Outhaul showing a hard shelf, overbend wrinkles extending back about halfway.  We have a fair amount of Cunningham on here as well, and the sail is tied forward at the gooseneck. 

vang3

Team Lochner coming upwind.  To my eye, this is too much vang bend (as denoted by the overbend wrinkle extending all the way to the end of the boom), but this is a pretty big crew, are hiked hard, and beat us that day, so who knows.

vang4

Team Parramore upwind – note bent boom and overbend wrinkles.  Looks about right, but possibly still overpowered?

vang5

Team Michos (dark hull, far left) flat, fast, vang down and pointing.  Two boats in foreground need more vang (lots!) and more Cunningham in order to emulate the Michos. 

vang6

Good – the boat is nice and flat.  Heavy twist in main, however, is a product of too little vang

vang7

Team Michos with a good looking set up – vang is bending boom, overbend wrinkles 1/3 to ½ toward the clew, Cunningham and outhaul nicely set.  Note difference in the twist to 1145 above.

vang8

Team Parramore looking good. 

vang9

In a lull and coming out of the leeward mark, Schwenk and Michos with vangs eased somewhat, but overall set up very consistent.  We (1137) are blocked back to straighten the mast probably at least an inch from the front deck.  Team Michos (217) appear to have their mast even straighter – in both instances this is so that when the vang and mainsheet are on hard the boom will bend without making the mast bend to the point that the overbend wrinkles extend too far toward the end of the boom. 

vang10

In this team’s defense, this is a borrowed boat, but it’s definitely time to ease the main and pull on some vang.  Lots of vang!

vang11

Note the difference in vang here – but they arrived at the same spot on the race course.  I’d go with a little more and a little less.

vang12

Vang eased for the mark rounding.  This prevents breaking the boom, and also makes it easier to turn the boat to leeward. 

vang13

Vang off correctly off on the rounding!

vang14

Better blow that vang!

vang15

Gybe set around the windward mark.  Parramore (646) in a good reaching position, with vang about right – reset since the mark rounding.  The boat behind appears to have no vang, and is probably sacrificing power. 

vang16

OK – definitely sacrificing power.  (And slide back to get the bow up!). 

vang17

It is no accident that all of these boats have the same amount of vang

Final thoughts:

In light air, the vang will choke off the main, and is definitely slow.  In breeze, however, it is not possible to seriously compete without a fair amount of vang, and a fair amount of adjustment to the vang.  Good crews are adjusting before and after every mark and with many changes in conditions upwind.  Downwind after the mark the vang is typically set and left, unless there is a reaching/running situation.  Reaches typically require more vang.  Down wind, the leach of the main should not be flopping around – top batten should be parallel to the boom. 

Good luck and always feel free to ask questions!

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