This is a solid
hard vang. It has a big adjusting wheel and a lot of threads but it really
has a small range of settings. As you try to increase twist (loosen the
leech) the counterclockwise turning of the adjusting knot lengthens the vang
driving the boom up. Because the mount to the boom is fixed, this
lengthening pulls the mast toward the aft creating a convex curve in the
mast centered on the boom gooseneck. Whew! We have no alternate adjustment
for this. You can help. Design a vang that will re-reference; like a shock
spring in the tubing. Good! The world will beat a path to your door.
you tighten and hence, shorten the vang, the mast will bulge forward.
Generally, this is only for high wind tuning and all the effects are
You have set
the boom close to centerline and the winch is fully close hauled. It is
expected there will be little to no twist in the main in a calm room.
Understand, as you lengthen the vang to introduce some twist, the boom rises
and thereby, increases tension of the sheetline. This will defeat your
effort. Think about it. So, as you go through the process of setting twist
and/or re-referencing the vang, always reset the sheetline.
Roll the boat
over in the cradle. Set the vang so that you will have zero twist. The top
batten of the sail will be parallel with the boom (not centerline). Now, if
the mast is still straight and you let the sails out one bump on the TX
stick, you will see the batten move away from parallel slightly. Good. If
this happened for you, then this is the base setting. These angles will be
greater in the water under some wind pressure.
twist till you have about 15 degrees off the boom at the top batten and one
bump out. Is the mast bend starting to convex? What does that mean? The vang
is too long and is pulling the mast. Right! If this is the case you want to
re-reference the vang mount to the boom. Without changing the setting of the
vang, move the mount forward toward the mast. You have two holes in the
mount and boom. Move the aft screw to the forward hole. Drill another
forward hole through the empty mount hole with a #50 bit. You can do this on
the floor with the boom sheeted out.
How is the mast
bend now? That should have relieved some or all of it. Did you reset
the sheetline and are you one bump out? You getting the idea of
re-referencing? Okay, the reverse will be true of a forward bow in the mast.
Check the BST is still at 2 pounds. To a lesser degree than the sheetline,
the BST is effected by the vang.
What you will
notice is that there is a point in the vang connection that the adjusting
wheel feels free and not harder to turn one way or the other. That is a
neutral spot that will give you the range needed.
You just got 2
years of experience, all that we have and with over a dozen rigs built.
There are a lot of words here but the procedure of setting the vang, if it
is off, is simple and far easier for a two-handed person. Vern went to sleep
at 19 above. Its okay, we are used to that.
Why twist? Lets
don't get into it now...