J/Boats J/111, Owner'S Manual

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J/111 OWNER MANUAL 16
Tuning the Rig
Tuning the Mast
Following is a general guide to tuning your J/111 mast. Please consult your sailmaker for “fine-tuning” the mast
to match the sails.
BEFORE YOU BEGIN INSURE THE TWO MAST TIE-RODS ARE PROPERLY INSTALLED BETWEEN THE
MAST AND THE UNDERSIDE OF THE DECK AND THE PRE-MOLDED SPARTITE MAST WEDGE IS IN
PLACE AT THE MAST COLLAR.
With the standard length J/111 headstay (turnbuckle ½ open) and the mast step situated in the middle, the mast
rake as measured from the back of the mast at deck level to a plumb on the main halyard should be
approximately 20-21 inches.
The upper (V1) shrouds are attached to the aft chainplate hole. The lowers (D1s) are connected to the hole on
the portion of the chainplate that angles inboard. The intermediates (D2s) are secured at the outboard end of
each lower spreader.
Begin by hand tightening the V1 shrouds, being careful to keep the mast centered aloft. Check alignment by
hoisting a tape measure up the main halyard and comparing measurements to the port and starboard
chainplates. When the top of the mast is centered, sight up the mast track to check for alignment of the lower
part of the mast. Adjust the shrouds as necessary to center the mast.
After the rig is centered and hand tight, we recommend additionally tightening the shrouds. Here is a good all-
purpose setting based on the initial J/111 sea trials for tuning, as measured with a Loos Gauge for Rod Rigging.
Shroud Rod Dia Load % breaking Loos Gauge #
V1 -10 0.250” 1850 lb 18% 68
D1 -8 0.225” 850 lb 10% 33
Typically the D2’s should remain loose until the V1s and D1s are close to their intended tensions. Thereafter
the D2’s can be taken up to hand tight and adjusted after going sailing and checking the mast on both tacks for
straightness.
You’ll find it easiest to tighten the V1 shrouds if you pump the backstay down first to bend the mast and thereby
reduce load. Under sail, it is easiest to adjust the leeward shrouds, then tack to adjust the other side. The
Ronstan Calibrated shroud turnbuckles are best adjusted with large crescent wrench. It is also a good idea to
use grease on the threads of the turnbuckles to help reduce friction as the loads increase.
Once you have initially tuned your J/111, go sailing in a brisk breeze, spending equal time on both tacks. Even
though rod rigging is a very low stretch material, you’ll still see a little loosening after the initial breaking in period.
Be sure to sight up the mast while it is under load to confirm that the mast remains in column. Make the
appropriate adjustments as necessary.
A note about the standard Dyneema backstay. You will find that a brand new backstay will appear too short.
This is normal and is a result of the cover of the backstay bunching up while coiled. A short length of Spectron
attached to the backstay hydraulic cylinder and the backstay and a few hours of tension should allow the
backstay to properly stretch to its intended length. Also, while reaching and running you may notice a vibration
sound that can take place due to the large diameter of the backstay and whatever harmonics develop. This
typically only happens in breeze about 15 knots and is considered normal.