The object of tuning the rig is to get a tight forestay when going to weather and to get the mast straight while underway.
1. Mast alignment vertically-Athwartships (sideways).
a. Locate the port and starboard pad eyes near the rail, aft or the lower shrouds.
b. Measure the distance from the bowplate to each pad eye to insure they are equidistant.
c. Remove all turnbuckle cotter keys.
d. Loosen (very slack) the backstay and all four lower shrouds.
e. Shackle a small block to the port pad eye.
f. Tie a small line to the topping lift and lead It through the block and to a small fish scale. When measuring always apply ten pounds of pull on the line. This insures constant stretch in the topping lift wire and the required accuracy.
g. Apply ten pounds or pull an the port side assembly and mark the line attached to the topping lift with a felt tip pan. It's convienient to mark the line opposite the pin In the block.
h. Move the block/shackle/fish scale assembly to starboard pad eye and repeat. If pen marks are at the same point (relative to the block pin) on both port and starboard aides, the top of the mast Is centered on the mid line of the boat. Athwartships adjustment Is complete.
i. If not, adjust upper shroud turnbuckles until pen marks are at the same point on both port and starboard pad eyes. When adjusting, loosen one side 4-8 half turns then tighten the other side 4-8 half turns, and so on.
j. Upper shrouds should be left quite tight
2. Jumper Strut Adjustment.
a. Go up the mast to the jumper struts and remove tape from adjusting nuts on both jumpers (some Tritons have a turbuckle system).
b. Rotate the nuts clockwise to extend the threaded shafts. This Increases the tension in jumper cables. Do this first a few turns on port, then a few turns on the starboard, etc.
c. Increase the tension until the mast section above the spreaders bows forward approximately 4 Inches without a persons weight on the mast Use your eye to estimate this distance by looking up the mast from a standing position on deck.
d. Check mast from a forward position as well (looking aft from the bow). It Is possible to put a side twist in the strut assembly If unequally tensioned.
3. Removing mast bends
a. To remove bend #1 (above the spreaders), tighten the backstay until the top of the mast is In-line with the base. The mast will now bow forward In the middle (bend "2). Remember, all four lowers are still slack.
b. Remove bend #2 by tightening the rear lower shrouds equally until the mast is straight.
c. Forward lower shrouds should be tightened only to remove the slack.
4. Testing under sail, (A 10-12 knot breeze is best.)
a. Don't reinstall cotter keys until alter sea trials.
b. Sail to weather.
c. Check plumb athwartships by sighting up mast from deck. Adjust lowers to remove athwartships bow In the middle of the mast Adjust upper shrouds to remove any falling-off of the mast above the spreaders.
d. Check on both tacks.
e. Reinstall cotter keys and tape over.
f. Mark backstay with a file to proper tensioning point. Loosen backstay when not sailing to ease loading on rig.
g. Jumpers may stretch and may require periodic readjustment
- by Leigh Abell -