Tartan 4100, Owner'S Manual, Page: 23 / 54

T4100 OM rev2
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point on the other side of the deck. With the same amount of downward tension, you will be able to just
touch the shackle to the reference point if the mast is plumb transversely. If not, let off one upper shroud
turnbuckle and take up on the other in order to bring the masthead closer to center line until the halyard
shackle touches both reference points under the same downward tension.
The particular part of the rail or deck you choose as your reference point is not important as long as it is
the same point on each side. Once the mast is centered transversely, tighten both upper shroud
turnbuckles uniformly, one full turn one side, then one full turn on the other. Repeat until the turnbuckles
become difficult to turn. Pin the turnbuckles.
Tighten the lower shroud turnbuckles so that almost all of the slack is removed; the center point of each
lower shroud should have about 1 inch of play in either direction. Sight up the aft side of the mast to
make sure that it is straight. The lower shrouds may require adjustment to straighten the mast.
Now check the rake. Rake is the fore and aft angle of the spar. The Tartan 4100 spar is designed to carry
up to (approx.)
12 inches of rake . Rake effects the position of the center of effort of your sail plan and,
consequently, the balance of the helm. The effects are more pronounced in heavier winds. The extent of
rake on our boat should be determined by your particular sailing characteristics, the typical local wind
conditions and your sailmaker's suggestions.
Forward rake should be avoided. The main halyard may be used to measure rake. In calm wind and sea,
with the boat floating level on her lines, hang a plumb weight or equivalent, such as a hammer or wrench,
from the main halyard. Adjust the halyard so that the weight is suspended just above the gooseneck. The
fore and aft distance between the mast and the halyard at the gooseneck level is the amount of rake. Ease
off the forestay turnbuckles and tighten the backstay turnbuckle (or vice versa) until the desired rake is
achieved. Pin both fore and backstay turnbuckles.
Unless the rake has to be re-adjusted in the future to correct helm balance, these turnbuckles will need no
more adjusting. Additional tension may be applied by the backstay adjuster.
Check that the outboard ends of the spreaders are padded and taped to avoid chafing the genoa.
Ensure that all turnbuckles are pinned. The mast should be fixed at the step to prevent fore and aft
movement and to hold the mast in the step.
You are now ready to complete the tuning procedure while sailing.
4.4
Tuning While Sailing
Select a day with a steady 8 to 12 knot breeze and reasonably flat sea. Put the boat on starboard tack,
close hauled. Sight up the luff groove of the mast. If the mast seems to fall off to leeward at the
spreaders, luff up slightly and tighten the starboard lower shroud as necessary. Put the boat back on the
wind and check the spar again, adjusting as necessary. When the mast appears straight, bring the boat
about and do the same on the port side.
Check the following carefully:
When the upper shrouds are at optimum tension and when at about 15 to 20 degrees of heel, the leeward
rigging should look slack. This is quite appropriate and should never be tightened. When close hauled
under genoa and main, the forestay may appear quite sagged. Tensioning the backstay will reduce the
amount of sag, but the sag itself can never be eliminated. As a rule of thumb, the maximum static
backstay pressure should never exceed one quarter of the backstay breaking strength.
If your boat is brand new, the rigging may seat and stretch to the extent that tuning from scratch again
will become necessary in a matter of weeks. However, after this initial working-in period, you will find