Tartan 3400, Owner'S Manual, Page: 36 / 75

master OM Tartan 3400 2012.doc
Page 36 of 69
Tuning involves adjusting the tension in these shrouds and stays so that the mast will remain straight in
most sailing conditions with an appropriate amount of rake for comfortable helm balance. Tuning is
carried out in two phases - tuning at the dock and tuning while under sail.
4.3
Tuning at the Dock
All turnbuckles are equipped with toggles at their base, which eliminates bending load on the swage and
turnbuckle threads. Toggles are fitted to both ends of the forestay. As the boat tacks and the headsail
loading varies from side to side, the forestay terminals are subject to extreme fatigue loading.
Start tuning the spar by ensuring that the mast is in the center of the boat, perpendicular to the designed
transverse water line. Your boat may not sit level at the dock due to distribution of gear, stores and
tankage levels, so check the water line position both sides. Then slacken the lower shrouds completely by
undoing their turnbuckles. Take the main halyard and lead the shackle end to a point on the rail or
chainplate. Adjust the halyard so that the shackles just touch the reference point on the rail or chainplate
with a given downward tension, and then cleat the halyard. Then take the halyard to the same reference
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 3400 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.