Todd,
You haven't said if this is a new boat or a new to you boat. What year is the boat? Is there any reason to suspect the mast tabernacle and conpression post have sunk? It is also possible to tighten the fore and back stays too tight, introducing excessive bend in the mast. This could cause your shrouds to loosen. How hard was it to raise the mast and connect the forestay? I take it, she was already rigged when you took ownership of her?! How old is the standing rigging? Maybe it is time to replace them? What happens when you let them loose? Do they kink or roll up?
To tune:
In the water so you are working with level waterline, hang a weight on you're halyard just above the turnbuckle. Measure your rake by the distance the halyard hangs from the mast just above the gooseneck. Different sailors like different rake. Start with 4" out from your mast. You can control this with the forestay.
Do your shrouds tighten now that there is minimal pressure on the mast? Tighten your lower shrouds to center your mast until tension feels tight when you pluck it. If the mast is plumb, tension will be equal. Next, tighten the upper shrouds. Make sure you keep the mast straight and plumb. The weighted halyard will be your guide.
Once you have everything tight, take her for a sail. Watch the lee shrouds on a beam reach in a strong wind (15-20) knots. If they visibly lose tension (the turnbuckle falls out of line with the shroud) take up the slack evenly on both sides.
I recently learned that current thinking is your shrouds should never go slack, but I've always sailed with the idea that a little slack above 20 knots on a beam reach is fine, if not ideal.
The cut of your main can give you a good idea if you have the rake right. Normally, the boom will be level shitting slack with the sail raised.
-Will (Dragonfly)
