BASIC RIG-TUNING
This may be a bit redundant, as you’ve already read some good advice from previous posters.Stainless steel does not like to be under constantly changing tensile loads, so one objective of rig-tuning is to maintain a degree of tightness that doesn't allow this to happen. Most rig failures come from too light tension over a long period of time which causes fatigue in the wire and its connections (turnbuckles, chainplates, etc). Race boats use flexible rigs with backstay adjusters and other strategies to modify the rig underway, changing mast bend and sail shape. Good stuff for the racer, but not appropriate for the lone cruising boat. The prime objective for the cruising rig is to fix the mast in position and keep it there under all conditions.Many people have their boat yard tune the rig when the boat is launched. They then sail off for the season with no further concern for the rig. Actually, the rig will change during the first few weeks after launch. The boat assumes its in-the-water shape which may be somewhat different than its on-the-hard shape. The rig will subsequently change and further tuning should be done. There are three basic rules of thumb:1. Opposing shrouds must have the same tension.2. Tension order - The forestay must have the most tension (see notes below). The upper shrouds come next, then the lower forward shrouds, and finally the lower aft shrouds and the backstay.3. Tension the shrouds so that, when heeled to about 15 deg you can almost feel some looseness (to lee)... but you can't see it ... It's "snug", but not as tight. This is done at sea obviously, and something that should be regularly observed.Notes:1. Getting proper forestay tension may be just guesswork if you have roller furling.2. Tensioning the forward lowers slightly more than the aft lowers should produce a slight pre-bend in the mast when the backstay is tensioned. You'll see it if you sight up the mainsail track. It should be barely noticeable. This pre-bend just tells the mast in what direction to bend when loaded. It stops fore and aft "pumping" of the mast that can cause metal fatigue.3. Although some sailors agonize about mast rake, in my opinion, most rigs are not particularly rake sensitive. Mast rake should not be confused with mast bend. Mast rake is how much your mast leans aft towards the transom. The amount of mast rake you might chose depends on the conditions you sail in. If winds are mostly light then a small amount of mast rake might be preferred. If, however, the wind tends to be stronger most of the time slightly more mast rake be beneficial. The easiest method to measure Mast rake is to hang a Plum Bob on the main Halyard, preferably on a windless day.HTHGord