It is best to get your rigging tension specifications from the yacht manufacturer and to use a tension gauge to ensure they are correct. However if this is not possible you may like to proceed as follows.

The rigging tension has an important influence on both the durability and performance of the system. Contrary to popular thought a slack rig is more punishing to the cables, fittings, and hull than a properly adjusted tight rig, since it can subject the entire system to excessive movement and can cause misalignment, wear, shock loading, and fatigue. Similarly, the sailing performance is affected since the rigging tension determines the shape and deflection of the mast and the sag of the forestay. The expert skipper will benefit by maintaining consistent rigging tension while developing the optimum sail shape and sailing tactics.

Masthead Rig        Fractional Rig