Continued: Masthead, multi-spreader rig, in-line spreaders, deck-stepped mast, forward and aft lower shrouds. Alternatively, baby stay and aft lower shrouds. Tuning under sail • Sail the yacht and check that the cap shrouds do not begin to slacken until about a 20° angle of heel. • While sailing, check that the mast is straight laterally. Adjust this if necessary using the forward lower shrouds and intermediate shrouds. • Reef the sail and check the mast for lateral straightness. If the deviation from the straight line is greater than 5 mm, the lower shrouds or the intermediate shrouds must be adjusted. • While sailing, check the longitudinal trim of the mast. The mast must have a slight positive bend at the spreader area. Sight up the mast from deck level. Adjust if neces- sary by tuning the interplay between the aft- and forward • Give the mast a slight positive pre-bend using the inter-play between the forward and aft lower shrouds. The job of the aft lower shrouds is to reduce the bend to the amount originally determined. • Tension the backstay to 15% of the breaking load of the wire. Over a short period (a few hours) the load may be increased, but not to more than 30% of the breaking load of the wire. To achieve this loading, you will need a backstay tensioner. Make two marks on this so that you know when the normal (15%) and maximum (30%) loads have been reached. Use the “folding rule method” to find the correct setting. Since the backstay makes a wider angle with the mast, the forestay load will be about 40% of the breaking load of the wire when you put the “maximum load” on the backstay.
20° 40