Continued: Masthead, multi-spreader rig, swept spreaders, deck-stepped mast, forward and aft lower shrouds. Alternatively baby stay and aft lower shrouds. Tuning under sail • At about a 20° angle of heel and maximum pre-tension on the backstay, the lee cap shroud must not be slack. If it is, increase the pre-tension, but not to more than 25% of the breaking load of the wire (the same number of turns on the rigging screws as per your previous note).• Tune the mast straight laterally using the lower shrouds and the intermediate shrouds. • Reef the sail and check that the mast is straight laterally. If it deviates from the straight by more than 5 mm, the lower shrouds must be adjusted. • While sailing, check the mast’s fore-and-aft tuning. The mast should have a slight forward bend at the spreader area. Sight along the mast from deck level. Adjust if necessary using the lower shrouds. • Check the tune for different backstay tensions and different sail combinations (reef).
20° To ensure good fore-and-aft stability for this type of rig, it is very important that the leeward cap shroud is tight. This high level of pre-tension will generate plastic defor-mation on all grp hulls. As far as strength is concerned, the hull should be able to support these loads, but the deformation will make it necessary to check the tuning while sailing. This is particularly important when the yacht is new and at the start of every season.
38