Masthead rig with one set of in-line spreaders, deck-stepped mast, forward and aft lower shrouds

(Masthead rig with one set of swept spreaders and forward and aft lower shrouds, is tuned with the same method)
Cap shroud15% At the crane • Read the “At the crane” section on pages 20-21. • Lift the mast and place it on the T-base. • Attach the cap shrouds, backstay and forestay. • Tighten the cap shrouds, forestay and backstay hand-tight so that the mast is stayed both laterally and longitudinally. • Lower the lifting strop and attach the lower shrouds. Hand-tighten and move the yacht away from the crane.
Backstay 15% Tuning • Check the mast rake. If necessary, adjust using toggles on the forestay.• Tension the cap shrouds to 15% of the breaking load of the wire. See the “folding rule method”, page 29. • Straighten the mast using the forward lower shrouds. If necessary, adjust the rigging screws for the cap shrouds without changing the cap shrouds tension (slacken one rigging screw by exactly the same amount as you tighten the other one). Check that the mast is straight by sighting up the luff groove, all the way up from deck level. • 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 pre-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
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