Practical Junk Rig: Design Aerodynamics & Handling
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This encyclopedic volume synthesizes 25 years of research and development of this unique rig as adapted to Western craft. It is a work that has been welcomed by the growing number of yachtsmen and designers throughout the world who already enjoy the benefits of the junk rig or who wish to do so. Practical Junk Rig examines the design and aerodynamic theory behind junk rigs and discusses how best to sail them. It outlines the rig in detail, the principles that underlie it, considers possible alternative shapes and arrangements and analyzes performance, all assisted by a wealth of detailed line illustrations.
off at right angles to the boat is a considerable bonus. Conventional spinnakers are not efficient for their area; they are just an efficient way of setting a lot more area. There is no standard type of sail in China, and every conceivable variation seems to exist. Fig. 1.1 shows some of the sail shapes recorded there in the past fifty years. The square-headed sail a seems to be the ancient shape and is still widely used, particularly on inland waters in the high-aspect-ratio form shown at b. The
the same direction as the plane of the sail, the yard can pitch bodily to and fro over quite a wide arc as shown by dotted lines, limited ultimately only by the 54 Practical Junk Rig batten parrel (A) of the top batten. This pitching may cause alternate ends of the lowest operative batten to lift up from the furled bundle, as shown. On the backswing it is possible for the throat to get the wrong side of the mast or the mast lift, although with the recommended form of sail (Fig. 2.28) this is
arise from trimming sheets and from reefing. If the span shown in Fig. 4.13 were to be used at a very steep angle, the thimble would jam against the block and the lower Fig. 4.15 The Sheets 61 parts of the span would go slack unless the lengths of the two spans were readjusted, whereas the arrangement shown in Fig. 4.15 will tolerate the full range of sheeting angles without any readjustment. At flat sheeting angles its lower parts form a long V with minimum pinching effect, whereas the V of
likely to be used in the West, but anyone wishing to use four or more masts could extend the nomenclature for himself. So far the majority of Western rigs have been single-masted, and most of the rest have been two-masted schooners with the mainsail about twice the size of the foresail. The considerations that affect the choice of rig are discussed on p 94. The junk sail may be described as a fully-battened balanced lugsail. Fig. 1.4 shows its essential features and the names of its parts. The
should carry away. The sail would then be reefed by passing a lacing, or individual stops, round the furled sail-bundle and through these grommets. The emergency lacing grommets (E) in Fig. 11.2 are for use only if the roping of the sail should start to pull out of the track on the yard or boom. It is suggested that the luff and leech should be lightly Sheet windows for double sheets 168 Practical Junk Rig Fig. 11.6 Sail of more than 300 sq ft (28 m2) The Sail 169 Fig. 11.7 Detail for