But the sail was intact without a split in the middle; also it could be furled completely on the yard by continued rotation.

  Both these inventions were advantageous in that the reefing operation could be carried out from the deck by about two men, thus reducing the crew complement. They were in vogue for a short time, however, on clipper ships, being used latterly on the mizzen topsail only. Smaller vessels such as topsail schooners or brigs could be found with them well into the 20th century.

  In the late 1860s the larger clippers fitted double topsails, but single topsails were more common.

  The introduction of the double topsail also brought about a change in the shape of the tops on the lower mastheads, which the detail illustration explains (36). Originally tops with single topsails were very wide, about half the beam in warships to accommodate fighting men, less in merchant ships. They were either semicircular on the front rim or squarish, with the topmast shrouds attached to straight sides which gave them a good spread. There were two crosstrees to support the width, one on the aft side of the lower masthead and the other on the fore side of topmast heel, with along narrow lubber's hole between. The wide spread of the foremost topmast shroud meant that when the topsail yard was braced at an angle, especiall y at half hoist in the reefed position, it would touch and chafe this shroud.

  By rounding the top into a semicircle to its after rim, this shroud was brought closer to the mast and thus allowed the yard to be braced without so much chafe. The forward crosstree now being so much shorter was moved between the two mast portions for better support of the top, and the long lubber hole was divided into two parts. Most American whalers and some packet ships in the first half of the century did not move this trestle tree, however, but compensated by strengthening the forward curved rim, a style that can be seen today in the whaler Charles Morgan (1841) at Mystic, Connecticut. However, once the double topsail was established with its lower yard always at a lower level, the foremost topmast shroud had to be brought in closer still, and this was achieved by making the top more triangular in shape with a rounded front, and on wooden tops usually with three crosstrees.

  The advent of the metal lower mast brought about a metal rimmed top with plate cheek supports and no crosstrees. It was shorter in the fore and aft length and the sides were more angulated and on a gradual curve around the front rim in a pattern continued up to modern times.

 The change in arrangement of the crosstrees followed somewhat the same principle as did the tops.