It must have jammed inside near the masthead during construction and suddenly Iqosened with the vibration.
Another method of stiffening up a metal mast was to fit internal angle bars for the full length, and doubling plates at deck level, but nevertheless when made in ill-equipped shipyards such masts frequently failed. The smithwork, such as capbands and trusses, also varied from being neat and well formed to crudely fabricated pieces hammer-welded together , which logbooks frequently reported as giving way.

  In general appearance, the single tree wooden mast and the iron mast had a taper from the deck to the hounds, and built masts had very slight taper, if any at all.

  Topmasts with a few exceptions were more commonly of wood, and topgallants which also incorporated royal masts were of wood, tapering down in the round to the truck. The transition from the topgallant to royal mast was made with a very slight shoulder which stepped down in diameter, over which a thick rope grommet was placed, this serving as a stopper for the rigging (stays, etc.) to prevent it sliding down the mast.

  Another way was to fit a copper cylinder or funnel above the shoulder with a slight projecting flange on its lower rim. The spliced eyes of the backstays, the topgallant shrouds' seized eyes, and fore and aft stays were all fitted snugly on this funnel. Its.purpose was to retain all this rigging in place whenever the topgallant mast was lowered down, so that when the shoulder position passed through the cap band all the stays, etc. hung slack from the funnel, which would then be resting on the cap. On raising the mast again, the funnel would catch on the step and hoist to its original position with the rigging taut again.

  The reason for lowering the topgallant masts was that tea clippers in dock with a minimum of ballast were very often temporarily unstable, and on a number of occasions actually heeled over onto dockside sheds, as did the Cutty Sark once in London. Therefore as much top weight as possible was lowered when a clipper ship was in dock with an empty hold.

  The jib-boom was also usually withdrawn on entering dock, but this was to prevent it fouling other ships, or poking into someone's bedroom in adjacent terraced houses.
The peaks of the masts on British ships were crowned with flat wooden trucks, like flattened buns, which contained two small sheaves for flag halliards. American trucks were distinguished by a spherical ball, usually gilded. The tallest mast would or should have had a lightning conductor also.

  Wooden yards were made out of single trees, except some of the largest lower yards in American ships, which were made of two pieces spliced or fished together with coaks, as for the mast, and bound with iron hoops.