The mast is made of white pine, the centre of it is bored out, for the lowest twenty feet about 12 inches diameter--the next 20 feet, 10 inches diameter--the next 20 feet, 8 inches, and the remainder 7 inches.

This was done to make the mast lighter, and, by the circulation of air, enable it to season itself.
The main boom is 95 feet long[F] and made like a cask.

The staves are 31 in number, of white pine, 2-1/4 inches thick; the staves are of different lengths, so as to vary the points at which they respectively abut.

The extreme length of boom is obtained by two lengths of the staves; small cogs of wood are let in at intervals, half in one stave and half in its neighbour, so as to keep them from drawing, the whole bound together with strong hoops fitted with screws.

The extreme diameter of the boom is 26 inches where the sheets are fixed, tapering off at the jaws, and 13 inches at the boom end.