IMPROVEMENTS IN TUBULAR MASTS AND SPARS, AND IN CRUTCHES FOR SUSPENDING SHIPS' YARDS
Year: 1864

page_text: PROVISIONAL SPECIFICATION left by Thomas Moore at the Office
of the Commissioners of Patents, with his Petition, on the 29th
July 1864.
I, THOMAS MOORE, of 45, Eastcheap, in the City of London, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN TUBULAR
MASTS AND SPARS, AND IN CRUTCHES FOR SUSPENDING SHIPS' YARDS," to bo
as follows:-
I seek by this Invention to give increased strength to the masts, yards, and
booms of ships, to diminish the weight aloft, and to afford the means of reefing
and furling square sails by the employment of one yard only, when the sails
are rolled entire."
To carry out these objects I propose to build masts, yards, and booms with
hollow cores. The hollow tubes may be made of wrought metal, either drawn
or cast, instead of making them of iron plates formed as cylinders, as at
present. Instead of metal, the yards or booms may have wooden tubes in
the centre strengthened with flat bar iron, or the interior may be fashioned
cylindrically with hooped bar iron and then built over with wood. To ven-
tilate the ship's hold or between decks the tubes of the masts may have
apertures for the admission of air. The tubes for masts, booms, or yards,
to be covered or built over externally with wood according to the strength
required. The wooden sheathing I propose to let on in pieces, and I prefer
securing them with waterproof marine glue or a suitable adhesive compound,
the whole to be fastened with hoops and painted or varnished. Should it be
necessary to construct the lower masts for cutting away, I should make the

page_text: metal tubes so that two sections meet above the upper deck. Round this
joint I place a broad and strong keyed and pinned metal hoop over the built-
up wooden sheathing, which hoop may serve to carry belaying pins.
The next part of my Invention relates to supporting a yard when hoisted,
and to allow the yard to revolve and roll up a sail round it as the yard
descends. I affix to a sliding hoop on the mast a swivelled neck next towards
the fore part to support a crutch. The topsail tie will be shackled to a ring
or eylet; the stem or shaft of this ring or eylet will enter a slot on the neck
of the parral hoop and then be loosely bolted to allow it to work. The
bottom of the shaft will carry a crutch balanced to rise when there is a strain
on the halyards and fall by its own weight; this crutch may be kept back by
a clutch or bolt. When the yard is mastheaded and the halyards hauled
taut the crutch comes up to the yard and helps to sustain the yard by its
resting therein. When the balyards are let go and the yard is held by the
lifts or the revolving power on the yard arms, the slackness of the tie causes
the crutch to fall and clear itself from the yard and sail. I also apply a
double-friction swivelled roller to an arm on the ring which supports the lifts,
which friction rollers has formed the subject of a former Patent granted to
me, No. 1069 of 1863.
The last part of my Invention relates to the supporting, rigging, and
running in and out of studding-sail booms. I run these in and out of the
hollow tubes in the yards. To the foot of the boom I attach by a ring,
sheave, pin, or any other suitable method, a line or chain, which is. then
passed through a sheave or pulley on the neck of the lift hoop and the leading
end carried below or made fast aloft. As this rope or chain would run in
with the boom by hauling on it, the boom would run out.
run in again by a line fast at the outer end. I retain the
The boom can be
boom in the yard
by a cap screwed on to the end of the yard after the boom is let in, or such
cap may be let on in the same way that a bayonet is fixed to the end of a
musket.