IMPROVEMENTS IN SHIPS' SAILS
Year: 1861

page_text: PROVISIONAL SPECIFICATION left by William Clark at the Office of
the Commissioners of Patents, with his Petition, on the 23rd January
1861. A communication from abroad by Mr. Justin Louis Hyppolyte
Eugène Bonnet, of 29, Boulevart St. Martin, Paris, Merchant Captain.
I, WILLIAM CLARK, of 53, Chancery Lane, in the County of Middlesex,
Engineer & Patent Agent, do hereby declare the nature of the said Inven-
tion for "IMPROVEMENTS IN SHIPS' SAILS," to be as follows:-
All sail cloths, with the exception of those made of American cotton, become
lengthened and stretch by use, hence it results that in making a sail it is
necessary either to make it too small at first, so that by use it shall attain the
required size, or to cut it smaller after it has become stretched, when owing to
its slackness it is impossible to set it properly. When cutting sails smaller
the bolt ropes generally have to be unsewn, and the cloth then cut to the
shape required, the folds and bolt ropes being replaced as before, which
requires much labor, and causes loss of cloth, as the cuttings are of no use
whatever.
In making sails according to this Invention, I unite the widths of cloth in
regular or irregular quadrilateral figures according to the part of the sail to be
formed, and I cut these quadrilateral figures into triangular pieces, or it may
be into triangular & irregular four-sided figures, according to the position they
are to occupy in the sail, which is effected without any waste of material, the
triangular pieces being disposed with their angles converging to the point of
strain or traction, and the several pieces when combined making up the area
of the sail. The seains formed by the junctions of the angular pieces converge

page_text: more or less (in square sails) towards the middle of the sail. Between the
angular pieces I dispose parallelograms composed of widths of cloth, which in
square sails converge towards the middle, one from each of the lower corners,
and a third centrally from the top to the same point. As the sail stretches
these pieces can be readily removed in part or altogether, and simply
cutting and splicing the binding ropes. I round the corners of square sails
for this reason, that when a sail is set and receives the impulse of the wind,
the bolt ropes of the sides and borders are drawn towards the centre, hence
it results that the surface between the bolt ropes is diminished, and forms a
segment of a circle, of which the centre is outside the sail; the latter thus
becomes inflated, which renders its power defective when close hauled. The
same method applies to forming mizen sails and jibs, but I make all the most
acute angles of the pieces converge to an angle of the sail, and from which
angle across the middle of the sail I introduce the parallel removable widths
of cloth. In these cases I compose the sail entirely of angular pieces, pro-
duced as aforesaid, with the addition of the parallel reducing pieces. These
reducing pieces when removed are available pieces of canvas, whereas when
a sail is reduced, as in ordinary, it results in useless cuttings, besides entailing
great labor. By the improved arrangement of the canvas the several breadths
converge towards the point of traction, so that the strain is always in the
direction of its length, and not across the seams, and, therefore, resulting in
greater strength. I carry the bolt ropes round, and afterwards attach the eyes
or thimbles by separate strops to the sail, which prevents liability to rupture
when the strain comes on the points of attachment, which system is applicable
to all kinds of sails. The removal of the angles of the sails also allows of
establishing on the same spar sails which would otherwise be too large.