AN IMPROVEMENT IN THE RIG OF SHIPS OR VESSELS
Year: 1859

page_text: PROVISIONAL SPECIFICATION left by Henry Duncan Preston Cunning-
ham at the Office of the Commissioners of Patents, with his Petition,
on the 27th January 1859.
I, HENRY DUNCAN PRESTON CUNNINGHAM, of Bury, near Gosport, in the
County of Hants, Esquire, do hereby declare the nature of the said Invention
for "AN IMPROVEMENT IN THE RIG OF SHIPS OR VESSELS," to be as follows:-
My Invention consists of an improvement in the rig of ships or vessels,
which may be called the double-gaff rig, and which is more particularly
applicable to ships furnished with propelling machinery, and which have
frequently to proceed against the wind, when it is desirable to reduce as much
as possible the resistance of the wind aloft on the rigging, and also that the
sails shall be of such description that the ship shall sail as near the wind
as possible. With this view, and other considerations connected with the
improvement of the rig of ships and vessels, I have invented an arrangement
of sails which are efficient when the ship is on a wind or close hauled, and
which will enable a ship to lie nearer the wind than can be done with what is
called square sails, an arrangement which provides for the spread of a larger
area of canvas when off or before the wind than can be done by ordinary
fore and aft sails, and which sails, when taken in for the purpose of the ships
being propelled against the wind, do not present so much resistance to the
ship's progress as yards do in square-rigged ships. To carry this into effect,
I use a system of double-gaff or other fore-and-aft sails, that is, instead of, in
the case of main or fore trysail of a schooner, one gaff, and one sail being

page_text: on the mast, I use two, one alongside of the other, each gaff or sail being
independent of the other, and working on its own points of suspension. The
same principle or arrangement can be carried aloft to upper sails, and so a
system of these double sails arranged. Now, I contemplate, that when the
ship is "on a wind" or close hauled, one only of these double sails will be
used as an ordinary fore-and-aft sail, that when the ship is off or before the
wind both the sails will be set, one on one side, and the other on the other
side, thus a large area of canvas will be spread, and those requirements
provided for which are now rendered by the use of square sails set on yards
aloft, &c. Again, when it is required to propel the ship against the wind,
the gaffs on which the double sails are spread come fore and aft, and so do
not impede the ship's progress so much as the yards on the ordinary plan;
thus, I contemplate that I obtain the advantages of the square rig for running
before or off the wind with those of the fore and aft rig with reference to the
ship's lying near the wind, and offering little resistance aloft to the ship's
-progress when being propelled against the wind. In the details of carrying out
this arrangement of sails, double trysail masts may be used, so that each sail
shall have its own mast to work on; or, if the sails be fitted with brails, and
the gaffs kept aloft, that is, the sails taken in without lowering the gaff down,
there is no necessity for double trysail masts, but each gaff could be fitted on
its own axis at its end, the axial points being placed as far aft as possible to
allow the gaffs to go forward as far as possible, to facilitate the trimming- of
the sails; the heads of the sails may also be fitted to haul out and in on the
gaffs by hoops or metal travelling rods, or grooves both on the masts and
gaffs may be used.