Patent granted to Samuel Brooking, of Plymouth, Admiral of the Royal Navy, for a new Method of making Sails of Ships and other Vessels.—Dated September 4, 1828.

In the common method of making square sails for ships, the seams of the canvas are arranged so that they shall lie vertically, when these are set up in their places; but in Admiral Brooking's sails the seams are placed parallel to diagonal lines drawn from their lower angles to the upper opposite angles, as far as a vertical line through their centres that divides them into two equal portions, and hence from this latter line the seams shape downwards and outwards in opposite directions at each side.

As the strain at the junction of the several pieces of canvas at this central line will be considerably greater than in other parts of the sails, these pieces are to be made to overlap more here, and to have more courses of sewing than elsewhere.

The seams of the triangular sails, such as jibs, foresails, and stay-sails, are, in this new method, to be formed parallel to a line drawn from the lower outward angle of each to the centre of its side next the stay, by which it is to be sustained.

The advantages stated by the admiral of this mode of construction are, first, that sails having been found to be much more liable to tear in the direction of the seams than across the breadths of canvas, by placing the pieces in the direction above mentioned, in which he states the greatest Strain lies, the sails will last considerably longer, and be less liable to accidents; and, secondly, that sails thus made, by bagging less than the common sort, will present a more even plane to the action of the wind, and thereby enable vessels, in which they are employed, to sail faster in similar circumstances.

Obs.—Admiral Brooking is not the first naval officer to whom the advantage of altering the direction of the seams of sails has occurred; since, in June, 1805, Captain Malcolm Cowan, of the Royal Navy, obtained a patent for this purpose (which also includes a great and much-approved improvement in reefing sails): the specification of this is inserted in our 9th vol., second series, p. 88; and in our 13th vol., same series, p. 253, will be found ample testimonies of the great benefit derived from both those improvements.

Captain Cowan directs that the lines of the seams of square sails shall be parallel to the yards, and those of triangular sails in a similar position, which we imagine to be a more effectual arrangement for the purpose than that proposed by the admiral, particularly with regard to the former; since, it appears to us, that in square sails, when sailing on a wind, or obliquely to its course, the strain on all the pieces of canvas at the leeward half of the sail will be still more precisely at right angles to the direction of the seams than in the common method, supposing the admiral's own assertion to be correct, that the direction of the strain is from the clue, or lower angle of the sail, to the opposite extremity of the yard to which it is appended, obliquely across its substance; so that while the windward half of the sail will be rendered stronger by the new arrangement, the other half will be weaker than in the old method, from which defect Captain Cowan's plan is entirely exempt.

We also think that the prevention of the sails from bagging (if the admiral's method of forming them would have that effect, which we somewhat doubt,) would be rather injurious than serviceable to the velocity of a vessel, as it has frequently been ascertained by accurate experiments, that a concave, or hollow surface, makes more resistance to the wind than a plane of the same transverse dimensions, of which a remarkable instance may be seen in our 10th vol., first series, p. 93, in the account of experiments on the resistance of air by the late Mr. L. Edgeworth.

The Repertory of Patent Inventions: And Other Discoveries and Improvements, Volume VIII, London, 1830. pp 536-538.

Transcribed by Lars Bruzelius.

The Maritime History Virtual Archives | Rigging | Search.

Copyright © 2009 Lars Bruzelius.