A long round piece of timber, raised perpendicularly on the keel of a ship, upon which are attached the yards, the sails, and the rigging. A mast, according to its length, is either formed of one single piece, which is called a pole mast, or composed of several pieces joined together, each of which retains the name of mast separately. A lower mast being the lowest, is accordingly so called; the foot of it rests on a block of timber called the step, which is fixed on the keelson. A top mast is raised at the head or top of the lower mast, through a cap, and supported by trestle trees, (See the article Fid.) The top-gallant mast, is a smaller mast than the preceding, and is secured to its head in the same manner. The top-gallant royal mast is a yet smaller mast sometimes raised above the last mentioned; but in some ships it denotes a continuation of the topgallant mast, above the rigging: it is then called a pole top-gallant, to distinguish it from a stump top-gallant mast, which terminates just above the rigging. The main-mast is the largest mast in a ship, and stands nearly in the middle, between the stem and the stern.
The fore-mast is that which stands near the stem, and is next in size to the main-mast. The mizen-mast is the smallest mast, and stands about half way between the main mast and the stern. Made-mast is a term applied to a mast composed of several pieces of timber in contradistinction to those made of a single stick. Bough-mast, denotes a spar fit for making a mast. Besides the parts already mentioned, in the construction of masts, with respect to their length, the lower masts of the largest ships are always made of several pieces of timber firmly united, by stout iron hoops. As these are generally the most substantial parts of various tiers, a mast thus formed is esteemed stronger than one consisting of only a single timber, the strength of which, by internal defects, may be considerably impaired. Attempts were made some years ago to introduce hollow masts, the invention of Mr. George Smart, of Westminster Bridge; and they were, we believe, partially adopted for small vessels; such masts, from their cylindrical figure, being stronger than solid masts, containing a similar mass or weight of materials.
Sir Robert Seppings has likewise distinguished himself, amongst his other improvements in ship building, in the construction of masts, for which he took out a patent; the specification of which informs us that, for ships of the line, frigates, and large merchantmen, whose masts are more than 33 inches in diameter, they are to be composed of twelve principal pieces, in the following manner. Four pieces of small square balk timber are to be united diagonally, so as to form a hollow square in the centre. Externally on each of these four pieces are to be tree-nailed two additional pieces. The twelve pieces thus united, are now to have their angular edges cut away, and planed down, so as to bring the whole to a circular figure, when an iron hoop is to be placed round them, and the angular spaces filled up with slips of wood. In connecting the pieces of timber so as to form the required length of mast, bars of iron are to be inserted longitudinally into mortices made in both to receive them; and the several pieces are to cross each other or "break-joint." In constructing the masts for smaller vessels than before mentioned, only eight or four balk timbers are to be employed, (according to their dimensions,) which are to be connected longitudinally and transversely in a similar manner to that described.
Hollow masts so formed, are not only much stronger than when solid, but they effect a great economy in the cost, in the facility of making, and of transportation.
A patent for "Improvements in Masting Vessels," was taken out in 1826, by Mr. Thomas Guppy, of Bristol; from the enrolled specification of which, we collect the following information, exhibiting the principal features of the invention. Instead of a single pole fixed in the keel, in nearly a vertical position, constituting what is called a mast, the patentee employs two poles or spars, the heels of which are fixed on to the opposite extremities of the beam of a vessel, and likewise to the sides; the poles are then so inclined to one another, as to be connected at their upper ends, and thus form with the line of the deck an isosceles triangle; this is the outline of the construction as applied to sloops, or ordinary fore and aft rigged vessels. For square rigged or larger vessels, the poles are not joined at their upper extremities, but at several feet below it, where they cross one another, presenting the figure of an open pair of shears. In all cases, however, the lower ends of the poles are fastened in the situation and in the manner before-mentioned. Thus situated, they are invested with the important property or capability of being lowered forward or aft, as the occasion may render desirable, by the employment of hinge joints at their extremities, close to the deck.
At the junction of the poles above, suitable arrangements are made for the fixing of top masts therein, which are provided with gear for that purpose, as well as for the masting of other vessels; for loading or unloading vessels; and for those other purposes for which sheers are usually employed on board of ships. The principal rigging for these "double pole masts" are the fore and aft stays, the ordinary side shrouds being comparatively unimportant, except for the purpose of going aloft. At Fig. 1 in the annexed engraving a a are the two poles, having joints at bb, from whence proceeds a strong iron band which clasps the opposite ends of the beam c, which underneath diverges into two iron straps, that are bolted to the side of the vessel. This arrangement is explained by Fig. 4, which exhibits a perspective side view of the iron work which connects the poles to the vessel, with a portion of the beam, and a pole c c is the beam, with the iron band bolted to it, and showing the straps d d that are secured to the sides of the vessel, and are turned up flatways towards them.
The poles are connected together at e by a stout iron band, by scarfing and crossing each other, as shown by the separate Fig. 2 in perspective; f is the top, where the upper ends of the poles are strongly secured to one another by straps and bolts; g is the lower end of the top-mast, which passes through a hole adapted to it in the top, with its heel resting upon an iron projection, which is of one piece with the band e. For sloops and fore and aft rigged vessels generally, the poles a a terminate at their junction, and are united by scarfing, previous to putting on the strong iron band. The mode of scarfing the patentee leaves to the genius of the mast maker, but at the same time points out one mode which he most approves of, and which, perhaps, cannot be much excelled. This mode is shown in the perspective sketch, Fig. 3 Connected to the band which unites the poles together, are fixed long iron links ii, for hooking in, or seizing the shrouds to.
A few years ago Lieut. Molyneux Shuldham, R.N. took out a patent for revolving masts, the enrolled specification of which exhibits in sixty-five diagrams and designs, numerous modifications and applications of the principle to various descriptions of inland as well as sea-going vessels. As our space will only admit of a brief outline of the nature of the invention, we must refer the reader who may be solicitous for the details, to the inrolled document in Chancery-lane, and to some beautiful models illustrative of the inventions (constructed by the talented inventor's own hands), exhibited at the National Museum of the Mechanical Arts, in Leicester-square, London. The mast instead of being, as in ordinary vessels, a fixture, is herein made to revolve upon its axis, or turn horizontally upon its heel, carrying with it the sails, yards, and other rigging attached to it, and thereby instantly changes the direction of the vessel's motion. The power required to perform these evolutions may be the wind or manual labour, or both conjointly.
As the action of the wind will naturally tend to produce the desired effect in both cases, whatever manual force may be required to assist the operation must be very little indeed; that is to say, according to modern phraseology, the maximum of effect is produced by a minimum of labour. It will be evident from this arrangement of the machinery of a ship, that fewer hands will be required to work it, that the running rigging may be much simplified and curtailed, and the wear and tear greatly reduced. These improvements are considered applicable to open boats, deck boats, and small craft in general; to vessels employed in inland navigation, coasting vessels, and particularly those navigating intricate channels and rivers. But Mr. Shuldham does not consider them applicable to vessels of war and vessels of small tonnage, that carry lumber in their decks, owing to the room required for the revolving bases of the masts. The masts are variously supported, according to the tonnage of the vessels: in decked boats and small vessels, an iron or wooden pivot is sufficient; in larger vessels anti-friction rollers are fixed to the revolving base, which work between two annular plates, secured to the gunwhales and deck.