It has been considered by nautical men, that the repeated success of the United States frigates over those of the British, during the•recent war, was chiefly owing to the rapidity with which the former shot away the rigging of the British. To provide a better mode of securing the shrouds to advantage, of saving the expense of rolling-tackles, besides strengthening the yard in the slings and quarter, Fig. 3, a and b, on the next page, represent two square iron straps, fitted on the mast head, one above the other; they have three hooks on each side of them to receive the tops of the shrouds ; those above are placed so as to alternate with those below, as shown in Fig. 2, in order to give room for the eyes of the shrouds, and to let them come sufficiently close ; a and b show the shrouds fixed on the hooks c c. The masts of ships subsequently occupied the attention of Lieut.Green, who devised a plan for effecting the above object, which was deemed worthy of an honorary medal from the Society of Arts. The masts of ships, it should be observed, are secured in two directions ; longitudinally, by means of long ropes called stays ; and in a transverse direction, by means of other ropes Galled shrouds, each of which has a loop in the middle, which is passed over the head of the mast. Each pair of shrouds may therefore be con sidered as forming the sides of an isosceles triangle, of which the apex is the mast head; and being in pairs, it necessarily follows, that if one is shot away, the opposite shroud becomes nearly useless. Lieut. Green therefore proposed that the shrouds should be single, and that each should be terminated at top in a strong iron hook, to take hold in an eye fixed in a strap at the mast head.
Another improvement proposed by the same officer is in the method of slinging the top-sail-yards, by the yard, where it comes in contact with the mast, a kind of clasp or crutch, similar to that at present applied to the main boom ; which, by half embracing the mast, serves to steady the yard, and to prevent those violent jerks, by which in blowing weather men are not unfrequently thrown from the yards into the sea ; it has the farther top-sail-yard, having chocks d d to embrace the top-mast half round, and thereby prevent the yard swinging endways. Fig. 3 shows a bird's eye view of part of the yard c e, and of chocks d d embracing the mast. Fig. 1, e e, the braces of the top-sail-yard ; they are fixed at f, pass through the blocks at g g at the yard-arms, then through the blocks k k. and are secured at L Under the head Doc: has been described the usual mechanical arrangements and process for building and repairing ships. In this place we shall add a very ingenious and improved method of bringing up ships upon the ways for the operations of the ship builder. A Committee of Inventions appointed in the -year I827, by the Franklin Institute of Philadelphia, to whom the iubject was 'referred, drew up the following report thereon, which seems to have been dictated by sound judgment and impartiality. "The Committe of Inventions, to •whom' have been submitted a model, drawings, and descriptions of the " Radiating Railways for the repairing of Vessels,' invented by Edward Clark, New York, ejeil engineer, report, that they have carefully examined the proposed improvftent, and consider the plan as offering great facilities, when it is desirable to have several vessels under repair upon the ways at the same lime. Morton's patent slip, which is in use in Scotland, is of sufficient length -to contain two or three teasels ; but it is evident that whichever was the last 'hauled up, must be the first launched; and they must, therefore, be frequently 'repaired in haste, without being allowed that time to dry, which is, in many leases, a point of great importance. To obviate this difficulty is the end in the plan under consideration. does not appear, from any thing which as been presented to the Committee, that Mr. Clark proposes any thing novel iu the construction of the lower part of the railway, or of the carriage upon which the vessel is to be drawn up; its distinguishing feature being the means provided for removing vessels out of the direct line of the main railway, and of depositing them upon sub-ways, for the purpose of being repaired. To ac complish this purpose the upper part of the railway, for a length sufficient to receive a vessel, is detached from the lower part, and is made capable of revolving upon a firm horizontal platform, a perpendicular shaft from which through the upper end of the detached part of the railway. This plat
passes is the segment of a circle, but it may, if necessary, present a complete ciscle. At the periphery of this segment, the'fixed part of the railway terminates, and the detached revolving commences ; this is supported upon the platform by • sufficient number of strong iron rollers, placed transversely on the lower part of the framework of which it is formed. The upright shaft, around which the detached railway is capable of revolving, is also the shaft of the windlass, by which the vessels are to be drawn up ; this detached way may therefore be con sidered as a radius to the circle, of which the platform is a segment. When • ship is drawn up and has arrived upon the movable part of the railway, a power may be applied to carry this with its load to the requisite distance round the circular platform, until it arrives at a sub-way, several of which are erected round the platform, forming produced radii to the circle. These are precisely similar to the main railway, with the exception of their not being continued to the water, but only of such a length as to admit of the carriage with its load being lowered, and deposited upon them until the intended repairs are made. In the diawing which accompanies this report there are represented six nib-ways, and of course upon such a structure seven vessels might be placed at • time. The main expense attending the erection of marine railways, is in constructing that part which is under water, where nearly the whole of the labour must be performed in the diving bell. In the mode proposed by Mr. Clark, one marine railway would be sufficient in those parts where many vessels may be required to be hauled up ; a considerable number of sub-ways, with their appurtenances, might undoubtedly be provided at an expense far below that which would attend the original structure. After maturely considering the subject, the Committee are fully convinced of the practicability of the plan, and also of its economy, in those situations where more than a single railway would be desirable. When once constructed, if possesses the advantage of being capable of extension in the number of its sub-ways, whenever it may be required." Annexed are engraving! from the drawings referred to. Fig. 1 is a bird's eye view of the oplatforM and railways. A, revolving section of the 'railway, •rhich may •at pleasure be made to coincide and connect with the radiating or sub-ways B B B, 'or with the main railway C, extending into the water. D is the shaft or pivot upon which the section A revolves. Fig. 2 represents the revolving seed011, 'with its centre, as in Fig. 1, together with the circular iron railways, upon 'which the cast-iron rollers are to run. Fig. 3 is an elevation or side view of the 'revolving and permanent railways, supporting a ship's carriage ; A being the convolving section ; B or C, •'cation of the main, or the sub-railway ; D shaft fur communicating to the windlats the power which is generated at the levers if; this shaft is also the pivot around which the section A is made to revolve ; e e e e, &c., are iron rollers connected to and supporting the revolving section in the circular railways ; 0, ship's carriage resting on the inclined railways ; H, windlass or other machinery for elevating vessels ; i, chain by which the carriage is drawn up ; k, palls to prevent the carriage from running back ; 1, friclion rollers, flying between the movable and fixed ways. Pig. 4, ground view of a ship's carriage. Mg. 5 transverse view on a larger scale of a ship's carriage on the railways; • a cuneiform blocks, movable on rollers, in appropriate grooves, to prevent lateral motion ; b b, bilge blocks moving on pivots, and resting on rollers adapted to s a; c e, ropes by which the cuneiform or wedge blocks are drawn up, and the bilge blocks forced against, and adapted to, the bottoms of vessels.--Pranklin Journal. For a variety of information of the constituent parts of ships, with their recent ameliorations, see the separate heads, as MASTS, XUDDIHIS, CAPSTAN, WINDLASS, BLOCKS, ANCHORS, Floe, BOATS, &c. &C.