The Flying Fish was an extreme clipper ship of 1505 tons launched in September 1851, from Donald McKay's East Boston Shipyard. Flying Fish much resembled Flying Cloud in appearance, but was sharper in the ends and not quite as large and lofty as her sister ship, with a spread of canvas of 8250 yards. Juxtaposed to her bow was a figurehead of a green and gold flying fish that conveyed a sense of speed.

This is the fourth clipper which Mr. McKay has built during the past year, and all of them may be regarded as experiments, for they bear little resemblance to other vessels, or to one another. The Stag Hound, the first, has round lines, and 40 inches dead rise at half floor; the Flying Cloud concave lines, and 30 inches dead rise; the "Staffordshire," though fuller in the ends than the others, also has hollow lines, but only 20 inches dead rise, and the Flying Fish is the sharpest of all in the ends, though is not so long as either that of the Flying Cloud or the Stag Hound, and her dead rise is but 20 inches. All these vessels are timbered round the sterns and planked up flush to the covering board; but as will be seen by the variations in the angles of the floors, they are all of a different model. To this variation, which is peculiar to all our scientific ship-builders, may be attributed the matchless speed of our ships. Mr. McKay is one of those who believe that a perfect model for speed, with fair carrying qualities, has not yet been discovered, and hence, in every ship he designs, he tries to make some improvement. The Flying Fish is the embodiment of his idea of swiftness, with good stowage capacity. She registers 1566 tons, and stows a very large cargo for her register. The variation in the angle of her bottom and the form of her ends gives her greater capacity, and more buoyancy; and as her bow, towards the extreme, is even sharper, she is expected to sail fast as the Flying Cloud.

The Flying Fish is 202 feet long on the keel, 210 feet between perpendiculars on deck, and 220 feet over all. Her extreme breadth of beam is 40 feet, and is precisely at the centre of her loud displacement line; the angle of her bow at the same line is 17 degrees, and her stern 20 degrees, and her whole depth at the main hatchway 22 feet, including 7 feet, 10 inches height of between decks; but as she is carried up boldly forward, her depth at the fore hatchway is a foot more. Her sheer is about 3 feet, and the rounding of her sides about 12 inches. In outline she is plain but beautiful. The representation of a flying fish for a head, neatly carved and burnished with gold and green, is her only ornament on the extreme, for she has neither head nor trail boards, nor even shocks around the hawseholes, nor is the bow lumbered with rigging, for all her head stays lead in-board and set up under the topgallant forecastle. Her name is carved in the monkey bulwarks along the curve of her bow, and is gilded, and the ends of her cat-heads are also ornamented with gilded carved work. Her bow, as already remarked, rises boldly, and is most beautiful in its form and outline. The moulding of her planksheer is carried around the stern, and the run planking is carried up to it. She is three degrees fuller on the load lone aft than forward, but when launched she drew 1 foot more by the stern than the bow; but still her run is very clean, and faultless in form. A beautiful arch of carved work, and her name, etc., ornament the stern.

She is sheathed with yellow metal up to 18 1/2 feet forward, and to 19 feet aft; the rest of her hull is black outside - a color peculiar to clippers and the clergy. Inside her bulwarks, etc., are painted pearl color, and the waterways blue.

She has a topgallant forecastle the height of the main rail, and in its after wings are companions, which lead to the sailors' quarters below; and before the companions are water closets, and along the sides, lockers, etc. The accommodations for the crew occupy the angle of the bow, are lofty, well lighted, and ventilated.

She has a trunk cabin, built into a half poop-deck, with ample steering room aft, and good gangways. She has two cabins. The first contains three state-rooms, the pantry, and a bread locker, and is neatly painted and ornamented. The after cabin contains six state-rooms, and a water closet, with a recess on each side, and a companion, which leads to the deck aft. It is splendidly furnished, with mahogany, rosewood, etc., has a large centre table, sofa in the recesses, and mirrors, which multiply its beauties at every turn. The space abaft, under the poop, is a store-room, with a skylight over it, which also answers for a hatchway; and the space along the wings in the officers' and steward's rooms, are fitted with drawers, suitable for stores of various kinds.

Her accommodations forward and aft are all that could be desired for safety or comfort, and correspond well with her other arrangements. Leaving ample deck room for working ship.

She has a strongly secured patent windlass, and Crane's patent chain stoppers, which, by the way, ought to be adopted in every ship. They are simple in their design, economical in their cost, and of the highest utility in saving every link of chain as it is hove in. They are secured to a breast-hook close inside of the hawsehole, and the chain passes over an iron ridge, and every link as it is hove in is nipped by a paul which falls upon it, consequently its fleeting or surging upon the windlass will not lose a single link. It supersedes entirely the use of the devil's claw. When the chain is required to be paid out, the paul is triced up out of the way, leaving fair scope for running.

She has two beautiful mahogany capstans, brass mounted, one on the topgallant forecastle, the other on the quarter deck, Litchfield's patent pumps, and Reed's patent steering apparatus. Abaft the mainmast she has a cylindrical iron tank, nearly her whole depth, and capable of holding 5000 gallons of water.

She has five boats of the most approved models, either for braving heavy sea or landing in the surf. Her ground tackle in weight and length comes up to the highest requirements of Lloyd's. In every detail of her furniture no expense has been spared to make her perfectly complete.

As the above will convey a fair idea of her hull, in its outline, and some of its appointments, we will now give the leading details of her construction. Her keel is of rock maple and oak, in three depths, which combined, moulds 3 feet 2 inches, and sides 16 inches. The floor timbers are moulded 18 inches, and sided from 10 to 12, and over them are two depths of midship keelsons, each 15 inches square and alongside of these are sister keelsons 14 inches square. The floor timbers are bolted alternately through the first keelson and the keel, so that there is an inch and a quarter bolt through every floor timber and the keel. The upper keelson is bolted through every navel timber--the bolts driven blunt into the keel, within three inches of the base. The sister keelsons are bolted horizontally through each other and the lower depth of the midship keelson, and diagonally through the navel timbers into the keel. The ceiling of the floor is 4 1/2 inches thick, and over the first futtocks are two bilge keelsons, each 14 by 15 inches. Above these three are four strakes of 10 by 14 graduated to 8 inches thickness, which continues the same in substance up to the deck. To avoid repetition, we may as well state, once and for all, that she is square fastened throughout, from the keelsons to the covering-board, the fastening varying from 1 1/4 inch to 7/8 of an inch. Under the lower ends of the hanging knees is a stringer of 14 by 12 inches. The hanging and lodging knees in the hold are of oak, and the former have 18 bolts and 4 spikes in each, and the latter meet and scarph in every berth, and are closely bolted. She has 4 oak pointers forward, and the same number aft, and all are filled in with hooks. Some of the pointers extend nearly 30 feet on each side, along the skin, and none of them are less than 12 inches square, except where they taper at the ends. The hold stanchions are 10 inches square, kneed above and below, in the wake of the hatchways, and elsewhere they are clasped with iron to the beams and keelson, and bolted through both. Her deck beams are of southern pine--those under the lower deck are 15 by 16 inches, amidships, and those under the upper deck 10 by 16.

The between decks waterways are 15 inches square, the standing strake over them 10 by 16, and that inside of them 9 by 12, closely bolted vertically and horizontally. The ceiling above is 5 inches thick. Her ends in he between decks are spanned by massive hooks, alternately bolted from both sides, that is, from the inside to the outside, and vice versa. The between decks handing knees, like those below, have in the body of the vessel 18 bolts and 4 spikes in each, and the stanchions are turned and secured in the usual style.

Her upper deck waterways are 12 inches square, with two 4 1/2 inch strakes inside of them, let into the beams below. The lower deck is of hard pine, 3 1/2 inches thick, and the upper deck of white pine of the same substance.

Her garboards are 7 inches thick, let into the keel, and are bolted through it and each other, upward through the timbers. The bottom planking is 4 1/2 inches thick, and her wales, which are 6 by 7 inches, are carried up flush to the planksheer. Her treenails, bilge and butt bolts, have been driven with more than ordinary care. Her planksheer and main rail are each 6 inches thick, and the latter is strengthened by a 5 inch rack rail, which extends from the bluff of the bow to the turn of the stern.

Her bulwarks are 4 1/2 feet high, amidships, surmounted by a monkey rail of 16 inches and the poop is protected by a rail supported on turned stanchions. Her bulwarks are neatly tongued and grooved, and her sides are smooth as glass, the planking fair and regular, and her outline, as a picture, faultlessly beautiful.

Her frame is mostly of white oak, and her planking and ceiling of hard pine. She is seasoned with salt, has air ports below, ventilators along the line of her planksheer, and Emerson's corresponding ventilators forward and aft. In materials and fastening, she is second to no ship of her size, and in workmanship and finish, she has no superior.

Her heavy standing rigging is of four stranded, patent rope, made to order of the best Russian hemp, and varies from 10 1/2 to 8 inch. The running rigging is principally of Manila hemp. Her iron work is the same as that in general use, but stout in proportion to the other details of her rig. She has chain double bobstays and bowsprit shrouds; chain martingale stays and guys, chain topsail sheets and ties, and iron trusses and futtock rigging.

Her fore stays set up to the knight heads, and all her other head stays lead through the bows and set up inboard. The main stays set up to the bitts before the foremast,, and the topmast stays in the fore top. Her lower rigging sets up with dead eyes on the line of the main rail, outside of the monkey rail, and the topmast rigging upon the ends. She has all the fancy sails peculiar to a clipper, such as royal studdingsails, staysails, water sails, a ringtail, etc., and 8250 yards of canvas in a single suit; and if her standing rigging is as good as it appears to be, we apprehend no danger from her being crippled in her spars, for she is the best fitted out ship aloft belonging to this port. Her masts and yards are stouter in the diameters, than those of the largest clippers belonging to New York. Their positions and proportions are beautiful, and fill the eye of the observer with admiration. Her sails when set will make a glorious display. The leaches of the square sails will form a continuous line from the head earrings of the skysails to the clews of the courses, and her fore and aft sails will set like boards. The sails were made by Mr. J. W. Mason executed her ornamental work, and Mr. Mendum was her blacksmith. All employed upon her have done their work well.

She was designed in all her details and built by Mr. McKay at East Boston; and he confidently expects that she will sail as fast as the Flying Cloud, if not faster. Her commander, Capt. Edward C. Nickels, a gentleman of long tried experience and intimately acquainted with the California and China trades, superintended her construction and equipment. No man knows better how to handle a ship, and as he has had the Flying Fish fitted out precisely as he wanted her, he will be expected to make her astonish the swiftest New Yorkers.

Messrs. Sampson & Tappan, of this city, own her. She is now laden, and will sail in a few days for San Francisco. Good luck to her, and may she prove to be the swiftest ship afloat.