STEAM NAVIGATION.) She was built Mr. T. Collyer, in 1850. She is not the largest, but is the fastest wooden steamer in the Northern States. Her di mensions are, length, 260 feet; breadth, 34.08 feet; depth amidships from bare line to deck line, round of beam deduct ed, 9/5 feet ; area of her immersed mid ship section, 119 square feet. Diameter of the cylinder, 56 inches ; stroke of pis ton, 12 feet; diameter of the water wheel, 84 feet ; face of wheel, 9 feet 6 inches ; width of the bucket, 24 inches ; calculat ed dip, 9 inches. Vertical beam engine. Balance valves with Stevens' cut of The weight of the boiler is 87,487 lbs. Weight of the boat at 4 feet draft of water, 147 tons 417 lbs.
In river steamers there should be a due relation between the proportion of the boiler and the wheels. When the latter turns fast enough to reduce the pressure in the there is either more wheel or more boiler required. Mr. Stevens proposes to increase the speed of steam boats, by interposing a stratum of air be tween the flat surface of the bottom and the water. Mr. S. has effected little with this himself, although he has built a vessel little inferior in speed to any wooden boat of equal length on the Hud son, viz., an iron boat of 280 feet long, and. unusual shape.
Ocean steamships for speed require to have their bows made very sharp, so that even at the highest speed even the smallest resistance be not generated. A full bow generates resistance, and to drive that form of bow on with increased force, is only increasing the resistance and the dif ficulty. When it is very sharp, however, she has no buoyancy, and becomes very wet, or liable to ship seas. 1f speed be required in ocean steam-ships, they must have length. The steam-ship Georgia, alrcedy alluded to, is the quickest sailing steamer in the United States. She has the small end ahead, and has run 1000 miles within 60 consecutive hours, or equal to 400 miles per day. Her mean load line of draught is 16 feet, beimg all that is available in running to New Or leans.
The coasting vessels of the United States combine great variety of shape and dimensions. There are vessels built
of considerable size which run on a draught of 8 feet, and from that np to 10 feet, and are on account of their breadth the most stable vessels in the world. Some have a eentre-board or movable keel ; some have a deep keel ,• some have no centre-board, and a small keel. There are a large class of vessels built in New England principally for, and engaged in, the lumber trade, which not unfrequently carry from one-half to live eighths of their cargo on deck. Almost all the yellow pine timber brought from the south comes in these, vessels. The timber which is in the log, and very long (55 to 75 feet), is carried on deck, while the shorter lengths are taken in the bold, through a lumber port cut in the bow immediately below the deck. Their great fault is lowness of the bow, rendering them so liable to ship seas and get wreck ed.
The famous Baltimore dippers are now being superseded, as being too small— the increased speed not making up the difference in dimensions. They are also too deep for the coasting trade of this country. Clipper ships of large size, with comparatively less draft of water, are now being built to a great extent along the eastern coasts, especially in this city (N. Y.) and in Maine. The pilot boats are not only the best, but the fastest vessels on our coast. These are vertically shag in their bows, and thus part the water while vessels with round bows ride over it. One of these, the Mary 7'aylor, built by Mr. S. Steers, of New York, is looked upon as the model craft of this kind of vessel, and has far surpassed the expecta tion of her owners.
The river sloops, rigged like English cutters, are also very fast sailing vessels, and carry on much of the inland com merce of this country. They are chiefly employed on the Hudson and East Rivers, (N. Y.) in carrying freight. Their great breadth enables them to carry enormous deck loads. The round of the deck transversely exceeds that of any other kind of vessel, being often more than 12 inches in 26 feet.