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é THE MARINE RECORD. Aucus? 8, I90I. en == THE OVERHEAD FERRY AT ROUEN. (ILLUSTRATED). The crossing of channels has always been a difficult prob- lem to solve, especially when such channels are near the sea and are thereby subject to tides, tidal or ordinary waves, and currents, to which may be added, in northern latitudes, the possibilities and risks of frost. ‘ The chief difficulty arises from the fact that it is necessary for channels in all weathers to retain a free passage, mast high and of great width, in order not to interfere with the rights of navigation. Among the means which the engineer has hitherto had at his disposal for the purpose of crossing rivers or channels may be named: Boats, or ordinary ferries; swing, draw, and bascule bridges; ordinary bridges; tunnels under the bed of channels; traveling carriers. Swing, draw, and bascule bridges are limited to relatively small openings. They can only be used over canals or sea charinels which allow the water traffic to be temporarily inter- rupted and where a vessel can be under perfect control in all weathers, as the navigation is necessarily discontinued when the bridge is closed or lowered. These bridges cannot be used over channels near the open sea, from which a ves- sel some times comes in stress of weather, unable to moderate her speed and make the signals neces- sary for the working of movable bridges. In point of fact, swing, draw, and bascule bridges can be used only over docks or inland canals or rivers. Ordinary bridges are more satisfactory for navi- gation than the preceding, but if they are to cross a river leading to an important harbor, they must be built of such a height that the tallest masted ship may sail underneath, and sometimes these masts reach a height of nearly 200 feet above the water, The approaches to the bridge also involve considerable works in order to reach such great heights, especially when, as is generally the case, the site of the bridge being near a town or masonry quays, a considerable area of land has to be pur- chased in order to provide space for constructing the approaches. It is, then, easy to understand why ordinary bridges crossing channels are so few —their first cost is too heavy. Some of those that exist, however, are remarkable, among which may be named the Forth Bridge in Scotland which is 151 feet above high water, and our own Brooklyn Bridge, at New York, with a height ofonly 135 feet, which nevertheless involved a cost of over $15,000, 000. The system exemplified by the Transbordeur at Rouen, is called by the inventors the transshipping bridge. (pont a transbordeur), and is due to the combined labor of Messrs. De Palacio and Arnodin, to whom M. Brull, a former president of the Society of Civil Engineers in France, lent his assistance for the. verifications of the conditions of stability. The advantages of the system are: As enumera- ted by the Vice Consul at Rouen as follows: The rollers are connected with a movable frame under the line of rails, which may freely move in a longitudinal direc- tion qui e’ close to the platform and from one end to the other of same. We have thusa rudimentary vehicle which can cross the channel without interfering in any way with the opening, which isto remain clear. In order to make this vehicle of practical use, iron rods or cables are attached to the frame, above mentioned, the object of these being to carry a platform, called by the French inventors trans- bordeur, or carrier from shore to shore, hanging at the same level as that of the quays on each bank, but in any case above high water and the reach of waves, The frame can roll over the railsin both directions at pleasure; the suspended carrier can therefore landon one shore or the other at will, as it follows the frame in the same way as the car follows the balloon. In order to obviate any swinging motion which might re- sult from the pressure of the wind or the forward motion of the carrier itself, the rods by which the latter is sus- pended are arranged in triangles, both in the longitudinal and transversal directions. There is thus a little railway for crossing the river, with this difference, that the body of the ANWR) \ cd Cro oe oss. Sites eta: Se = SSS OSS Se SSS OS <a > — eres KOSSSe Bs Reeder nO ee | by «| Sart Hats TTT ‘ a Uy) Lb jmnvege 4 tere el PIECES _ | ! 04 Bagels | ares NO ea eV eR eens if iB i Svan A / sagan!) agaauil|'* bs ine in fact, be at any moment necessary to reverse the direction on account of an unforeseen obstacle. The accompanying cut shows the bridge with a platform part way up the piers. This can be reached by stairs or ele- vators, and used as a restaurant, etc. In the bridge at Rouen, however, this feature was omitted. Tt will be observed that this is the most favorable solution of the problem of crossing maritime channels. The latitude it leaves for fixing dimensions—height or length—without any unreasonable increase in its cost per- mits its use over many rivers and inlets requiring easy com- munications from shore to shore. It affords greater speed and more regularity than a boat, allowing twice or three times as many crossings to be made as with the latter, without being subject to the same causes of interruption. It does not even momentarily interrupt navigation, nor does it compel the traffic to make laborious ascents as in the ordinary bridge, or an ascent and descent to an unpleasant passage through a tunnel. It realizes the minimum distance to be crossed, as its course is straight and horizontal; it consumes very little mo- tive power, and this can be supplied by any kind of motor. Lastly, it is economical in construction. ———— > @ <a __ LAKE MICHIGAN—WIRELESS TELEGRAPHY. The report that the Pere Marquette line had given upits plan of using wireless telegrapy in the operation of its steamers between Ludington and Manitowoc denied by W. IL. Mercereau, superintendent of the company’s steamship line. He says the new system, much like the Marconi system, controlled by the Northwestern Wireless Telephone & Telegraph Co., will be operated shortly between Ludington and Manitowoc, over fifty-six miles of opeu water. The system willalso be put into operation on the steamers of the company if the cost is not,too great, but the crosslake line will be the first to be developed. The new system will probably be in complete operation before the close of the sum- mer. The high elevators which the Pere Mar- quette company owns at Ludington and Manitowoc will obviate the necessity of the erection of the customary high steel towers and when the system is once in operation the frequent delays unavoida- ble in sending messages through Chicago will be ended. At present their are times when a message sent by their roundabout route that a car ferry has left Manitowoc for Ludington is received about the time the boat is entering the harbor. | ge CANAL TO THE COAST. Lieut. C. W. Raymond, of the United States Board of Engineers on deep waterways, haswrit- (1) The channel to be crossed is left entirely clear at all hours, without requiring vessels to ten to A. R. Smith, Superintendent of the Mari- time Association, New York, in connection with transportation from the lakes to foreignports. He says in part: “If a 21-foot ship canal is con- structed from the lakes to the sea in connection make any special signals or modify their rate of speed any more than they would in the case of a cross channel ferry. (2) No increase of distance or ascent or descent is forced on the traffic in order to cross from one shore to the other. The essential part of the system may be described as a horizontal railway supported by a bridge spanning the chan- neland built up at sucha height as will allow the tallest masted vessels frequenting the channel to pass beneath. Any kind of bridge may be used, provided the rectangular opening for navigation is left entirely clear; except that arched bridges, which would reduce that rectangular area, must beexcluded. Suspension bridges, however, owing to the facility they offer for spanning wide channels, the great advantage they possess in permitting erection by ‘‘launch- ing’’ without any/scaffolding interfering with the naviga- tion, the economy of their construction, the little area they offer to wind pressure, and, lastly, their lightness and ele- gance, seem to command preference in the majority of cases. This is the kind of bridge in Rouen. The platform of the bridge carries two lines of rails, over which a carriage on small wheels rolls, the number of wheels varying with the weight to be carried. with theseplans and estimates of the Board of THE OVERHEAD FERRY AT ROUEN, FRANCE. vehicle, instead of being above the rails and wheels as usual, is some 140 or 160 feet below these. It possesses, neverthe- less, the speed and regularity of motion which can be ob- tained on any straight and hor'zontal railway line, with the advantage that, thanks to its long suspension, this new kind of wagon enjoys a smoother motion ‘than the best railway coaches, without the intervention of springs or other expen- sive and cumbersome appliances in order to modify the vibrations. The motion of the frame is obtained, without expending much power, by means of any motor—the kind most suita- ble to local circumstances—cable driven by steam, water under high pressure, compressed air, gas, or oil, or, better still, by electricity. But in the last case the dynamo, in- stead of being erected on shore, as the steam engine, is pre- ferably placed on the movable frame, which it carries along with itself by means of a pinion working into the teeth of a rack fixed to the bridge. Whatever may be the kind of engine employed, it must be able to work backward or forward instantaneously. It may, Engineers on deep waterways, it undoubtedly will be necessary for the state ofNew York to transfer the Erie canal to the federal govern- ment. A ship canal cannot be constructed along the route proposed by our board without interfering with the existing Erie canal. The views of the board were requested by Con- gress as to the comparative advantages of two channels hav- ing depths of 21 and 30 feet respectively. The question whether it is desirable for the United States to construct any deep waterway from the Great Lakes to the Atlantic tide- water was not submitted to the board for consideration and the board has not expressed a direct opinion thereon.” OO OO Oe Ir is understood that the Columbian Iron Works, of Baltimore, Md., have been purchased by a syndicate of moneyed men, headed by a well-known officer on the active list of the Navy, and will soon be prepared for govern- ment contracts on the largest scale. ‘she dry dock of the company has been constantly employed since the rehabili- tation, and the outlook is said to be excellent for a con- tinuance of work during the remainder of the “flush” times in the country.