US 1263052 A
Description (OCR text may contain errors)
0Q H. FOWLER.
Patented Aim 16, 1918.
2 SHEETS-SHEET 1.
INVENTOR 'ATTORIVEV c. HQ FOWLER.
TUNNEL BOAT. APPLICATION FILED JAN-15.1916.
. IIVI/EIVTOR I M1734 2 SHEETS-SHEET 2.
Patented Apr. 16,1918.
A r'romvm 2 I it FEQQ CARL H. FOWLER, or NEW roan, iv. Y.
Application filed. January 15, 1916. Serial No. 72,201,
To all whom it may concern:
Be it known that 1 CARL H. FOWLER, a citizen of the United States, residing in the city, county, and State of New York, have invented certain new and useful Improvements in Tunnel-Boats, of which the following is a specification.
My invention relates especially to boats of light draft, adapted to navigate through shallow water, which boats are provided 7 with tunnels or chambers within the body of the b=oat,'in which screw-propellers are situated. Boats of this character are described in my Patent N 0. 1,132,923, granted March 23, 1915, for improvements in shallow water boats. As is there described, the tunnel or tunnels have a vacuum pump connected therewith, and preferably a vacuum chamber superimposed above the tunnel or tunnels in which water is raised to a desired level by the operation of the vacuum pump, the bottoms of the tunnels being openin the bottom of the boat, so that thetunnels and vacuum chamber above the same are constantly, during operation, filled with water in which the propellers are entirely submerged, the water usually extending for a number of feet above the propeller in a vacuum chamber. This construction makes practicable the operation of the propeller in water of density equal to that it wouldhave if situated the same number of feet beneath the bottom of an ordinary boat.
My present invention relates to improvements in the type of boat referred to, which make for greater efliciency and economy of construction, operation and space. A part of my invention consists in operating a relatively small propeller in a tunnel of correspondingly small cross-section at high speed by suitably connecting the propeller shaft by gears or preferably by a chain drive, to an engine of relatively slow speed. Tunnel boats of the old type heretofore have been, so far as I am aware, direct-connected to the prime mover, and have been found tov have a limited range of usefulness. In my improved construction I drive the propeller at in increased speed (as for example twice as many revolutions per minute as the shaft of the engine from which power is taken) and thus reduce the necessary diameter and size of the propeller, so that its effective equal to that of a larger propeller rotated more slowly by direct connectionwith the engine. This procedure is rendered more efficient by the use of a vacuum chamber above the tunnel, as stated, whereby a firm body of water is provided at the point at which the propeller operates. It is a matter of common knowledge that a small propeller at high speed in the ordinary boat in shallow water is almost useless for it produces cavitation to such an extent that it churns up an exceedingly foamy medium of poor resisting power in which to operate. For this reason a high speed propeller in shallow water has heretofore never been practicable or efficient. My present invention overcomes these difficulties.
Another feature of my invention consists in the use of a plurality of comparatively small tunnels, distributed through the length of the boat, some in the fore part,some in the center, and some in the afterpart'of a comparatively long boat. may be situated in longitudinal alinement or in one or moreseries of tunnels, each series comprising tunnels in longitudinal alinement, and each tunnel or group of tunnels containing a propeller or propellers operated from a separate engine, or by chain drive from one central shafting. Thus a boat may be provided with, for example, two, three or more tunnels in one line or on each side, the propellers in the forward pair of tunnels being 7 driven preferably by a speed-increasing chain or gear drive from an engine of comparatively slow speed. The next or second pair of propellers can be similarly operated by a separate engine, and the third or rear pair of propellers operated by a third engine. Under this arrangement allowance can be made for the backward speed of the water as thrust from the first propellers and partly received into the tunnels of the second and succeeding propellers. This canbe compensated either by increasing the propeller speed of the second propellers by means of the sprockets and chains or by direct engine control of the second engine, or also by increasing the pitch of the second and each successive propeller blades themselves.
The arrangement herein described makes possible the use of short shafting only and the distribution of the propelling power in small units throughout the length of the boat, and does not concentrate the strain of propulsion at the extreme stern, or at one point, as do most boats. On the contrary,
These tunnels oration.
V hull construction can A number of advantages arise from the construction described By using the chain drive with difierent sprockets a wide variation of propeller speed can be obtained without changing the engine speed, thus making possible the finest adjustments especially when a series of tunnels are installed. .The use of the chain drive makes it practicable to place the engine with. its power shaft either above or below or to the side of the propeller shaft, and also does away with the necessity for absolutely perfect and rigid alinement. By increasing the propeller speed and reducing the diameter of the'propeller and tunnel from that which would otherwise be necessary, the dead weight of the water carried by the tunnel is very considerably decreased since the weight of the water in the tunnel varies approximately as the cube of the diameter of the propeller. Also, the space occupied in the boat by the tunnel or tunnels is correspondingly decreased, leaving more room in the hull available for carrying freight or passengers. High speed engines are much more expensive and less durable than slower engines. The life of an engine is much greater when it is operated at mod erate speeds than at high speeds. In my device less expensive engines of low or moderate speeds may be successfully used, while at the same time the propeller is rotated efficiently at much higher speed. Owing to the distribution and division of the power units of propulsion throughout the length of the boat, a lighter and less expensive form of be used than would otherwise be practicable.
In order that. a clearer understanding of my invention may be had, attention is hereby directed tov the accompanying drawings forming part of this application and illustrating certain embodiments of my invention. In the drawings, Figure 1 represents a plan view of the boat equipped with one form of my invention, Fig. 2 is a vertical section of the. same taken on line 2-2 of Fig. 1, Figs. 3 and 4: are cross-sections taken. on lines 33 and l4 respectively of Fig. 2, Fig. 5 is a plan view of a boat having a pair of tunnels, one at each side of the boat, Fig. 6 is a plan view of a boathaving a plurality of tunnels in pairs, in connection with a pluropeller chamber :2 which preferably has a orward wall 3 sloping upwardly with a gradual curve from the keel line and rearwardly, and a rear upper wall 4 sloping rearwardly and downwardly. The tunnel 2 terminates in the stern of the boat at a point. below the minimum water line and preferably above the keel line of the boat. The cross-section of the tunnel is preferably as shown in Fig. 3. The stand-pipe or vacuum chamber 5 is mounted above and connects with the highest point of chamber 2, vacuum chamber 5' communicating by a passage 6 with a vacuum pump (not shown), whereby the tunnel 2 and vacuum chamber 5 may be filled, to as great an extent as is desired, with water drawn through the bottom of chamber 2.
The propeller shaft '7 extends through a suitable bearing 8 into the tunnel or propeller chamber 2 and is provided therein with the propeller 9. The opposite or forward end of shaft 7 is provided with a bearing 10, which preferably comprises a thrust bearing, to take the forward thrust of the shaft when the propeller is advancing. Bearing 8 should be provided with means for taking the rearward thrust of the propeller shaft when the propeller is reversed. In the preferred construction both the shaft 7 and the upper rear wall l of the tunnel slope downwardly toward the rear at the same slight inclination.
The engine 11, which may be any suitable prime mover, such as an internal combustion engine, has a shaft 12 supported in a bearing 18. Shafts 12 and 7 are provided with sprocket-wheel's 14 and 15 over which sprocket chain 16 operates, sprocket it being of a considerably larger diameter, such for example as twice the diameter of sprocket 15, so that shaft 7 and propeller 9 rotate at a considerably higher rate than on gine shaft 12. Gear connections may, of course, be used instead of the sprocket chain drive, but the latter are considered preferable.
It is, of course, understood that the drive described rotates propeller 9 at a rate of considerable velocity, and that propeller 9 is accordingly of a much smaller diameter than would otherwise be practicable for driv-- ing the boat at the same speed. It should be noted that while I speak of the propeller as being situated within tunnel 2, this should not be taken as meaning that the propeller is necessarily situated entirely within the lines of the hull, since the same may ex tend somewhat beneath the keel line of the boat when it is not essential that the draft of the boat be at a minimum. It is, however, essential that means, such as the stand pipe 5 and the connection from the same to p a vacuum pump, be provided to cause the propeller to rotate in water having a density and firmness equivalent to that which would be encountered, if the propeller were located at a considerable distance beneath the surface of the water navigated. It should also be understood that the tunnel extends no farther upwardly within the boat than is necessary to accommodate the propeller, so that usually the highest point of the propeller chamber proper situated above the propeller is in substantially the same hori 'zontal plane as the upper edge of the propeller wheel. As has been explained above, the weight of dead water carried in tunnel 2 is greatly decreased by thus decreasing the diameter of the propeller wheel and dimensions of the tunnel, with a consequent economy of power.
A low limit is ordinarily found for the efiicient operation of screw propellers in shallow waters. This is because of the fact that at greater speeds the propeller cavitates, power is wasted and all efiiciency lost. With my construction this result is overcome by the solid water being given to the" propeller at all times by use of atmospheric pressure, because of the suction exerted in the vacuum chamber by the vacuum pump, so that the propeller can effectively be operated at a considerable speed.
In Fig. 5 the boat 1 is shown as provided with a pair of tunnels 2, 2, each of which may be imilar in construction to the tunnel shown in Fig. 2. These'tunnels are located One at each side of the boat and are provided with superimposed vacuum cham bers 5, 5, as shown in Fig. 8, these vacuum chambers being connected with a vacuum pump as described above. The propellers 9, 9 are mounted within tunnels 2, 2 on shafts 7', 7 which extend into the interior of the boat in the same manner as shaft 7 in the form of my device already described. The shaft 12 of engine 11 is provided with a pair of similar sprocket-wheels 14, 14, sprocket 14 being connected by sprocket chain 16 with a smaller sprocket 15 on one shaft 7 and sprocket 14 being connected by chain 16 with a sprocket 15, similar to sprocket 15, on the other shaft 7 By this means propellers 9 9 are rotated at a speed considerably higher than that of the engine shaft and the diameters of the propellers and cross-sections of the tunnels are correspondingly reduced.
In a pleasure boat the tops of the tunnels may be utilized as supports for seats and lockers. In a freight carrying boat, such as a canal boat, on which all or a. greater part of the load is carried as a deck load and not be located in the otherwise Waste'space under the deck.
In Figs. 6, 7, 8 and 9, a construction is shown in which a series of tunnels 1 2, 3, etc., are placed in longitudinal alinement adjacent one side of the boat and a second series of similar tunnels 1 2 3 etc., are placed in longitudinal alinement adjacent the other side of the boat, the forward tunnels 1 and: 1 being alined transversely of the boat and the other pairs of tunnels of the two series being similarly arranged. In this instance the rear pair of tunnels are similar to the tunnel shown in F ig. 2, with the rear orifices thereof preferably extending through the stern of the boat at a point between the minimum water line and the keel line. The rear walls of the other tunnels extend downwardly to the keel line of the boat, the cross-sections of all the tunnels being the same as shown in Fig. 8.- Each tunnel is provided with a vacuum chamber 5, or if desired a common vacuum chamber may be provided for each transverse pair of tunnels suitably connected. A single vacuum pump may be provided for the whole system with suitable connections to the differ- 'ent vacuum chambers, or a separate pump may be provided for each transverse pair of tunnels. An engine 11" is provided for the forward pair of tunnels, the engine shaft 12 being suitably connected, as by sprocket chains 16 and 16 in the manner already described, to the shafts 7 7 of the propellers located within the forward pair of tunnels. Other engines, such as 11 and 11 are similarly connected to the propeller shafts belonging to the other transverse pairs of tunnels. With this arrangement it is obvious that a considerable amount" of power may be utilized while keeping the sizes of the engines and the cross sectional areas of the tunnels very low. This arrangement is especially valuable for'use on a long non-rigid barge or boats such as are used in various rivers. It is in brief applying to boat construction in a practical way the division of its power propulsion into a large number of small units throughout the length similar in principle to the centipede with its series of propeller power units.
It should be understood that my invention is not limited strictly to the exact details of construction described, but is as broad as is indicated by'the accompanying claims.
Havlng now particularly described my invention, what I claim and desire to protect by Letters Patent is as follows 1. A boat having a series of tunnel chambers open at the bottom and longitudinally arranged, shafts extending into said chambers from the interior of the boat, propellers &
thereon within said chambers, power-generating means, and connections between the same and said propeller shafts.
2. A boat, having a series of tunnel chambers-open at the bottom and longitudinally arranged, shafts extending into said chambers from the interior of said boat, propellers thereon Within said chambers, a plurality of engines and speed changing connections for driving said propeller shafts at speeds greater than the speeds of said engines.
3. A boat, having a longitudinal series of chambers therein, open at the bottom of the boat, with vacuum chambers above and connectedtherewith, shafts extending into said cltambers from the interior of the boat, propellers thereon, Within said chambers, vacminn-creating means for raising the Water within said propeller and vacuum chambers, a plurality of engines and speed changing connections for driving said propeller shafts at difierent speeds from the speeds of said engines.
a. A boat having a plurality of series of longitudinal propeller chambers, open through the bottom of the boat, shafts extending into said propeller chambers from chambers appertaining thereto, for driving said propeller shafts at speeds greater than those of the engines.
5. A boat, having a plurality of series of longitudinal propeller chambers, open through the bottom of the boat, With vac uum chambers above and connected With said propeller chambers, With vacuum creating means for exhausting the air from said vacuum chambers, shafts extending into said propeller chambersfrom the interior of the boat, propellers on said shafts Within said chambers, a plurality of engines, speed increasing connections between said engines and the propeller shafts of the propeller chambers adjacent thereto.
This specification signed and witnessed this 11th day of January, I
J. H. WEBER, H. R. BROWN.
Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,
Washington, D. G.