US1944242A - Marine tractor - Google Patents

Description

Jam 1934. E. JOHNSON 1,944,242

MARINE TRACTOR Fild May 12. 19:52 5 Sheets-Sheet 1 INVENTOR lads Johnson ,mrm

l5 ATTORNEYS E. JOHNSON MARINE TRACTOR Jan. 23, 1934.

3 Sheets-Sheet 2 Filed May 1.2, 1932 INVENTOR Ea le Jb/anson l5 ATTORNEYS Jan. 23, 1934. E. JOHNSON MARINE TRACTOR Filed May 12, 1932 3 Sheets-Sheet 3 INVENTOR Ease? Johnson I 4 zls ATTORNEYS Patented Jan. 23, I934 seine.

MARINE TRACTOR Earls Johnson, Morristown, N. J.

Application May 12, 1932. Serial No. 610,772

3 Claims.

This invention relates to watercraft and more" particularly to a marine tractor for pushing or pulling boats or barges.

Among the objects of this invention are the provision of a simple, compact and inexpensive marine tractor or detachable steering and power unit which is adapted to pull or push boats, barges, scows and the like, and particularly boats, barges, scows and the like having no power or steering apparatus; which is of a strong and rugged design in which there is achieved a maxi- ,mum power for a minimum overall size; which is of a light yet strong construction well adapted to meet the many varying conditions of actual iuse; and which lends itself to a simple, direct and economical operation productive of highly efficient and thoroughly reliable results.

The invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts as will be exemplified in the structure to be hereinafter described and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings in which is shown one of the various possible embodiments of my invention,

Figure 1 is a side elevation, partly in section, of my marine tractor, certain parts being broken away to more clearly disclose certain features of the invention,

Figure 2 is a plan view of the tractor in which certain parts are broken away to more clearly disclose certain features shown in Figure 1, and

Figure 3 is an end elevation of the tractor as seen from the left of Figures 1 and 2, certain parts being broken away to more clearly disclose certain features of the invention.

Similar reference characters refer to similar parts throughout the several view in the drawmgs.

As conducive to a clearer understanding of certain features of my invention, it may at this point be noted that in heretofore known and/or used watercraft for pulling, pushing or otherwise moving boats, barges, scows and the like, a comparatively long, and hence expensive to man and operate, vessel commonly called a tug has been used in order to carry sufficient power for traction.

One of the objects of this invention is the provision of a vessel for pulling, pushing or otherwise moving watercraft of the kind indicated which is short and compact, carrying a maximum power for a minimum overall size and which is relatively inexpensive to man and operate.

Furthermore, in heretofore known and/ or used watercraft of the sort indicated, difficulty is experienced in quickly and efliciently tying the power vessel to the boat, barge or scow to be moved or driven.

Another object is to provide a power vessel which is quickly and readily adaptable for efflcient and safe connecting or lashing with the boat to be driven.

Referring now to the drawings and more particularly to Figures 1 and 2, there is shown a hull 10 preferably rectangular in form (see Figure 2) short of length and wide of-beam which is adapted to house the various power and steering equipment of my marine tractor as will appear more fully hereinafter. In order to house a maximum of power equipment for a desired size and cost of hull, or conversely, in order to house a desired rating of power drive equipment in a minimum hull size, the hull is preferably made short and wide (see Figure 2) with squared off ends 10" and 10 straight sides 10 and 10 (see Figure 3) and a fiat bottom 10 (see Figure 1) thus achieving maximum displacement for a minimum overall size. Conveniently the bottom is slanted upwardly from the middle toward bowand stern, or given a bow and stern rake, as indicated at 10 and 10 respectively to reduce the resistance of the hull to passage through water.

illustratively, hull 10 is fashioned of a multiplicity of horizontally extending channel-iron sections 11 in parallel spaced relation with their lower edges in common planes forming a supporting framework for the bottom of the hull, as will appear more fully hereinafter.

Channel-iron sections 11 are maintained in proper spaced relation by vertical channel-iron sections 12 arranged in parallel spaced relation in illustratively four lines the two outermost or extreme lines forming the supporting framework or ribs for the sides of the hull, while the two inner or mean lines form a supporting structure for water-tight bulkheads dividing the hull transversely into three compartments (see Figure 2), all as will hereinafter more fully appear.

The upper ends of the various vertical channel-iron sections 12 terminate in a common plane substantially parallel to the mid portion of the hull bottom and serve to support the horizontal deck beams 13 in parallel spaced relation extending transversely of the hull.

To give a strong and rigid framework at minimum expense, the various horizontal and vertical channel-iron sections mentioned above are preferably fastened together in the described positions by riveting or welding in any suitable manner. Bow and stern may be additionally strengthened by diagonal braces 14 extending between deck beams 13 and bottom beams 11 of the fore and aft parts of the hull bottom to which they are conveniently welded or riveted.

The bottom, side and bow and stern channeliron ribs of the hull may be covered with steel plating 15 which is conveniently welded or riveted thereto giving a strong and rugged hull of a compact and inexpensive construction. Likewise, to the mean lines or" vertical channel-iron sections 12 may be welded or riveted steel plating 16 giving water-tight bulkheads 17 (see Figure 2) which divide the hull transversely into three watertight compartments generally indicated at A, B and C, the purpose of which will appear more fully hereinafter.

Deck beams 13 are conveniently covered with diamond pattern deck plating 18 which may be flush riveted or welded thereto giving a plane unobstructed deck surface.

Mounted above the deck on illustratively four channel-iron sections 19 19', 19 and 19 is a pilot house generally indicated at 20. The pilot house supporting channel-iron sections are fastened to suitable base sections 21 and 21 which are fastened to the deck in any suitable manner as by riveting or welding thereto. 7

Access may be had to the pilot house from the deck by way of a suitable iron ladder 22 conveniently welded to pilot house and base section 21 (see Figure 1) entrance to pilot house being made through door 20 a The height of pilot house above the deck may be established at any desired distance-it being desirable, however, that it be sufiiciently high to permit a free and unobstructed View over the barge, scow or the like being moved and yet sufficiently low to prevent excessive cost and to permit free passage under bridges and spans overits course of travel.

. My marine tractor is preferably driven by dual drive units mounted in theoutside or extreme compartments A and C of hull 10. Since, for reasons of simplicity and economy, the drive units are of like construction, only one of them will be described in detail.

Referring now to Figure 1, there is generally shown at 23 a stern tube extending through the lower part of the stern rake portion 16 of the hull and in substantial alignment with the center line of compartment A (see Figure 2) Ihe stern tube 23 conveniently of steel tubing is preferably maintained in a proper position with its axis substantially parallel to the longitudinal axis of the hull by a vertical strut 24 conveniently of steel plating, suitably cut and welded to the top of the stern tube and to the steel plating of the hull bottom 10 Additional support is given stern tube 23-by a skeg 25, conveniently of steel plating, suitably cut and welded to the bottom of the stern tube and to the plating of the bottom portion 10 of the hull preferably co-planer with strut 24.

A tail shaft 26 is suitably journaled within a stern bearing 27 mounted within the outboard end 23 of stem tube 23 and serves to transmit driving energy to a propeller 28 suitably fastened to the outboard end thereof. Tail shaft 26 is maintained in axial alignment with stern tube 23 by a suitable stool bearing 29 positioned on a chock 30 mounted within hull 10.

To prevent undue leakage of water in through stern tube 23 there is conveniently provided a brass stuffing box 31 on the inboard end 23 of he stern tube which is suitably attached to the stern tube to give a firm and water-tight connection.

Mechanical driving energy is supplied tail shaft 26; illustratively by a Diesel engine generally shown at 32 with the necessary circulating water pump, fuel oil pump, lubricating oil pump and air compressor as an integral part thereof. The Diesel engine is preferably centrally mounted within compartment A with its drive shaft 32 in axial alignment with tail shaft 26; the engine being mounted on suitable blocks and shims and conveniently bolted to the floor of the hull 10 to assure proper alignment of drive shaft and tail shaft.

For reasons of economy in construction and in reased quickness of operation, Diesel engine 32 is preferably of the one-way type thus necessitating reversing mechanism between the engine and the tail shaft to permit forward and reverse movementcf the tractor. Accordingly there is preferably provided a reversing clutch mechanism 33 suitably mounted on the floor 10 of the hull with its driven shaft 33 and its driving shaft in alignment with engine drive shaft 32 and tail shaft 26 respectively to which they are coupled by suitable mechanical coupling units 34 and 35.

Clutch mechanism 33 is thrown into forward and reverse positions conveniently by a clutch transmission lever 33 connected by a mechanical link 33; bell crank 3'7, and vertical rod 33 to a control lever pivotally mounted within pilot house 20.

Upon manipulating control lever 39, as by throwing it into the up position shown in Figure 1, rod 38 is moved downwardly causing bell crank 37 to move in a counter-clockwise direction about its pivotal support thus moving mechanical link and clutch transmission lever 33 toward the right, seen in Figure l, to effect a direct engagement between the driving engine and the tail shaft. In a similar manner a movement of control lever 39 into a down position, as seen in Figure 1, moves the clutch transmission lever 33 towards the left and effects a reverse engagement between the drive motor and the tail shaft.

Diesel engine 32 is conveniently supplied with fuel from a cylindrical tank 40 positioned within compartment A at a higher level than the fuel input connection generally shown at 32*; the tank being conveniently mounted on brackets 41 and 42 bolted to deck beams 13 in such a position that engine 32 is gravity fed with fuel from the tank by way of a supply pipe 43 taken to fuel inlet 32 of the engine as indicated above. In order to assure a free gravity feed of fuel to the engine, tank 40 is provided with a vent :4 projecting up through deck plating 18 having a return bend 44 covered with a suitable non-corrosive wire gauze. V 7

Fuel is supplied the tank by way of a supply line 45, the upper end of which is covered by a deck plate 46 (see Figure 2) maintained flush with the deck surface; conveniently deck plate 46 is screwed to the deck and is readily removable for purposes of refilling the tank.

Diesel engine 32 is supplied with compressed air from air bottles 47 and 43 suitably mounted within compartment A and connected to the air inlet of the engine by way of an air supply line 49; the air bottles are mainttained in a charged condition by an air compressor (not shown) integral with the Diesel engine.

In starting the engine, compressed air is initially obtained from an auxiliary air compressor 50 connected by way of a supply pipe 51 to air bottles 47 and 48; the air compressor being conveniently driven by a gasoline engine 52 directly coupled therewith.

Cooling water is supplied engine 32 by way of a suitable sea valve and pipe line connection (not shown) brought to the engine cooling water inlet 32 located adjacent the lower front part of the engine. The cooling water is circulated through the engine by the water pump integral therewith and is discharged through an outlet 3% in the upper rear part of the engine by way of a discharge pipe line and an outlet aft above the highest water line.

The lubricating oil system for the Diesel engine is an integral part thereof and discussion of its construction is deemed unnecessary. It may be noted, however, that the system is replenished from an oil tank 53 conveniently mounted aft in compartment A on a support 54. Oil is drawn from the tank by a spigot 55 and the tank refilled through a suitable filling line 56 taken up through the decking 13-18 and closed over with a deck plate 57 (see also Figure 2), the upper surface of which is flush with the surface of the deck.

Exhaust gases from the Diesel engine are con ducted ofi through a suitable exhaust pipe 58 which is preferably taken up through the decking 13-18 along the pilot house supporting structure l921, then up through pilot house 20 adjacent a corner thereof while it is exhausted into the atmosphere at a point slightly above the pilot house. Noise from the exhaust may be reduced by including in the exhaust line 58 a suitable muffler 59 preferably mounted within compartment A adjacent the engine. The muffler in addition to reducing the noise of the exhaust serves to impede the progress of the hot exhaust gases up through the pipe thus preventing the exhaust pipe above deck from reaching dangerously high temperatures.

In winter weather the heat from the exhaust is suflicient to warm the pilot house, and in summer, to prevent over-heating, the exhaust gases may be by-passed outside of the pilot house by a pipe connection not shown, or the exhaust line 58 may be uncoupled at elbow 58 and a straight length of exhaust pipe connected extending outside of the pilot house substituted therefor.

The power output of engine 32 is preferably controlled from the pilot house, illustratively by hand-wheel 60 connected by a suitable endless cable 61 to the throttle 32 of the engine. Thus the traction power and speed of my marine tractor, as well as its direction of motion (forward or reverse) is directly controlled from the pilot house located as above mentioned where good visibility may be had of the surrounding water. These control features are productive of many important practical advantages such as a reduction in the necessary number of operators, an increase in security and dependability of operation attendant the reduction in the human element,

and an increased quickness of manipulation due to the direct control achieved.

Electrical energy for use on board the vessel being propelled, as well as on my marine tractor, such as lighting the same, may be obtained from a generator 62 suitably mounted on the floor 10 of the hull adjacent the forward end of engine 32 and directly connected with the forward end of the drive shaft 32 thereof; electrical energy beand greater safety of operation may be obtained by making the free-board of the vessel being riven and the power driving vessel the same. This is preferably achieved (where, for example, the vessel to be driven is of a lower free-board than the driving vessel) by filling the middle water-tight compartment B (see Figures 2 and 3) with sufiicient water to lower the free-board of my powered driving vessel to correspond with that of the vessel to be driven.

Compartment B is conveniently filled with water as by opening a suitable sea valve connected by piping to the lower part or" the compartment. By proper control of the sea valve water is admitted into the water-tight compartment B, hereinafter denoted as the ballast tank, until the free-board of my tractor is reduced to correspond to that of the vessel to be driven.

Where it is found desirable to increase the freeboard of the tractor, water ballast is removed from tank B. Accordingly there is provided a pump 63 suitably mounted on a chock 64 positioned in compartment A at the forward end of engine 32 connected by a suitable inlet pipe 65 to the lower portion of the ballast tank B and by a discharge pipe 66 to a suitable discharge port provided in the hull at a point above the highest water line.

Operation of pump 63 is conveniently achieved by coupling it with Diesel engine 32. Illustratively there is provided a suitable gear wheel 67 mounted on engine shaft 32 adjacent the forward end thereof, which engages a gear wheel 68 suitably mounted to one end of clutch mechanism 69, the other end of which is directly connected to the pump. Pump 63 is put into operation to discharge the water in ballast tank B by throwing in clutch 69 as by manipulating clutch lever 69 and completing the mechanical engagement between the pump and engine 32. As the water is removed from the ballast tank the free-board of the vessel is increased until the proper height is reached at which the pump is cut off by throwing out the clutch 69 and thus severing the mechanical drive connection between the Diesel engine and the pump.

It may at this point be noted that the various parts of my driving and pumping units, such as the Diesel engine 32, clutch 33, fuel tank 40, air bottles 47 and 48, generator 62, pump 63 and clutch 69 are preferably distributed along the length of compartment A so as to give a balanced weight fore and aft and preserve a level deck.

Entrance is had to the engine rooms A and C by way of manholes '71 and '72 (see Figure 2) provided in the deck, and ladders '73 and '74 respectively cooperating therewith being suitably fastened to water-tight bulkhead 17. Ventilation of compartments A and C is effectively achieved by suitable ventilators 125 and 126 adjustably mounted in decking 13--18 in unobstructing positions adjacent pilot house base sections 21 and 21 respectively. Access to ballast tank B, for purposes of cleaning, repairing and the like, is had through manholes and 76 in opposite ends of the deck.

Free travel between compartments A and C is provided for by a passageway D extending transversely of ballast tank B. The side walls of the passageway are of steel plating welded or riveted t0 Water-tight bulkheads 17. The top is of similar steel plating conveniently welded or riveted to bulkheads and side walls and is suitably arched to stiffen the side walls of compartment B and strengthen the walls of the passageway. The passageway is arched at bottom above the floor 10 of the hull to provide an unobstructed walk between compartments.

It will be noted that the arched passageway allows water to pass unobstructed above and below it. Thus there is assured an equalization of the level of water in the tank from end to end.

While but a single driving unit and ballast tank pumping unit has been described in detail, it will be understood in view of what has been said above that similar units are positioned in compartment C and similarly controlled from the pilot house 20.

Referring to Figure 3 there is shown positioned in compartment C a Diesel engine 78 of identical construction (although preferably of opposite rotation) to the Diesel engine 32 mounted in compartment A. Fuel may be suppplied engine 78 by a fuel tank 79 suitably mounted in compartment C in a position and manner of mounting fuel tank 40 in compartment A; the fuel being fed by gravity to the engine by way of supply pipe 80. Air is supplied the engine from air bottles 8l82 positioned within the compartment adjacent water-tight bulkhead 17 and connected to the motor by a suitable air line 83.

The air bottles may be charged by the built-in air compressors of either or both of the Diesel engines 32 or '78 from the auxiliary air compressors 5852 positioned, as described above, in compartment A, all as will more fully appear hereinafter.

For reasons of dependability and safety of control of my marine tractor, fuel supply tanks 40 and 79 and their associated gravity feed pipes 43 and 80 respectively are interconnected by way of pipe 84 taken along passageway D through ballast tank 5.

Diesel engines 32 and 78 are supplied with fuel from tanks 40 and '79 by way of the fuel supply line 43-80-84 through the individual branch lines 43 and 80 respectively. Suitable valves 85, 86, 87 and 88 are respectively located in pipe lines 43, 43 80 and 80 of the fuel supply line so that either or both engines may be supplied with fuel from either or both of the fuel tanks.

Thus, for example, the single engine 32 may be supplied with fuel from the single tank 40 by closing valves 87 and 88 located respectively in the fuel supply pipe line 80 from tank 79, and the individual line 80 to the engine 78 and opening valves 85 and 86 respectively located in the fuel supply line 43 from tank 40 and the individual line 43 to the engine 32. A direct flow of fuel is then provided engine 32 from tank '40 by way of supply line 43, valve 85, individual line 43 and valve 86.

Upon opening valve 87 in the fuel supply line 80 from tank '79, Diesel engine 32 may be supplied with fuel from both tanks, the flow of fuel from tank '79 being by way of supply line 89, valve 87, interconnecting pipe 84, individual supply pipe 43 and valve 88 to the engine.

Engine 32 may be supplied with fuel from the single tank '79 by closing valve 85, the flow of fuel from the tank to the engine being along the above described path.

Both of the Diesel engines may be supplied with fuel from a single tank, for example, tank 49 by opening valves 96 and 88 in their respective individual supply lines 43 and 89 closing valve 87 in the supply line 80 from tank 79, and opening valve 85 in the supply line 43 from tank 40, the flow of fuel from the tank to the engines being by way of supply pipe line 43, valve 85 (and individual supply line 43 and valve 86 to engine 32), interconnecting pipe line 84. individual supply line 80 and valve 88 to the engine '78.

For normal operation, however, both engines are supplied from both tanks, all the valves 85, 86, 87 and 88 being in the open position.

Likewise for reasons of flexibility and general dependability of control, air bottles 47-48 and 8l82 and their respective associated air lines 49 and 83 which supply compressed air to engines 32 and 78 are interconnected by an air line 89. Either or both of the Diesel engines 32 and '78 may be supplied with compressed air from either or both of the air bottles 47-48 and 8l--82 by proper manipulation of valves 99, 91, 92 and 93 respectively included in the air supply line 49 from air bottles 4748, the individual branch line 49 to engine 32, the air supply line 83 from air bottles 8l82, and the branch air line 83 to engine '78.

Thus, for example, the single engine 32 may be supplied with compressed air from either of air bottles 4748 or 81-82 by opening valve 91 to the engine 32, closing valve 93 to engine 78, and opening either of the valves 90 or 92 in the respective air lines ill-83 connected with air bottles 4'748 and 8182; engine 32 may be supplied with compressed air from both of these air bottles by opening both of the valves 90 and 92.

Similarly both of the engines may be supplied with compressed air from either of the air bottles by opening valves 91 and 93 and opening one of valves 90 or 92 and closing the other one thus establishing (for an assumed open position of valve 90 and a closed position of valve 92) a supply of compressed air from air bottles 47-48 by way of air line 49, valve 90 (and valve 91 and individual air line 49 to the engine 32), interconnecting pipe line 89, valve 93 and individual air line section 83 to engine 78; both engines may be supplied with compressed air from both pairs of air bottles by opening all of the valves 90, 91, 92 and 93.

To further the flexibility of engine operation and control, either or both pairs of air bottles may be charged from either or both of the air compressors built into the Diesel engines. There is provided an air line section 94 from the air compressor of engine 32 which is interconnected by section 95 with an air line section 96 taken from the. air compressor of engine '78. From air line section 94 there is taken a branch line 94 to charge air bottles 47--48, and similarly from section 96 there is taken a branch 96 to supply air bottles 8l-82. V

In order that the above-mentioned control may be achieved, there are provided in the respective air line sections 94, 94, 96 and 96 the air valves 97, 98, 99 and 100 which may be individually operated to cut on or shut off the flow of air in the air line sections in which they are respectively included. Thus, either of air bottles 4'7-48 or 81-82 may be charged from the air compressor associated with the single Diesel engine 32 by closing the valve 100 associated with the air compressor of engine 78, opening the air valve 97 in the air line leading to the air compressor associated with engine 32, and opening either one of lbU valves 98 or 99 and closing the other to establish connection to either of the air bottles; both air bottles may be charged from the single air compressor.

In a similar fashion either of the air bottles may be charged from the air compressors of either Diesel engines by opening valves 97 and 100 included in air line 94-95-96 and opening either one of valves 98 or 99 while maintaining the other one closed; both air bottles may be charged from the air compressors associated with both of the engines.

In order that the air bottles may be charged when the Diesel engines are at rest so that compressed air may be obtained to initially start the engines, there is provided, as mentioned above, an air compressor 50-52 connected by way of an air pipe 51 and a suitable valve 101 to air line 9495-96. Either or both of the air bottles 47-48 or 81-82 may be initially charged by closing valves and 92 in the supply air lines 49 and 83 to the Diesel engines, closing valves 97 and in air lines 94 and 96 from the air compressors associated with each of the engines, opening valves 101 in air line 51 from the auxiliary compressor, and opening either one or both of the valves 98 and 99 in air line sections 94 and 96 respectively leading to air bottles 4748 and 8182.

Thus, in a simple and economical manner, there is assured a high efficiency and thorough reliability of operation of my tractor throughout the various load conditions met with in actual use and in spite of possible breakdown and/or shutdown for purposes of inspection and repair.

To give a full control of the free-board of my marine tractor, there is provided in compartment C a discharge pump 102 of similar construction to the discharge pump 63 positioned in compartment A and adapted to be driven by the engine 78 in a manner similar to the driving of pump 63 by engine 32, all as more particularly described above.

Discharge pump 102, like pump 63, has an input pump line 103 taken to ballast tank B. Conveniently input lines 103 and 65 leading respectively to pumps 102 and 63 join a common pipe 104 suitably connected to the pipe 77 interconnecting the parts of ballast tank B separated by passageway D as more particularly set forth above. Suitable valves 105 and 106 are included in intake pump lines 65 and 103 respectively, thus permitting a withdrawal of the water ballast in tank B by either or both of the discharge pumps.

Thus, where both Diesel engines are running either or both of the discharge pumps 63 and 102 may be actuated by throwing in suitable clutch mechanism mechanically connecting the pumps with their associated Diesel engines, the nature of which is more particularly described above in connection with the discussion of the operation of pump 63.

Where but a single pump is being operated, illustratively pump 63, one of the intake pump line valves, illustratively 106, is closed while the other, 105, is opened. Water ballast is removed from tank B through communicating pipe 77 up through the intake pipe 104, valve 105, intake pipe 65, pump 63 and is discharged out through the discharge pipe 66.

Where both of the pumps are being operated to quickly discharge ballast tank B in order to rapidly raise the free-board of the tractor, both of the intake pump valves 105 and 106 are maintained in open position and the water drawn up through the common intake pipe 104 is divided, part passing out, as mentioned above, through intake pipe 65, pump 63 and discharge pipe 66, and the remainder passing through valve 106, intake pipe 103, pump 102 and then discharged through pipe 107 above the highest contemplated water line.

As mentioned above the free-board of my tractor is decreased by filling the ballast tank with Water as by opening a sea valve and running water in through an intake pipe 70 directly connected with the ballast tank. It will be understood, however, that where it is found desirable to hasten the decrease in the free-board, an additional intake pipe with its associated sea valve may be connected to the ballast tank.

My tractor powered and controlled as above described may be steered by two rudders generally shown at 108 and 109 (see Figure 2) suitably mounted at the stern of hull 10 and controlled from pilot house 20, as will hereinafter more fully appear.

For rudder 108 a rudder plate 110 conveniently of thick steel plating suitably shaped is balanced and mounted in the vertical stock 111 to which it is conveniently welded. A carrier 112 suitably journaled in rudder port 113 serves to support stock 111 and its associated rudder plate 110; the rudder port being conveniently fashioned of steel piping bushed at each end with brass bushings thus forming a supporting bearing and a suitable stuffing box. The position of rudder plate 110 is controlled by a suitable tiller 114 keyed to stock 111 associated with the rudder plate of rudder 108.

The rudder 109, preferably of similar construc tion, is similarly controlled in movement by a suitable tiller 115 (see Figure 2).

In order to assure like settings of rudders 108 and 109, the tillers 114 and 115 respectively associated therewith are linked together by a rod 116 suitably fastened to the ends thereof. To tillers 114 and 115 is connected the opposite ends 117* and 117 of the steel cable 117, a mid portion of which (see Figure 1) is coiled about and secured to hub 118 of steering wheel 118 mounted in pilot house 20.

In order that a maximum steering efficiency may be had the steering cable 117 is guided by suitable sheaves 119 and 120 (see Figure 2) properly positioned and suitably mounted to sides 10 and 10 of the hull to exert steering forces on tillers 114 and 115 substantially tangential to their arcs of travel.

Protection for steering cable 117 above deck and prevention of unnecessary obstruction of free movement about the deck is achieved by guiding the steering cable through decking 1318 adjacent the fore channel-iron sections 19 and 19 supporting the pilot house (see also Figures 1 and 3) by sheaves 121 and 122 properly positioned and suitably mounted on the ceilings of compartments A and C; the upper part of the steering cable being guided by sheaves 123 and 124 (see Figure 3) suitably positioned in the pilot house.

My marine tractor is provided with suitable deck fittings such as cleats 127 mounted on decking 1318 at suitable positions adjacent the sides of the vessel and bits 128 cooperating therewith to permit tying or lashing to a vessel to be moved. As a safety measure side rails 129 are provided comprising a flexible cable 130 looped through portable stanchions 131 removably fitted in sockets 132 secured to the deck plate 18 in proper spaced relation alongthe sides of the vessel; the deck fore and aft being without railing to permit free access to bits 128 and their associated cleats.

The tractor is provided with necessary running lights and a suitable air whistle 133 for signalling purposes. The air whistle is connected byway of an air line 134 to the air supply line 4.-98983 from air bottles 17-48 and 8182 (see Figure 3); a suitable control valve 135 for the whistle (see Figure 1) being provided in the pilot house.

It will thus be seen that there has been provided in this invention a watercraft in which the various objects hereinbefore noted, together with many thoroughly practical advantages are successfully achieved. It will be seen that the craft is strong and rugged in construction, that it is short and compact carrying a maximum of power drive equipment for a minimum of length, and that it is well adapted to meet the many varying conditions of actual practical use. Furthermore, the square ended bow of the tractor and the direct control of the height of freeboard permits the tractor by an abutting engagement with a square ended stern of a boat or barge to steer as well as push such boat or scow.

As many possible embodiments may be made of the above invention, and as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. In watercraft of the character described, in combination, a hull having a plurality of fore and aft water-tight bulkheads therein forming a tank with the bottom and end walls thereof, driving motors positioned within said hull on opposite sides of said tank, a water-tight passage extending through said tank giving communication between the driving motor compartments of said hull, and means operable by said motors for filling and emptying said tank.

2. A marine tractor for pushing and guiding a watercraft comprising, in combination, a hull having a flat bow adapted to contact a watercraft, a driving power unit mounted within the hull, ballast means located in the hull and operated by the power unit for raising or lowering the hull to bring the flat bow into contact with a portion of the watercraft which is suitable to receive a pushing force from the bow, a pilot house supported by and extending above the deck of the hull, and means located in the pilot house for controlling the operation of the power unit to drive the hull and to raise or lower its bow, whereby a marine tractor is provided for pushing watercrafts of variable freeboard levels.

3. A marine tractor adapted to push a watercraft comprising, in combination, a hull having a bow adapted to contact a watercraft, a driving power unit mounted within said hull, ballast means for raising or lowering the hull to bring the bow into contact with such portion of a watercraft as is suitable to receive a pushing 105 force from the bow of the tractor, and means located above the deck of the hull for controlling the power driving unit and the ballast means, whereby a marine tractor is provided for pushing watercrafts of variable freeboard levels.

EADS JOHNSON.

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