US429468A - Steam tow-boat - Google Patents

Description

(No Model.) 4 Sheets-Sheet .1.

A. McDOUGALL STEAM TOW BOAT J w MN. 01 \wwr W M/ 00 v I m m 3 x a W M m, n u N b .J w 4 w W w b M N q m/tweooao J 6% W MM RI Tans cu, PNOTO-LITNO.,VIASHINGYON n c (No Model.) 4 SheetsSheet 2.

A. MODOUG'ALL. STEAM TOW BOIAT.

No. 429,468. I Patented June 3, 1890.

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(No Model.) I 4 Sheets-Sheet 3.

' A. MODOUGALL.

STEAM'TOW BOAT.

No. 429,468. Patented June 3,1890.

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(No Model.) 4 SheetsSheet 4. I A. MODOUGALL. STEAM TOW BOAT.

No. 429,468. PatentedJune 3,1890.

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UNrTED STATES PATENT OFFICE.

ALEXANDER MCDOUGALL, OF DULUTH, MINNESOTA, ASSIGNOR TO THE AMERICAN STEEL BARGE COMPANY, OF NEIV YORK.

STEAM TOW-BOAT.

SPECIFICATION forming part of Letters Patent No. 429,468, dated June 3, 1890.

Application filed September 20, 1889. Serial No. 324,496. (No model.)

To all whom it may concern.-

Be it known that I, ALEXANDER McDoU- GALL, a citizen of the United States, residing at Duluth, in the county of St. Louis and State of Minnesota, have invented a new and Improved Steam Tow-Boat; andI do hereby declare that the following is a full and exact description of the same.

I have described and illustrated in several Letters Patent of the United States granted to me on May 24:, 1881, No. 241,813; on June 20, 1882, No. 259,889, and on December 4, 1888, No. 298,997, and in application for Letters Patent filed May 24, 1889, and numbered serially 311,991, various new and useful improvements in the construction and form of hull for tow-boats and embodying in each the same general characteristicsviz., a metallic water-tight hull having a curved closed top and adapted to be almost wholly submerged.

WVhat I propose in the present application is the adaptation to steam tow-boats of a hull having the general characteristics above mentioned, but with certain changes in form and construction from any of the hulls described in said Letters Patent and application, as will adapt it more particularly to steam tow-boats, so that the tow-boat will carry its own power and will be capable of towing other vessels. What I alsopropose in the present application is the employment of several new and useful features With such a hull," as will be more fully hereinafter described and claimed. WVhat I further propose in this application is to describe and claim several very important and advantageous features appertaining to said hulls, whereby the pitching and rolling of the bull in heavy seas is greatly reduced, thereby making the hull specially adapted to steam tow-boats for the reason that under all ordinary conditions the propeller will be kept in the water. I propose to have this steam tow-boat adapted for towing other vessels, more particularly those vessels described in the above-mentioned Letters Patent and application, or adapted for carrying freight or for carrying freight and also for towing other vessels.

To this end my invention consists of a steam tow-boat comprising the elements to be more particularly described and claimed hereinafter, and which are illustrated in the accompanying drawings, forming a part of this application, and to which attention is invited for a better comprehension of my invention.

In the drawings, Figure 1 is a side elevation of a steam tow-boat especially adapted for towing-other vessels and for carrying freight; Fig. 2, a longitudinal sectional view of the same; Fig. 3, 'a side sectionalview of Fig. 1, taken about midships and looking aft; Figs. 4 and 5, diagrammatical views of the hull of an ordinary steam tow-boat, illustrating its different movements in pitching; Figs. 6 and 7 diagrammatical views of a hull of my design under similar conditions; Figs. 8 and 9, diagrammatical cross-sectional views of the hull of an ordinary steam tow-boat, illustrating, its differentmovements in rolling; and Figs. 10

and 11 diagrammatical cross-sectional views" of a hull of my design under similar conditions.

In all of the above Views corresponding parts are designated by identical letters of reference.

A represents the hull, and a the bow and b the stern of the same. This hull is made, preferably, of iron or steel plates and is constructed, by preference, in the manner described in my above-mentioned application for Letters Patent, though it will be evident that any other approved method of construction may be adopted. The sides of this hull, except at the bow and stern portions, are perfectly parallel, both horizontally and vertically, and the bottom thereof is preferably nearly flat, with rounded corners merging into the sides. Instead of making the bottom of the hull nearly fiat, it might be made curved or ellipsoidal, or it might be made angular in cross-section. The top or upper deck of the hull is curved, with an elevation at its center of about thirty-five degrees or thereabout, and springs in and up from the side at ornear the low-water line. From the extreme bow to the extreme stern this top or upper deck extends on a perfectly straight horizontal line, so that the hull is therefore without sheer. By doing this I am enabled to make the frames and plates much easier and in less time and at the same time much stronger than can be done with hulls having a sheer. This feature, however, of the hull-via, a top extending on a perfectly horizontalline and the advantages arising therefrom are very clearly and fully described in my said application. The bow of the present hull is spoon-shaped, but differs from the bows of my former boats in being materiallylonger and more pointed and with finer lines, so as to enter the water very easily. The shape in cross-section of the hull at the bow portion changes gradually from that of an oval at the rear portion of the bow to that of a circle at the extreme forward end, the change being brought about by a gradual change of the upper deck from a flattened arch toa perfect semicircle by a gradual upward curve of the bottom and by a gradual inward curve of the sides. The stern b is also made spoonshaped and is built on practically the same lines as the bow. The stern, however, is provided with a skeg 0, covered with the metallic plating of the vessel and forming a part of the hull. The lower end of this skeg is in line with the bottom of the boat and extends out to a point some distance from the extreme rear end of the hull, so as to leave an over hanging portion.

hen the boat is normally loaded, the extreme ends of both the bow and stern should be very near the surface of the water, so that in pitching the waves can ride up on the bow and stern, for the reason explained hereinafter.

A usual rudder (Z is mounted on the rear end of the skeg and is operated by any suitable mechanism from the pilot-house, the location of which will be more fully pointed out hereinafter.

B represents a boiler, and (J an engine of any suitable construction placed within the hull.

For convenience, and in order that all machinery may be out of the way of the cargo, Iplace both the boiler and engine near the stern of the boat. The usual coal-bunkers are placed near the boiler and preferably surround it.

The engine 0 connects in the usual way with and operates the shaft D, carrying the propeller E. This propeller rotates directly in the rear of the skeg c and direct-1y in advan cc of the rudder (Z. A suitable packingbox f is placed within the skeg, so as to surround the shaft and exclude water.

A suitable dome or dead light g, secured to the upper deck, gives light to the boiler and engine.

Extending up from the upper deck and communicating with the interior of the hull are a number of hollow metallic cylindrical turrets F, G, and H. These turrets are preferably fastened in position by means of a heavy angle-iron passing entirely around the bottom of the turret and riveted to the turret and also to the curved deck. The end turrets F and H each contain a staircase or steps,

whereby entrance is given to the hull and its dilferent compartments from the cabin, and the central turret G incloses the smoke-stack h of the boiler. By thus ineasing the smokestack it is effectively protected from the action of the waves thereon.

Sec'u rely fastened on top of these turrets F, G, and H is a cabin I, of any suitable and attractive design and construction. This cabin is further supported 011 each side by means of smaller pipes k 71:, secured to the upper deck and to the bottom of the cabin by any suitable means, so that the cabin will be held very rigidly in position.

At the forward portion of the cabin is the pilot or wheel house J, Within which is placed the steering-wheel for controlling the rudder.

Near the forward portion of the hull is another turret K, secured in place similarly to the other turrets, and supporting a workingdeck L. On this working-deck is a usual capstan or windlass for handling the anchorchains, the.

The arrangement of compartments within the hull and the interior construction and rooms with-in the cabin are unimportant and irrelevant to my invention.

Suitable hatches ZZZ Z are removably secured in place on the upper deck, preferably by means of ordinary SCl6W-bOllIS,tS shown in Letters Patent No. 393,997, before mentioned, so as to be readily removed and replaced.

Life-lines m m m m extend. from bow to stern, so as to oilfer protection to the crew in severe weather. \Vhen the vessel is being loaded, these life-lines are to be removed, so as not to interfere with the usual loading apparatus, and when desired they can be easily set up again.

By means of the construction above described I am enabled to produce a steam towboat with a considerable freight-carrying capacity, and which will be capable of great speed by reason of its form of hull. Moreover, the cabin, by being practically disconnected from the hull, will be always cool and airy, and entirely free from the objectionable odors which are inseparable from interior cabins.

Further, by means of the general form of hull I have adopted, I am enabled to make a vessel peculiarly adapted for a steam towboat, for the reason that the tendency to pitch and roll in heavy seas is greatly reduced, and the propeller will be always kept under water. This can be better understood by reference to Figs. 4, 5, 6, 7 8, 0, l0, and 11 of the drawings, in which :1; represents the hull of an ordinary towing-steamer, such as are seen 011 the great lakes of this country, and 3 represents a hull of my general design. In all of these views,

1 2 represent the load water-line of each boat, and 0 represents the center of gravity of each boat.

I11 Fig. 4 the effect of the sea has been to move the boat on, so as to bury the bow under ITO water and elevate the stern entirely out of water, and thereby cause the propeller to race,

much to the detriment of the machinery. The

, vessel in rolling when moving at right angles boat is therefore thrown out of its balance and the wedge-shaped air-space 0 u s is submerged and is exerting a powerful pressure upwardly,while the wedge portion 0 r r is out of the water and is exercising a powerful down ward pressure by its weight. forces, Working together, tend to bring the boat back to its balance, but by reason of the momentum acquired and by the help of the action of the sea the center of gravity is passed, the reverse action takes place, and the vessel is thrown in the position seen in Fig. 5. Here the after air-space 0 t a is submerged and exerts an upward pressure. The

bow portion 0 s q is elevated and exerts a downward pressure. Once more the boat moves toward its line of balance, but by reason of the momentum and the action of the waves the center. of gravity is passed and the original position regained. The oscillating motion of the hull often continues long after the disturbing influence of the waves has ceased.

From an inspection of Figs. 6 and 7 it will be seen that the action of the sea on boats of my design is entirely different from the action of the sea on ordinary vessels. wave broaches a vessel of my design, the hull is thrown in the position shown in Figs. 6 and 7, with the bow slightly depressed and the stern slightly elevated, or vice versa. The water meeting with but little resistance now begins to climb up on the bow or stern, as the case maybe, and exerts by its weight a downward force, opposing the upward pressure of the submerged portion. The powerful upward pressure caused by the submerged portion is thus eliminated by reason of the opposing force caused by the weight of the water on the submerged portion, and the hull regains its equilibrium solely by reason of the much less powerful force caused by the elevated portion of the hull. There is therefore but very little momentum acquired, and I have found by practical experience that the movement of the hull toward its line of balance is very slow and that the movement. of the hull beyond the line of balance is Very slight. The oscillating motion of the vessel after the eifect of the waves has ceased is thus almost entirely overcome, while the oscillat- These two As'soon as a of water, so as to allow the waves to roll up on the ends, as above mentioned.

The extreme movements of an ordinary to the direction of the sea are shown in Figs. 8 and 9. It will be observed that the first effect of the sea is to rise up the side and force the hull obliquely over, so as to assume the position shownin Fig. 8. Here an airspace 0 tu on one side is submerged and is exerting an upward pressure, and a space 01;

s on the other side is elevated out of-the moves past the line of balance and assumes the position shown in Fig. 9. The reversed motion now takes place, so that the boat continues to oscillate from side to side, precisely in the same manner as when pitching and on exactly the same theory. The movements of the vessel in rolling, however, are much greater than when pitching, from the fact that the Width is much less than the length, and therefore offers less resistance to the water in moving and from the additional fact that there is a greater space exposed to the action of the wind and waves.

It often happens that an ordinary vessel whose course may lie at right angles with the direction of the waves is often compelled to run bow on to the sea by reason of the excessive rolling and the liability of waves breaking over the bulwarks and sinking the vessel, so that much time is not only lost,but the vessel may be carried many miles out of her original course.

The effect of a side sea on a vessel of my design is entirely diiferent from 'that on an ordinary vessel. From an inspection of Figs. 10 and 11 it will be evident that a wave in striking a hull of my design from the side will strike a glancing blow and will roll up on the rounded top a portion of the way toward the center. The first effect of the sea in striking the vessel might be to careen the vessel slightly to one side or to move the hull bodily to one side; but any rolling movement of the hull must necessarily be very slight by reason of the low-curved surface exposed to the waves and wind and the glancing character of the blow of the waves thereon. Any rolling, movement to one side which might be caused by the action of the waves is immediately counteracted by the weight of a wave on the curved side of the hull exposed to the 'waves and by the friction and weight of the wave and sliding back. It might be supposed by reason of the extremely high-load line and the small amount of hull exposed above the water that heavy seas striking the boat from the side would roll entirely over the vessel;

but this is not the case, for I have foundby practical experience that in the severest storms the waves generally roll only a short distance up on the curved top, and then having apparentlylost their force and power roll immediately oif the deck; and I have found from a practical experience in storms of such severity that ordinary boats would be compelled to turn bow on to the waves that aboat of my design can move even at right angles to the direction of the sea without more than a thin layer of water passing over the curved de'ck. It will therefore be seen that I greatly reduce the pitching and rolling of the hull, and the boat is thereby rendered specially applicable for the purposeintended, and that the form of hull, while being of the strongest possible torm reduces all superstructure to the minimum.

ALEXANDER MODOUGAIJJ.

\Vitnesses:

FRANK L. DYER, CHAS. R. HAINEs.

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