REGISTER OF PENNSYLVANIA. DEVOTED TO THE PRESERVATION OF EVERY KIND OF USEFUL INFORMATION RESPECTING THE STATE. EDITED BY SAMUEL HAZARD. VOL. XIII.-NO. 2. PHILADELPHIA, JANUARY 11, 1834. NO. 314 From the Journal of the Franklin Institute. CHESAPEAKE AND DELAWARE CANAL. EXPERIMENTS BY STEAM BOATS. Experiments made on the Navigation of the Chesapeake and Delaware Canal by Steam, reported by A. D. BACHE, Professor of Natural Philosophy and Chemistry in the University of Pennsylvania. the stroke of 80 lbs. per square inch, an estimate probably not far from the truth if the pressure within the boiler was correctly stated, and supposing thirty-five double strokes to be made in a minute, the power boiler was a vertical cylinder, six feet in length, and would be more than double the nominal amount. The and twenty draught tubes from an inch and a half to three feet in interior diameter, containing one hundred two inches in diameter, and thirty inches in length, the The great importance of applying steam to naviga, tubes uniting above in a wide chimney. It appeared tion upon canals, has not failed to strike those interest- by the experiments that this boiler was competent to ed in that mode of internal communication. It has been keep up a supply of steam for about thirty-five double denied that steam navigation is possible in canals, when strokes of the engine per minute. The paddle wheels injury to the Banks is not guarded against by expensive were placed at the sides of the boat, and between oneprecautions; and that it can be advantageously applied third and one-half of the length of the boat from the in any case is still doubted, notwithstanding the attempt bow; the wheels were eight feet two inches in exterior in Great Britain which is reported to have been success-diameter, and four and a half feet wide; the buckets ful. The result of experiments made on the Chesapeake and Delaware Canal, seem to me to go far to remove, entirely, such doubts in relation to the larger class of canals; and with this impression, I have suppos. ed that a report of them might prove interesting. In the experiments of which I am about to give an account, I assisted, without directing; all that is set down as coming from myself was obtained by careful observation, and when the information has been received from others, the authorities upon which it rests are also given. I engaged in these experiments with a view to their bearing upon an interesting inquiry in practical science, and the materials are so laid before the reader that he may have a test of the accuracy of the observations, and of the conclusions which may be drawn from them. were six inches deep, and made of cast iron. The weight of the boiler was stated to be 2214 lbs., and of the wheels about one ton. The preliminary trials with the boat were made on the river Schuylkill; upon them, as they were not made in the precise circumstances in which the boat would have to work in the canal, not much stress was to be laid; they were so far satisfactory, however, as to speed, and to the slight apparent swell produced by the boat at the highest speed of which the engine was capable, as to induce the President of the Canal Company to have the boat sent to the Chesapeake and Delaware Canal for further trial. A summary of the results obtained in a trip from the upper ferry to Gray's ferry, and back again, and in several short trips from near the middle ferry to near Gray's ferry, is given below. The aveA canal boat which had originally plied upon the rages being deducted from different numbers of expeSchuylkill, and been noted as a quick boat, was alter-riments are not entirely comparable, but are probably ed, under the direction of the President of the Chesa- as close approximations as the nature of the other data peake and Delaware Canal Company, (Robert M. Lew. will furnish; the distances were measured from Allen's is, Esq.) so as to increase the length, and to give great- map of Philadelphia, and having been thus obtained, er sharpness to the bow, as well as to reduce the bot- can only be considered as approximations. tom to a regular and gently swelling curved surface, from the stem and stern, without any internal flexures. The length of the boat was thus made eighty feet, the length of the false bow, in the direction of the axis of the boat, being seven and a half feet; the width of the boat was ten feet; the draught, when light, twelve inches, and with a load of forty tons, fourteen inches, exclusive of the keel. The alterations were made under the direction of Mr. James Rush, of the firm of Rush & Muhlenburgh, and the engine, paddle wheels, &c. put in under his charge; from him I obtained the details just given, and those which follow, in relation to the boat and engine. it The engine was the result of an exchange, which enabled the experiment to be made with economy; proved, however, to be much too small for the purpos: es in view. The diameter of the cylinder was eight and a half inches, and the length of stroke two and a half feet, the pressure of the steam with which it was sup. plied was about 140lbs.; 150lbs. to the square inch, on the safety valve, being the maximum pressure. The steam was cut off at half stroke, and the escape steam served to heat, in part, the water which was thrown into the boiler. The nominal power of the engine was ten horses; but with a mean effective pressure, during VOL. XIIL 3 The tide was running down, and near the last of the ebb, the wind was from the S. E., and therefore, in part, favorable in those trips in which the tide was adverse. Greatest speed down stream, 8.45 miles per hour. Least do. do. 6.50 do. Steam stopped off to pass under the middle ferry bridge. Least 6.88 Average speed down stream 7.37 do. minute, Least do. up stream do. do. Mean 7.12. paddle wheels per do. Smil's per ho Average ratio of the velocity of the boat 39 I have thought it best to give these conclusions, since they are sufficiently correct to afford a tolerable comparison with the inferences from similar experiments on the canal, and thus to enable the results for a stream to be compared with those in the comparatively narrow and shallow canal. In the annexed statement, six columns are devoted to In the experiments on the Chesapeake and Delaware the record of experiments, and to the results of calcucanal, circumstances were much more favourable to accuracy, and greater interest attaching to the observa- lations; the first column gives the points at which the tions, greater pains were taken to insure it. The marks observations were made; the second, third, and fourth, upon the tow path were referred to as affording points the time of observation; the fifth, the number of revoat known, or easily ascertained, distances apart, and by lutions of the paddle wheel per minute; and the sixth, a subsequent comparison of these with the correspond-general remarks. In the seventh column are the ing measures in the channel of the canal, as afforded by breadths of the canal at the several points of observathe survey of the work, where it is not straight, the tion; in the eighth, the actual distances gone over, obtrue distances were found. The time being observed tained as already described; in the eighth and ninth the by myself, with a watch with a second hand, was re- time occupied in passing over the distances; in the tenth corded by a friend who entered upon the notes any oth- the rate of travel per hour, and in the eleventh the relaer observations which it was deemed necessary to pre- tive velocity of the boat to that of the periphery of serve. In these experiments, although pains were ta- the wheel, the velocity of the latter being taken as ken to ascertain the speed of the boat and the capabili- unity. The actual depths of the sheet of water at the ties of the engine, yet the main interest attached to the several points of observation, to correspond with the observation of the disturbance produced upon the breadths given in the seventh column, would not have banks at different degrees of speed, and to determin- been taken in any surveys of the canal yet made. The ing the effect of the figure of the boat, and the combin- widths of the canal are approximations, only; they were ed action of the boat and of the wheels, upon the wa taken from a map of the survey of the canal. ter; the power of the engine could easily be increased Journal of the Experiments on the Navigation of the within reasonable limits, provided the effect was not Chesapeake and Delaware Canal by the Steamboat such, with the less power, as to produce a very great Lewis, September 22d, 1833. wash of the banks. To any one who has witnessed the labour with which the rapid travelling upon this canal in barges towed by horses is accomplished, and the violent effects upon the banks produced by the great swell raised, a desire to substitute some less painful and less destructive method of navigation can hardly fail to oc FIRST EXPERIMENT. The steamboat towing one of the barges, for passengers, used upon the canal. Length of barge 90 feet, breadth of beam 19 feet, draught, when light, 23 inches, including the keel, which is 11 inches; draught with the ordinary number of passengers 33 inches. Awning of the barge up. The barge 15 feet in rear of the steamboat. Twenty-eight persons in the steamboat; seven in the barge. SECOND EXPERIMENT, (continued.) After passing mile post No. 6, a sloop was attached by tow lines to the steamboat; the burthen of the sloop was forty-four tons, the actual loads being fifty tons of anthracite, and the draught sixty-two inches exclusive of the keel. The helmsman of both the steamboat and the sloop, not understanding the management of their respective vessels, in the new circumstances in which they were placed, there was so much sheering in one direction and another, that it was deemed expedi ent to cast off the tow lines on the approach of the passenger barge which appeared in sight. The speed was estimated differently at from three to four miles per hour, but the checks which it constantly met with rendered any accuracy of estimate out of the question. The passenger barge,towed by eleven horses, now passed, and the steamboat followed; part of the experiment, which follows, was made in the shallower end of a former mill-pond, and the other through.about onequarter of a mile of the deep cut. Mean velocity of steamboat, wind in favour 7.85 miles per hour. 2 Relative rates. Mean, 39 7.43 7.64 S 1.055 to 1. O Relative rates. Steamboat towing a freight barge of twenty-five tons burthen, loaded with from fifteen to eighteen tons of merchandise, and drawing two and a half feet of water. Wind very light, in favour of the boat. The passenger barge from the west appearing in sight, the freight barge was disengaged, and the boat put about. At the first part of this experiment there was a difficulty encountered similar to that noticed in the case of the attempt to tow the sloop, but less in degree; it resulted from the inexperience of the helmsman of the barge, and as soon as he had been directed how to steer, and followed the directions, there was no further trouble from this source. FOURTH EXPERIMENT. The wave from the bow of the boat, owing to the peculiar form of that part, fell in with the wheels, and was Steamboat alone, returning in rear of the passenger disposed of by them; while the lean form of the stern barge drawn by seven horses. Light wind ahead. brought together the waves produced by the wheels, which, therefore, spread very little, if at all, in a later. al direction, that is, towards the banks, being directed towards the tow-path only in parts of the curved portions of the canal. When the barge was in tow, and with the more rapid rate then assumed, nearly seven miles per hour, there was no perceptible swell behind the barge, the swell from the wheels not appearing after meeting the bow of the barge. There was no obvious change in the character of the swell at low and high velocities, but the experiments did not permit numerical accuracy upon this point. At the time when the heights of the wave from the barge and from the steamboat are noted in the remarks, the barge was so far before the boat that the latter was free from any effect produced by the swell of the former. It was in the deep cut, and the bow of the barge was elevated, and the stern depressed, mounting an inclined plane, while, besides the wave which preceded the bow, a destructive surge followed sweeping above the stoning of the banks of the tow-path. The wave from the steamboat was included within limits comprising only a portion of the cover of the banks, and did not break with the violence necessary to carry away the soil and pebbles from behind the stones. The boat suffered no sensible retardation in passing into the deep cut, for in the latter part of the second experiment, with thirty-six and thirty-seven revolutions, the speed was about seven and a half miles per hour, while in the wider portions, with thirty-seven and a half, the speed was about seven miles and three-quarters. The same conclusion is to be drawn by comparing these results with those obtained in the Schuylkill; in fact, the average speed with a given number of revolutions upon the canal, rather exceeds that with the same number upon the river. The want in power of the engine prevented the experiments from being conclusive in relation to towing, with high rates of motion, though they seem to indicate greater advantages from towing, at rapid rates,than in moving with the boat alone. That the speeds attained by even this imperfect model, compare with those which the labor of eight horses is capable of producing, appears by the annexed memorandum receiv ed from the captain of one of the passenger barges which passes daily through the canal on the line from Philadelphia to Baltimore. The average speed is about nine minutes to the mile, and two hours are required to pass the canal.” While then it would seem to be an easy matter to exceed the average speed which is attainable in towing by horses, the swell produced by one and by the other mode of conveyance are not comparable with each other. |