Canal Technology

Canal Locks

Before the invention of locks to adjust water levels to land levels, canals were built on level surfaces.   For example, in the Netherlands, the canals were branches of the original sea.   Some adjustments of canal levels to varying contours of the land were made by using inclined planes to transfer boats to different levels.   This method is limited by the size and weight of the canal boats, however.   The development of the canal lock was gradual and its inventor is unknown.   The land of its first adoption also is doubtful.   Italy claims the honor for two brothers, engineers of Viterbo, in 1481, also for the famous engineer and painter, Leonardo de Vinci.   Some writers attribute the discovery to Holland a century earlier.   It is definitely known that during the latter part of the fifteenth century, locks were in use in both countries. ^Whitford

Inclined Planes

In 1829, the Morris Canal Company constructed four planes: One at Bloomfield, one at Pompton, one at Montville, and one at Booneton.   The two first have a lock at the head of the plane to admit the boat to be floated directly on to the car by filling the lock to the same height as the water in the upper level.   The other two are called summit planes because a boat must pass over an elevation or summit raised above the top waterline of the canal preparatory to its descent down the plane.   Although there were but two kinds of planes, neither two of those finished were similar in all their details.   Loaded boats were passed frequently on each of these planes with safety and speed, but as in all experiments of new machines, it required repeated trials and close observation to discover their defects, and to show wherein they might be improved. ^Whitford

The Bloomfield plane with a lock at the head connecting it with the upper level of the canal is 740 feet in length, the descent of 70 feet in the lock is one foot in 24 feet, in 600 feet of the plane, one foot in 12, and in 70 feet at the foot of the plane it is nearly level.   The entire descent is 54 feet.   The place selected for this plane has a sloping surface corresponding nearly with the descent of the plane.   After graveling the plane, trenches were dug below the frost line and four walls of masonry of about 2½ feet wide by 3 feet above the surface of the ground were laid the entire length of the plane.   Oak timbers were placed on these walls, and cast iron rails of about 4 inches wide and 2 inches thick having a convex upper surface are secured by spikes with countersunk heads to the top of the timbers. ^Whitford

There is a lock at the end of the track upon each side at the head of the plane that enables the boat to float directly on to the cradle of the car.   These locks have double gates of the usual construction at the head, and a single gate similar to the English safety gate at the foot, which when open lies at the bottom of the lock.   These locks and also the cradle are made of a size just sufficient to receive the boats that usually navigate the canal.   There is a car upon each track supported by four cast iron wheels seven feet in diameter with a concave rim made to conform to the upper surface of the rails.   From this car, a cradle is suspended by iron rods, the top of which is level with the upper mitre sill, on which the boat in its transit rests.   An iron cable chain passes round a drum wheel above the lock and one end is attached to each car.   This chain is of sufficient length to extend from the car at the upper level in one of the locks to the other car at the foot of the plane. ^Whitford

The drum wheel around which the chain revolves is on a perpendicular shaft connected with a horizontal waterwheel shaft by spur and bevel wheels upon each side of the drum wheel.   The whole machine moves by water drawn from the upper level on to the waterwheel; this water, as well as that from the lock, is discharged into the lower level by a ditch for that purpose at the side of the plane.   The wheels of the car and the railway or track of the plane are elevated to allow the axle of the car wheels to pass over the sides of the lock, and the wheels pass upon the outside and do not interfere with the lower gate of the lock. ^Whitford

The boat is introduced from the upper level after filling the lock through the paddle gate when the car is in the lock.   This water raises the lower gate to its place and the lock fills to a level with the water in the canal.   The boat is then floated in, the upper gate shut, and by discharging the water from the lock, the lower gate falls by its own weight to its place, and the boat settles down upon the cradle, and is ready to move down the plane.   The plane is so constructed that a boat may pass up or down the plane singly or a boat may pass each way at the same time.   There is a friction-break on the rim of the waterwheel to regulate the motion of the car, and also the common governor is applied for the same purpose.   The governor is turned by a bevel wheel on the arms of the car wheel, and any accelerated motion of the car wheel would cause the balls or arms of the governor to fly out and disengage wedges that would fall before each wheel and cause the stoppage of the car in any part of the plane." ^Whitford

After this plane was constructed, the Morris Canal Company engaged Major D. B. Douglass to take charge and superintend the work on all the planes.   He adopted the form known as the summit plane, but made such alterations and improvements in the machinery and cars as to obviate the imperfections of the planes first built, including the one at Bloomfield.   Those on the improved pattern were under construction at Newark while Mr. Hutchinson was on his tour of inspection and later, after they were brought into operation, he received information from Mr. Douglass concerning the test, which was highly satisfactory.   The Newark plane has a rise of 70 feet, in a length of 770, but the extreme length of the ways is 1040 feet.   The ascent is uniform from the surface of the water in the lower level to the height of that in the upper, at which point the summit curve begins and the ways, after rising one foot higher, descend into the water of the upper level. ^Whitford

There are two pairs of tracks, on each of which is a car of very strong construction, supported by 8 wheels, so arranged that the car may pass over the summit and from one declivity to another with an equal bearing on the whole eight wheels.   The cars are connected with the machinery by cable chains, capable of bearing a strain of 15 tons without alteration.   Upwards of 20 tons are required to break them.   The strain put upon them by the operation of the plane is calculated never to exceed 6 tons.   The moving power is a waterwheel of 24 feet diameter, placed a short distance down the declivity of the plane.   In the ordinary condition of the plane, one car stands in the upper level, the other in the lower, and a boat may pass in either direction, or two boats in opposite directions at the same time.   The first part of the operation is to draw the car out of the upper level by a separate action of the water wheel.   As soon as it has passed the summit and begins to descend, the main machinery goes into action, and then the ascending car begins to move.   The motions of the two reciprocate until the descending car reaches the bottom of the plane, at which time the ascending one goes over the summit, and descends into the upper level by its own gravity, independently of the machinery. ^Whitford

From the proposed use of inclined planes on the Black River Canal, quoting engineer Hutchinson: ^Whitford

"The time of passing is of course subject within certain limits to the discretion of the engineer, depending upon the power of the water wheel, and the train of the machinery. My water wheels, in the cases mentioned, were calculated with power sufficient to elevate the loaded cars at the rate of six feet vertically per minute. The average of their performance was nearly seven, but I do not think it desirable when moving up under full loads, that they should exceed that originally calculated; in the descent they will naturally move somewhat faster, at an average say of 12 minutes for a lift of 75 feet. To this we may add 2 minutes for getting the boat into the car and making it fast; making 14 minutes for the whole operation. The detention of the boat, however, does not equal this time, as it has advanced about 1100 feet in the operation, which is equal to full four minutes of its motion, at the ordinary rate of travelling. The difference, therefore, or ten minutes, is the nett detention for the lift mentioned, or 7 ½ feet per minute. Comparing this detention by lockage, it will be seen that the plane of 75 feet can be passed in about the same time as a ten foot lock, and that a planage of 1500 feet is no more formidable in this respect than a lockage of 200.

"From the foregoing calculations, we perceive that the plane of 75 feet is occupied 14 minutes by a single operation, including 2 for getting into the car and making fast. At this rate the plane will easily make 4 operations per hour, (in fact it did five with ease in our experiments,) and afford planage to four boats in each direction. Whether the boats present themselves regularly or not, is not material, as the question of capacity is only interesting on the supposition of a crowded navigation; and it is presumed that few cases can occur in which it would be necessary to pass more than four boats per hour in one direction, or more than eight in both. Taking an average case, we should pass 6 boats per hour in both directions, which is about equal to the performance of a lock. Independently of this comparison, however, we can be quite sure that an inclined plane of 75 feet lift, supposing an average lading of 20 tons would pass 80 tons per hour, or 1,600 tons in twenty hours per diem, in each direction, which is at least one half greater than the whole commerce of the Erie canal, at the busiest season of the year. Cargoes of 25 tons would make 100 tons per hour in each direction, or 2,000 in 20 hours per day.

"The expense of inclined planes. This, estimated by the foot-lift, will vary considerably for planes of different elevations. The water-wheel machinery and cars being the same for all elevations. Taking that of 75 feet, however, as an average, and the tonnage the same as that upon the Morris canal [25 tons], the cost will not materially vary from $210 per foot-lift; a plane of 50 feet might rise as high as 250 dollars; lower lift, if no variation was made in the machinery, would rise still higher: but I am inclined to believe that an arrangement of single cars and more simple machinery could be adopted with advantage, for planes of less than 45 feet lift, which would keep the expense within the limits of 250 dollars, even for planes of no more than 25 feet lift."