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29th March 1932, Page 50
29th March 1932
Page 50
Page 51
Page 52
Page 50, 29th March 1932 — THE MECHA ICAL HORSE
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Interesting Tests Indicate Usefulness of the Karrier Cob for Hauling Barges. Superior Acceleration Valuable in Negotiating Locks

Slight Modifications to Towing Paths,also to the Design of the Tractor, Would Open Up an Extended Field of Usefulness THE object of Karrier Motors, Ltd., Huddersfield, in producing the Karrier Cob was to offer to horse-transport operators a machine which would replace the horse without necessitating the abandonment of carts, drays and other gear which might still have a considerable useful life. The Cob has been proved capable of doing ninch more work hi a given time than a horse, and thus permits of increased efficiency without involving heavy capital loss.

In the issue of this journal dated December 1st,

1931, we reported fully upon tests made in conjunction with Birmingham Corporation in the use of a Karrier Cob and two trailers (purchased by the municipality) in competition with horse-drawn drays which, for years, had been used in delivering coke from the gasworks. Operating costs were given and showed an advantage in the case of the Cob.

Karrier Motors, Ltd., has successfully explored many fields of usefulness for this machine, such as in local cartage, chainhorse work, transport within factories, etc., and has now turned its attention to the haulageof canal barges. In conjunction with the Severn and Canal Carrying Co., Ltd., and the authorities controlling the Birmingham-Worcester Canal, some interesting tests have been carried out, and we have been afforded an exclusive opportunity for observing these and investigating the proposition.

The Karrier Cob employed for the tests was an ordinary solid-tyred machine, having no special equipment except a towing pillar, yet it was able, in many respects, to better horse performance. It had the standard top-gear ratio of 10.2 to 1, which was


rather too high for the job, so that second gear (24 to 1). was used a good deal. The size of the solid tyres was 18 ins. by 5 ins. (single rear), and, an important point, the overall width of the tractor was 4 ft. 4 ins. An ordinary spring towing pillar was fitted and a box containing 8 cwt. of ballast was bolted to the frame above the rear axle.

As to the type of barge used, this was the standard maximum-size vessel employed by the Severn and Canal Carrying Co., Ltd., on this canal, being made

exactly to fit the locks and having the maximum permissible draught of 3 ft. 9 his. The barge is 72 ft. long and 7 ft. wide and carries a pay-load of 33 tons ; it is made throughout of English oak and the dead weight is 14 tons.

The section of the canal chosen for the tests was that between Tardebigge, near Bromsgrove, and Worcester. It is about three miles long and there are no fewer than 33 locks, these accommodating the big fall in the land level between Birmingham and Worcester. The canal is wide enough in most places for two barges to pass, but each lock just accommodates one barge with only a few inches to spare in length and width. The towing path is of earth and cinders, and in most places is about 8 ft. wide. Under bridges and in other places its width narrows to about 4 ft. 9 ins..

We observed a journey made with one barge downward from Tardebigge to the 15th lock, returning with another barge to our starting point. On straight runs the Cob could reach a greater speed than the wash against the canal bank usually permits and, of course, speeds out of all proportion to those possible with horse haulage. The most striking advantage, however, was in connection with acceleration out of the locks.

Whether horse or tractor be employed, acceleration is facilitated by the use of a pulley block, this doubling the leverage ratio during the first few yards after starting from rest. The tractor was able to pull the laden barge clear of the lock in a time averaging about 32 seconds, the horse taking about 55 seconds. Adding to this the factor of extra speed, the journey could be effected in considerably less time.

An interesting point is that there was no objection to the barge, on the downward journey, entering the locks at greater speed, because the practice is to give the stern hawser two turns around the gate bollard, so pulling the lock gate shut and bringing the barge to a standstill.

On the upward journey more effort is required when entering locks and, as the towpath makes an abrupt rise just by the Jock entrance, a severe test was afforded of the tractor's capabilities. In cases where the surface on the incline was soft, the method adopted was to get good way on the barge, travel more or less light up the incline, and give a final pull from the higher level as the bow of the vessel entered the lock gates.

With but minor alterations the Karrier Cob could be made still more suitable for canal work. It is doubtful whether the differential gear should or should not be dispensed with, but whilst the tractor must negotiate awkward turns when passing under bridges along a path of only 5 ft. in width, it would appear advisable either to retain the standard differential gear, or to fit a locking device. To reduce the height of the towing pillar would afford an advantage, and possibly it could be given optional positions on the near side and on the off side of the frame.

Another simple improvement would be to make the ballast weight movable by screw gear to the side away from the barge. Pneumatic tyres would provide a better grip, and the width of the machine could be. reduced. For hauling one barge a still smaller engine might be employed with a lower range of gear ratios, including an extremely law ratio which would give almost a "standstill pull." Karrier Motors, Ltd., is closely watching all these points.

B34 The reason why a flight of locks was chosen for this test was that it could be shown how the Karrier Cob would save the gruelling work which horses are obliged to perform in restarting heavy barges from rest when leaving locks. It should be understood that, if it were not for the falling level and the resulting series of locks, motor barges could be used, as elsewhere.

These vessels have Bolinder single-cylindered 20 b.h.p. oil engines and each hauls two loaded trailers. This raises the question as to whether the Cob would be useful on straight pulls over long distances with two or three barges. It appears that it would.

One must realize that the problem of the carrying company is not simply one of ascertaining whether it is cheaper to employ motor barges, tugs or a light tractor for such work. It may be necessary for a cargo to leave on a journey before a train of three barges can be made up.

To hold back that cargo may inconvenience the consignee, or it may upset the carrying company's plans for return traffic. Thus, to have available light tractors which, with their different gear ratios, would be ready to move off at a minute's notice with one, two or even three barges, and to haul them either on straight runs or through a flight of locks at a greater speed than the horse is capable of, may result in an overall increase of economy and efficiency, even if the cost of operat ing the tractor should be a little more than that of keeping horses.

It might even pay to modify towing paths to facilitate the use of these tractors. Assuming the latter have a width of just under 4 ft., bays of at least 8 ft. width would be necessary every 200, yds. or so to permit tractors to pass. The towing-path surface might be consolida,ted on the abrupt slopes at the locks; the surface might also be improved in places where it is liable to become exceedingly muddy in wet weather. Apart from this, given pneumatic tyres and suitable gear ratios, the tractor should not cause much damage to the path, neither should it experience difficulty in working.

The whole question of obtaining the most efficient form of power for canal transport is at present receiving more attention than is generally thought. The stumbling block to progress is the variety of tolls and working conditions imposed by canal authorities.


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