Part 2

The question of the weight of the truck used for logging purposes is not as important now as it will be in the future. Laws are being passed in nearly every state limiting the maximum weight to be carried on each wheel by trucks using state or county roads so that the total weight of the truck without load will be important. When operating over state or county roads the load is limited to from 2400 to 3000 feet, B. M., of Douglas fir, depending upon the locality. In such cases, it is an advantage to have a lighter truck, say one of 3½ tons capacity. By adding additional leaves to the rear springs of a truck of this capacity it may be made to carry a larger load than it would be possible to put on a 5-ton truck and still comply with the law. The pulling power of the 3½-ton truck and the 5-ton truck is practically the same so that the difference in dead weight between the two may be carried in a profitable manner by adding four or five hundred feet B. M. of logs. Another advantage of the lighter weight truck is _speed_. The 3½-ton truck is geared to make from 14 to 16 miles an hour, while the 5-ton truck is usually limited to from 10 to 12 miles an hour.

Whenever the legal weight limit does not enter into the problem, as in operating over a pole or plank road for the entire distance, it is, of course, advantageous to carry the largest loads possible. In such cases a 5-ton truck with an 8½-ton trailer is the most profitable investment. This allows a much larger load to be carried in proportion to the overhead charges. The disadvantage of the 5-ton truck is that it is very heavy and unless the roads are good, it will easily sink into the ground and cause trouble. A common fault of the 5-ton truck today is the overweight of the front end, which is too heavy for the width of tire on the front wheels. This can be very easily overcome by the use of wider tires.

LIFE AND DEPRECIATION

The life of a truck is directly proportional to the care that it receives, hence, a good driver is a most important consideration. If the right man can be secured his wages should be a secondary consideration.

The charge to be made for the depreciation of a truck is an uncertain question. Some loggers figure on the basis of four and a half years, others on as much as seven years. The depreciation charge on a truck used in the logging industry should depend largely upon the type of road over which it is operated. Loggers in general over-rate the life of their equipment because they do not fully realize the severity of the work. Over a fore and aft plank road or a cement road, where the jar and vibration are reduced to a minimum, the wear and tear on the equipment is very much less than where the truck is operated over a cross-plank road or an unpaved public road. The matter of depreciation, then, will depend largely upon the type of road over which the truck is to operate. In general a four-year depreciation charge less 25% sale value at the end of that time should be used as a basis for figuring costs unless the hauling conditions are very favorable. Only under very rare circumstances should more than four years be allowed. It should be remembered that the depreciation on a truck is very heavy during the first year, and the sale value at the end of a year is only half the original price. Many truck operators now hauling over good roads who are depreciating on the basis of five years say that a four-year depreciation would be more nearly correct. Another factor in favor of a four-year depreciation charge is that methods of logging are changing constantly and that trucks in that time may be improved upon to such an extent that the use of the old equipment would be unprofitable and inefficient.

INSURANCE

The insurance rates on trucks depend upon the use to which they are put. The insurance usually carried by loggers covers fire and theft, although some companies also carry liability and either collision or property damage insurance. The equipment can be insured for only ninety per cent of its value.

Fire and theft insurance is based upon the list price of the truck and body when new and the usual premium for the logging truck is one dollar for every hundred dollars of insured value. Theft rates on the trailer are based on a flat charge of twenty-five cents per hundred dollars of insurance taken, regardless of age, list price, etcetera.

Collision insurance is based upon the list price of the equipment and covers full value at the time of loss of the damage to the truck by colliding with anything movable or immovable.

The liability rate for logging trucks is $33.75 and is based upon occupation alone. This covers the public as well as the employee and is limited to $5,000 for one person and $10,000 for two persons or more.

The property damage rate for logging trucks is $13.50, and covers the damage done to the property of others. It is arrived at in the same way as liability insurance. The usual limit for property damage is $1,000.

TRUCK EQUIPMENT

_Bunks._ All trucks for use in log hauling are equipped with a patent bunk over the rear axle on which the logs rest (see illustration on page 13). This is essentially a steel I-beam (A) which grips the logs so that they will not slip. At each end of the bunk are V-shaped iron chock-blocks (B) held by chains which run under the I-beam and are fastened by an iron gooseneck hook (C) so that the load is kept from spreading. These blocks may be adjusted to any width of load. The whole bunk is mounted on a swivel so that it will turn with the logs when rounding a sharp turn in the road. When dumping the logs at the landing, each block is loosened from the opposite side so that the danger of the logs rolling off on the men is greatly lessened.

_Tires._ Solid rubber tires are generally conceded to be the best suited for the heavy duty required in logging. The use of steel tires is rapidly declining. The jar on the equipment is in itself enough to condemn their use. Rubber tires double the mileage of a day's work, more than double the life of the equipment, allow the weight of the equipment to be cut in half, and work well on dirt, cement, or any other type of road. The saving on the life of a pole or plank road by the use of rubber tires is also an item of considerable importance. There are three general types of solid rubber tires in use on the logging truck: the so-called giant tires, the duals, and the non-skid or caterpillar tires. It is a question as to which of the three is the best. Traction for the drive wheels and also for the trailer wheels, if the latter are equipped with brakes, is the problem to be solved.

The duals are satisfactory with light loads and easy grades, on cement, brick, or other perfect surface road, but when the haul is heavy and the braking difficult on account of heavy grades, the larger single-tread giant tires are more efficient. During dry weather it is safe to work with the single-tread tires on grades as high as nine or ten per cent, but in wet weather a seven per cent grade should be the maximum unless some extra means are taken to secure traction, and even then the wheels will skid if particles of soil get on the surface of a plank road, unless chains are used or the wheel is wrapped with a light cable.[4] For very heavy-duty trucking, where resiliency and long service are prime considerations, the giant type is rapidly superseding the old dual type as the former contains more rubber and gives more mileage with the least truck vibration.

[4] West Coast Lumberman. October, 1919. Page 25.

The non-skid or caterpillar tire may well be used on heavy grades or where the traction is very poor, the general opinion being that it gives a firmer grip on the road and makes it safer to handle the truck in wet weather.

There is no standard width of tread for truck wheels. The widths usually used on the drive wheels of the logging truck and the wheels of the trailer are twelve and fourteen inches, respectively. The use of tires of smaller width on either trailer or truck cannot be recommended. The wider the tires on the trailer, the better it is both for the life of the equipment and for ease in handling the load. When the surface of the giant tires becomes worn down so that the grooves become very shallow, it is desirable to have the tires re-grooved. They will last a great deal longer if this is done and will also give better traction on the road. The groove makes the tire lobes act separately on the uneven places in the road so that only one lobe is subjected to the strain of the irregularities instead of the whole tire. This is also true with reference to the strains that are set up internally due to the twisting of the rubber.

LAWS GOVERNING THE OPERATION OF MOTOR VEHICLES

The Laws governing the operation of motor vehicles upon the public highways of the State of Washington are contained and summarized in Senate Bill No. 220, Session of 1921 of the Legislature of the State of Washington. They include the following provisions governing the operation of motor trucks and trailers:

(a) Chapter 153 of the laws of 1913 and Chapter 142 of the laws of 1915 are repealed.

(b) Motor truck vehicles weighing less than 1,500 pounds must pay an annual license fee of ten dollars ($10.00); Trucks weighing more than 1,500 pounds and not to exceed 6,500 pounds, ten dollars ($10.00) plus forty cents per hundredweight for all in excess of 1,500 pounds and in addition thereto fifty cents per hundredweight at the rated carrying capacity. Motor trucks weighing more than 6,500 pounds must pay a license fee of ten dollars ($10.00) plus fifty cents per hundredweight for all in excess of 1,500 pounds and in addition thereto fifty cents per hundredweight at the rated carrying capacity. Trailers =used as trucks= shall be classified and rated as, and shall pay the same fees as hereinbefore provided for motor trucks of like weight and capacity.

(c) No vehicle of four wheels or less whose gross weight with load is over 24,000 pounds is permitted to operate over or along a public highway. Any vehicle having a greater weight than 22,400 pounds on one axle, or any vehicle having a combined weight of 800 pounds per inch-width of tire concentrated upon the surface of the highway (said width of tire in the case of solid rubber tires to be measured between the flanges of the rim) is also barred by the provisions of this law, with the following exception:

PROVIDED, that in special cases vehicles whose weight including loads whose weight exceeds those herein prescribed, may operate under special written permits, which must be first obtained and under such terms and conditions as to time, route, equipment, speed and otherwise as shall be determined by the director of licenses if it is desired to use a state highway; the county commissioners, if it is desired to use a county road; the city or town council, if it is desired to use a city or town street; from each of which officer or officers such permit shall be obtained in the respective cases. Provided, that no motor truck or trailer shall be driven over or on a public highway with a load exceeding the licensed capacity.

_Chain Drive._ Trucks equipped with a chain drive should be supplied with an extra set of chains so that they may be changed and cleaned every week. To clean the chains, they should be soaked in kerosene which removes the dirt, grease and gum that has accumulated. By doing this the life of the chains will be quadrupled. The small amount of time that it takes will pay.

_Top._ The truck should come equipped with a top over the driver's seat that is easily detachable. In bad weather the driver should be protected from the elements, but the top should be removed in good weather as it is in constant danger of being broken during loading. Many operators leave the top off entirely and the driver must dress for the weather. A good demountable top will add to the comfort of the men and often helps to keep a good man at his job.

TRAILERS

The development of the trailer has made motor truck logging practical. Every truck has greater tractive power than it can utilize in the propulsion of the ordinary load. Its limitations are due to a short-bulk carrying capacity and not to any lack of pulling power. The ordinary truck has a draw-bar pull of 2600 pounds. The draw-bar pull per ton of load varies from the minimum of 50 pounds on a level pavement to 250 pounds on a level dirt road, depending upon the character of surface.[5] Twenty pounds of additional pull are required for each degree of gradient. For example, a fore and aft plank road offers a resistance of about 60 pounds pull to a ton of load. If this were located on a seven per cent grade, it would require a 60 pound pull to overcome the load resistance plus seven times twenty or 140 pounds additional pull for the grade, a total of 200 pounds to pull one ton. Dividing 2600, the draw-bar pull of the truck, by 200, the resistance offered by road and grade, gives 13 tons as the load that can be pulled by the truck over this surface and grade. As this must include the weight of the trailer, which when equipped for logging is about three tons, it leaves a total of 10 tons that the truck can pull. This is equivalent to about 3000 feet B. M. of Douglas fir logs, the average load that is hauled. While such an adverse grade as cited in this illustration is avoided if possible with a loaded truck, the illustration will serve to show the pulling capacity of the truck. The hauling of loads of this size would be impossible without the use of the trailer. The normal load, then, may be increased two, three, or even four times, by the use of the trailer, over the maximum load that can be carried by the truck alone.

[5] Operating Cost of Motor Truck Computed. Timberman. Feb., 1918. Page 60.

Objection to the trailer that it tends to shorten the life of the truck is hardly worth consideration. According to a careful analysis it has been estimated that the use of the trailer does not shorten the life of the truck by more than one year, which is of little consequence when the saving due to the size of the load that can be carried is taken into consideration.

_Description of the Trailer_: The frame of the trailer is constructed of heavy steel channel bars which support the twin bunks used for logging, and for the substructure to carry the body when used for other service. The steel frame is supported by semi-elliptic springs held by shackles similar to those of the truck. The springs rest securely upon the axle, are clamped to it by U-bolts, and are relieved from side stresses by radius rods which connect the axle to the frame.

The trailer is coupled to the truck by a reach which is passed through guides secured to the hounds of the trailer. The latter may slide upon the reach and is held in the desired position with reference to the truck by means of clamps. The hounds are located fore and aft of the axle and are connected to it by steel plates. The square reach is more favored generally by loggers than the round type for the reason that it can be more easily adjusted, particularly the round reach that is cut in the woods, which is irregular and has to be clamped very tightly in order to make it stay in place. Holes bored through the square reach makes the adjustment easy. Combination steel and wood reaches, the sides being of channel iron and the center of wood, are favored by some operators.

The twin bunks of the trailer carry the load in balance upon the axle independent of the reach, thereby relieving the reach of all vertical stress. (See illustration below). The rear bunk is just an ordinary wooden affair designed only to help support the weight of the logs. The front bunk is of the same construction as the one on the truck (described above) and serves to hold the load in place.

The trailer is guided through the reach directly to the axles, thus relieving the springs and frame from side stresses. The springs and their suspension from the frame permit a limited movement of the frame and the load independent of the wheels and axles and vice versa. This enables the wheels to pass over an obstruction or drop into a hole without subjecting the trailer to shocks that would otherwise ensue.

Other types of trailers are used to a limited extent. The trailer described above was evolved by local engineers and is in almost universal use in motor truck logging operations.

_Brakes._ All trailers should be equipped with brakes when negotiating heavy grades. A device connecting the trailer brakes to the truck permits a ready control from the driver's seat on the truck. The brake outfit is easily attached to the truck and consists of a ratchet and lever which winds a one-quarter inch cable on a small drum. The cable winds around a second drum which is attached to the frame of the truck about six feet back of the driver's seat. A third drum in the center of the chassis attached to the shaft of the second drum winds a cable which goes to an equalizing bar just in front of the trailer brake. As the ratchet and drum are tightened, the motion is transmitted through the second and third drums to the equalizing bar. Two arms extend from this bar to roads which when pulled forward, move a bar attached to the road in such a way that the brake band in the inside of the brake shoe is extended against the shoe, applying the brakes evenly to each wheel no matter how uneven the road-bed or how sharp the curve. A spring attached to the reach clamp pulls back the equalizing bar when the brakes are released. A heavy spring on the drum in the center of the shaft on the truck allows for curves so that an even pressure is always maintained.

The use of a trailer equipped with brakes will do away with the numerous devices for snubbing a load of logs down a grade not steeper than twelve per cent. Grades up to this degree of steepness are safe to operate over in dry weather without added braking power if the trailer is properly equipped.

A simple and it is claimed an effective air brake for motor trucks and trailers is now being marketed by an air-brake concern of San Francisco but it has not yet been tried out in the logging industry. "Braking action is secured by means of a diaphragm and pressure plate. The diaphragm is directly connected to the brake-band lever. No air compressor is used in this system. A small air receiver or storage tank takes the spent gases from one of the cylinders by utilizing the outlet afforded by a priming cock. The brakes are applied by a control system mounted on the steering column. By means of a quickly adjusted hose connection, air can be applied to the wheels of the trailer using the control which governs the braking of the truck. The air pressure in the storage tank is automatically maintained by means of an accumulator valve which closes when the tank pressure reaches 150 to 175 pounds. If the tank should be empty at the top of a long grade, sufficient pressure is generated by the compression of the engine to operate the brakes. Opening the throttle to full emergency position will apply maximum braking effect without sliding the wheels."[6]

[6] Air Brakes for Trucks. Timberman. March, 1920. Page 48g.

This system has not been tried out under the conditions as found in the woods but if it can be made to work satisfactorily it will be a big improvement over the old system as the driver will then have instantaneous control over the load at all times.

LIFE AND DEPRECIATION

The life of the trailer is about the same as that of the truck, and in depreciation, a period of four years is usually allowed. The maintenance and upkeep of the trailer is very low. It rarely gives out and with the ordinary usage requires only a few minor repairs every two or three years.

COST DATA

The items of expense are here segregated in such a manner that they may be used as a basis for figuring the cost of hauling logs under average conditions. These costs are for the truck and trailer as a unit. If a road has to be built, the overhead charge of the road per thousand feet of timber hauled over it together with the cost of upkeep must be added to the figures given below in order to know the total cost of transportation per thousand feet.

3000 FOOT CAPACITY, OUTFIT COMPLETE

The following figures are for a 3½-ton logging truck with a 5-ton trailer. The figures are based upon a 275 working day year.

Cost of equipment (as a basis) $6700.00 Less resale value at expiration of 4 years at 25% of the original cost $1675.00 Less cost of tires, 2--36" × 6" $140.50 4--40" × 12" 776.00 916.50 -------- -------- Total $916.50 $2591.50 2591.50 -------- Basis for computing $4108.50

RUNNING EXPENSES PER MILE

Per Mile Tires, based on a cost of $916.50 and a life of 8000 miles $ .1145 Gasoline, four miles to a gallon @ $ .28 per gal. .07 Oil and grease .02 General repairs .03 -------- Total running expenses per mile $ .2345

FIXED CHARGES PER 275 WORKING DAY YEAR

Depreciation, based on 25% per year on $4108.50 $1027.12 Interest on money invested at 6% (figured on truck less cost of tires) 347.01 Driver at $7.00 a day 1925.00 License 27.00 Insurance, Fire, Theft and Liability based on $1 a hundred on 90% of the value of the new truck for fire and theft, and a flat rate of $33.75 for liability 90.75 ------- Total fixed charges for 275 day year $3416.88 Total fixed charges per day 12.418

TOTAL EXPENSES

30 40 50 60 70 miles miles miles miles miles Uniform variable charges $7.035 $9.38 $11.725 $14.07 $16.415 Fixed charges 12.418 12.418 12.418 12.418 12.418 Total charges (per day) 19.453 21.798 24.143 26.488 28.833 Total cost per mile, loaded one way only .648 .545 .482 .441 .412 Total cost per 1000 ft. per mile with 3000 ft. to the load .216 .181 .160 .147 .137

4000 FOOT CAPACITY, OUTFIT COMPLETE

The following figures are for the 5-ton logging truck equipped with an 8½-ton trailer, based on a 275 working day year:

Cost of equipment (as a basis) $7600.00 Less resale value at expiration of four years at 25% of original cost $1900.00 Less cost of tires: