Supplying War 2nd edition - vehicle efficiency

Discussions on the economic history of the nations taking part in WW2, from the recovery after the depression until the economy at war.
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Der Alte Fritz
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Supplying War 2nd edition - vehicle efficiency

Post by Der Alte Fritz » 06 Feb 2017 09:53

In the second edition of "Supplying War" by van Creveld, in the chapter "logistics in perspective" (p234 in my edition) he discusses the how armies attempt to move forward while supplying themselves and how far they are able to move forward. He makes the point that the theoretical distance for vehicles is never achieved for instance:

a horse drawn wagon 4 horses each consuming 20lb of fodder a day gives a maximum distance before using up its entire payload as 20 X 2,240 /80 = 55 miles of which 120 miles has ever been used in practice ie. 22%

a 5 ton WWII lorry loaded with nothing but fuel could travel at least 5,000 miles before using all its fuel. However at most only 10% of this has been used as armies seemed unable to support themselves more than 500 miles from their bases using lorries so there are greater losses with using lorries than with horses.

What is it that stops an army supplying itself over a distance of 1,000 miles as Rommel tried to do in the Western Desert? An individual lorry can drive that far although it may take some time so you would think that adding further lorries would allow them to deliver a fixed load at any distance. Of course there is some element of the law of diminishing returns as at great distances as fuel starts to take up an increasing proportion of the load but at 1,000 miles you should still have 4/5 of your payload available so not too much of a drop.

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Re: Supplying War 2nd edition - vehicle efficiency

Post by Der Alte Fritz » 06 Feb 2017 10:36

My starting point in this investigation was the 1941 edition of the Field Service Pocket Book to see how armies really moved by lorry. This stated that:

average speed = 30 mph (this is the speed needed to be used by the driver on most stretches of road)
miles in the hour = 10-15 mih (this is the actual distance travelled in an hour when allowance is made for other traffic on the road, rest stops, minor breakdowns and traffic crossing the road.)
vehicles per mile = 20 (which relates to a 90 yard spacing between vehicles to allow for air attack)
vehicles passing a point in one hour = 200 (vehicles per mile x their rate of progress 10 mih)
travel per day = 150 miles
length of working day = 12 hours
number of lorries used = 2,400

So this gives us "at the end of the road in one day" using a 1 ton standard sized vehicles an effort of in ton miles:

tonnage (number of vehicles passing a point x number of hours of operation x tonnage) x distance (150 miles)
or
(200 x 12 x 1) x 150 = 360,000 ton mile

----------------------------------------------------------------------------
so if we want to deliver a fixed amount at a set distance it works out like this:

360,000 / distance = tonnage
or
360,000 / tonnage = distance

50 miles = 7,200 tons
100 miles = 3,600
150 miles = 2,400
300 miles = 1,200
600 miles = 600

2,400 tonnes = 150 miles
4,800 tonnes = 75 miles
9,600 tonnes = 37.5 miles

Th first point to note is that this scheme ends up with all the lorries at one end of the journey at the end of the day. So for a continuous supply operation where they need to do the same the following day, you need to get the lorries back to the starting point by the end of the day and so you have to divide these figures by half. 150 miles translates into 75 to destination and then 75 miles back in one day.

Secondly it is obvious that for every days travel you halve the amount carried, so a better way to express the problem would be in "day marches" (which would be both the journey to the destination and the return journey), so using our 150 miles a day example and a days march of 75 miles:

1 days march = 2,400 tons
2 days march = 1,200 tons 1/2
4 days march = 600 tons 1/4
6 days march = 400 tons 1/6
10 days march = 240 tons 1/10

From this it is easy to see how distance is eroding the carrying capacity of the fleet at 6 days at 75 miles = 450 miles.

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Re: Supplying War 2nd edition - vehicle efficiency

Post by Der Alte Fritz » 06 Feb 2017 11:01

The German view can be found in "Versorgung der Feldheeres" H.Dv.g 90 (the secret annex to the main document)

They use a formula to deal with the loading and unloading factors:

L = (14 - 2X) * 225 * Y * Z

L = Daily amount carried in ton km
ton km = distance (km travelled) and cargo transported for a certain time (1 hour or 1 day)
X = number of successful journeys with load
Y = number of Small Motor Columns (30 ton) (double this for Large Motor Columns 60 ton)
Z = State of roads:
State Highways = 2.5 Main Roads = 1.6 Variable road conditions, (good roads, field roads, steep gradients) = 1 Forest and Field Roads, Steep climbs = 0.7
(These figures depend on the time of day, night journeys multiply by 0.7 journey completely in daylight by 1.3)

14 = number of working hours (8 hours allocated to rest period and vehicle maintenance and 2 hours for drivers hot meals)
225 is a constant (average speed 15 km/h of a Small Motor Column and useful journeys 0.5 to account for the return journey. 15 x 30 x 0.5 = 225)

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Re: Supplying War 2nd edition - vehicle efficiency

Post by Der Alte Fritz » 06 Feb 2017 11:10

Example 1.
Daily journey using 2 Small Motor Columns:

a) 1 journey L = (14-2 hours) * 225 * 2 (columns) * 1 (average roads) = 5400 ton km. So to deliver 60 tonne in 1 journey = 90 km

b) 2 journey L = (14-2*2 hours) * 225 * 2 (columns) * 1 (average roads) = 4500 ton km. So to deliver 120 tonnes in 2 journeys = 37.5 km

c) 3 journey L = (14 - 2*3 hours) * 225 * 2 (columns) * 1 (average roads) = 3600 ton km. So to deliver 180 tonnes in 3 journeys = 20 km

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Re: Supplying War 2nd edition - vehicle efficiency

Post by Der Alte Fritz » 06 Feb 2017 11:15

Example 2.
Every day 6 Small Motor Columns bring up 360 tonnes of ammunition. How far can they deliver this under normal driving conditions? Carry 180 tonnes so 360 tonnes is 2 moves.

Distance (km) = (14 - 4) * 225 * 6 * 1 divided by 360 tonnes = 37.5 km

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Re: Supplying War 2nd edition - vehicle efficiency

Post by Der Alte Fritz » 06 Feb 2017 12:23

Example 3.
During the battle the average consumption is 3,120 tonnes a day. Army has 8 Large Motor Columns, and 10 divisions each with 6 Small Motor Columns. How far can the Army operate away from the railhead?

a) Army: 8 x 60 tons = 480 tons lift, so to move 3,120 tons from railhead to depot will take 3120/480 = 6.5 journey a day
(14 -8) * 225 * (8 x 2 for Large Motor Columns) * 1 divided by 3120 = 7 km

b) Each Division receives 312 tonnes a day. 6 x 30 ton Small Motor Columns = 180 tonnes so 2 daily journeys from depot to Divisional Supply Point
(14 - 2*2) * 225 * 6 * 1 divided by 312 = 43 km

c) Distance travelled by combat units of artillery batteries from firing position to Divisional Supply Point = 20 km

So distance is 7 + 43 + 20 = 70 km from railhead to frontline

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Re: Supplying War 2nd edition - vehicle efficiency

Post by Der Alte Fritz » 06 Feb 2017 12:49

So you can see from these examples in H.Dv.g.90 that the Germans took into account loading times as a major factor as each Motor Column took an hour to load and then another hour to unload with the help of a Supply Platoon. Also they account for differing road conditions and daylight conditions.

Their assumed rate of advance is 15 km/h which relates very closely to the British 10 miles in the hour (14 km) and again drivers are travelling at 50 km/h speed to achieve this with a 10 minute stop every hour for a break, fix minor issues on vehicles, close up stragglers, etc. Traffic slows down the average rate, as do defiles such as built up areas, steep terrain, bridges or other terrain features. If heavy traffic is crossing a road of course this halves the available capacity of both roads.

Another factor to take into account is that our British series of lorry columns comprising 2,400 lorries is 120 miles long at 20 vehicles to the mile. The first lorry is just arriving at the destination after 12 hours and a drive of 150 miles and the last lorry has only been on the road for 3 hours and travelled 30 miles. So the whole transport will actually take 12 + 9 hours = 21 hours.

The capacity of the road itself is close to 2,400 vehicles a day. The only way that this can be increased is to
a) shorten the distance between vehicles - this creates other problems such as concertinaing as well as vulnerability to air attack.
b) increase the load of the individual vehicle. A 10 tonne lorry and trailer combination will still fill up one slot in the convoy compared to a 1 tonne truck. But there does come a point when the road is full to capacity and you need another road.
c) improving the road to remove things that slow down the traffic or to increase traffic control.

Assuming a 10 tonne semi trailer is the largest vehicle and that 4,800 vehicles is the maximum number of vehicles on this road at 45 yards per vehicle (no air attack) then 7,200,000 ton mile is delivered. This is 48,000 ton at 75 miles. Using normal lorries (5 tonne) this is 24,000 a day.

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Re: Supplying War 2nd edition - vehicle efficiency

Post by Der Alte Fritz » 07 Feb 2017 08:25

This was the American pattern at Normandy, they started with 2.5 tonne 6x6 and 6x4 GMC Trucks loaded for road use to 5 tonnes. This proved too little and so they added trailers which increased the load to 10 tonnes but came at a cost as towing trailers uses more fuel and slows down. The British Pocket Book gives a figure of 20 mph cruising speed and only 8-12 miles in the hour. So in 1945 the US Army started using semi-trailers which could both carry the load and maintain the speed.

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Re: Supplying War 2nd edition - vehicle efficiency

Post by Dann Falk » 10 Apr 2017 15:57

Nicely laid out.

I did not know Martin van Creveld "Supplying War" had a second edition; I'm using the 1977 edition, Cambridge Press.

I guess the major difference between Lorry vs Wagon is that the lorry is faster, carries more and consumes a less bulky cargo, (Gas vs Grass).

What stops an army supplying itself over a distance of 1,000 miles? I would say too many moving parts. One WW2 Liberty ship, with one engine, sailing at 12-13 MPH, and a crew of 30-50, sails into port and delivers 10,000 tons of cargo. Lorries and wagons are just too small to go the distance.

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Re: Supplying War 2nd edition - vehicle efficiency

Post by von Shapp » 08 Sep 2017 00:36

Der Alte Fritz wrote:In the second edition of "Supplying War" by van Creveld, in the chapter "logistics in perspective" (p234 in my edition) he discusses the how armies attempt to move forward while supplying themselves and how far they are able to move forward. He makes the point that the theoretical distance for vehicles is never achieved for instance:

a horse drawn wagon 4 horses each consuming 20lb of fodder a day gives a maximum distance before using up its entire payload as 20 X 2,240 /80 = 55 miles of which 120 miles has ever been used in practice ie. 22%

a 5 ton WWII lorry loaded with nothing but fuel could travel at least 5,000 miles before using all its fuel. However at most only 10% of this has been used as armies seemed unable to support themselves more than 500 miles from their bases using lorries so there are greater losses with using lorries than with horses.
My dear Der Alte Fritz, I believe your calculations are slightly off.

20 * (2,240 / 80 ) = 560 is the correct answer, not 55.

Also, which 120 miles has ever been used in practice ie. 22%

is due to the need for the waggon to carry fodder for the return journey and to make the return journey. If you change the equation you posted to read as:

(20 miles per day / 2) * (2,240 pounds capacity / 160 pounds fodder consumed per day) = 140 miles realistic theoretical range.

It comes very close to the 120 miles that Creveld cites; the difference of 20 miles is probably due to the weight of the waggon driver, food, water and bedding for him or his assistant.

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Re: Supplying War 2nd edition - vehicle efficiency

Post by Der Alte Fritz » 08 Sep 2017 10:34

Apologies for the mis-typing of 55 for 560 but other than that this entire section is a quote from the 2nd edition of "Supplying War". Since Van Creveld is simply calculating the maximum distance that a vehicle could travel when using its entire payload as fuel, there is no return journey as he is just calculating the distance travelled. I personally do not agree with his figures for horse-drawn wagons but it is useful as a talking point.

A reading of any of Gerhold's books on horse transport in England in the early C19th uses the report to Parliament from 1830 that studied horse-drawn road transport. He shows that typical road haulage wagons were 6 tons pulled by 8 horses (so 1,680 lb or 762 kg per horse) and that road conditions really did not make much difference to the load hauled. The main factors in reducing the amount hauled were a) gradients, even slight gradients reduced the horse efficiency and required additional animals to be harnessed. b) speed, a horse walks at 2.5 mph and over the course of a day would travel 20 miles and could pull its maximum weight for an extended period of several months, working at 6 days a week and 1 rest day. When Vans (lightweight sprung wagons with large wheels built for speed on turnpikes) were introduced it was found that they could travel at 6 mph (ie. a trot) but that the horses needed to be changed twice as much (ie. half the load hauled per horse.)

The real innovation in increasing the efficiency of road haulage in the C18th occurred in the 1730s and was down to the use of stages - running the wagon 24 hours a day but changing the teams and driver every 8 hours at pre-prepared inns. This meant that the wagon covered 60 miles a day. The other large change was in the breed of horses which mean that over the course of the C18th the pulling power of horses doubled and at the same time the amount they ate fell by a third as bigger and individually stronger horses took over from the smaller breeds.

Reading Hagerman "The American Civil War and the Origins of Modern Warfare" gives an idea of what this meant to military vehicles in the middle of the C19th.
A 4 horse or 6 mule team could haul:
macadam roads - 4,500 lb load plus 5-10 days of grain ration for the horses
solid dirt roads - 3,500 lb -"-
good roads - 2,800 lb -"-
rough country - 1,800lb -"-
which gives us a horse hauling between 1,125lb and 450lb and 2/3rds for a mule.

The point to note is that the military wagons are hauling less than the civilian wagons to leave them spare capacity to march at a higher speed or to cope with unexpected gradients and because the military horse ration might be considerably less than the civilian one which was high quality and regular.

With regard to the demand for forage or provender from the horses, authors such as John Lynn lump all the provender in together whereas there are two distinct types. Hard feed or grain such as oats and barley are a foreign crop and have to be brought in from regions that grow it while fodder such as hay and straw is universal and could be collected in the area through which the army was marching. In most cases hard feed had to be supplied just as the men's rations (and in many ways was very similar in size and weight to flour) were but the situation regarding fodder was more complex. The mass of the army (particularly the artillery and baggage wagon teams) could be supplied through collecting in the local area for a period and at the right season of the year. Units outside the camp of the army such as cavalry units and the supply units could graze their horses at night time in the local fields. The problem of fodder became acute in the Spring and Winter when the grass was not growing or if an army stayed in the locale for an extended period of time, in which case, fodder had to be brought from a depot at some distance. There are plenty of instances, Frederick the Great, Wellington in the Peninsula, Shermans Atlanta Campaign, right up to the Soviet Army Regulations of 1936 which show that armies gathered fodder locally. Shermans comment that a horses required 20lb of provender a day is an example of a working average as the regulations stated that the ration was 26lb - he is averaging between those period when fodder has to be supplied and the times when it can be gathered locally. This grain ration was 12lb per horse per day to be supplied alongside the men's rations of 4lb. With a Civil War army of 100,000 men and 40,000 horses (cavalry, artillery, baggage train and supply train) the daily demand is 178 tons a day and the horses 214 tons a day or 140 wagons.

What has to be considered is the "Tempo of operations" as until the Great War armies actually moved very slowly and spent considerable periods in camp. When marches were undertaken they were for quite limited periods and from one source of supply to another.
My writings on this for the C18th can be read here: https://www.hgwdavie.com/blog/2017/5/20 ... operations
and for the C19th here: https://www.hgwdavie.com/blog/2017/5/25 ... ailway-age

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