Appendix 3: Some Lessons from Operation DICKENS
This appendix summarises some of the lessons of operation DICKENS. It amplifies those described in Chapter 15 and adds fresh ones omitted from the discussion there as being of rather technical interest.
(a) Air Bombing:
This section and that following it are derived mainly from Training Memorandum No. 5 issued by Allied Force Headquarters on 14 June 1944 and based on the reports of the Air and Ground Commanders.
(i) Heavy bombers should not be used in close support when an adequate tactical air force is available. Because of its greater experience in this kind of work, the aircraft of the Tactical Air Force gave a better performance, as to both timing and accuracy, and produced better results than those of the Strategic Air Force. Air bombardment by heavy bombers is not sufficiently accurate for general use in the tactical area of land battle.
(ii) When it becomes necessary to employ heavy bombers in close support, the following precautions to ensure accuracy should be taken: When practicable, bombers and navigators of leading aircraft should reconnoitre the target from the air previously; bombing altitudes should be specified (there was a tendency to bomb from too high); the run-in should, if possible, be along the line of the forward troops rather than at right angles so as to prevent casualties from ‘shorts’ and to save cratering on the approaches to the town from the Allied side; intervals between the waves of bombers should be shorter, especially when the wind is strong enough to clear the smoke from the target quickly, since the intermittent attack gave the enemy appreciable periods of rest.
(iii) An unmistakable artificial landmark, such as smoke, would assist all aircraft to identify the target, particularly when the approach is made from widely scattered points. (Opinion of the Ground Commander.)
(iv) In the Cassino attack, some delayed-action bombs would have been useful to penetrate cellars and heavy covered emplacements.
(v) Alternative targets should be designated for aircraft arriving late.
(b) Ground Troops’ Exploitation of Air Bombing:
(i) ‘The follow up of the infantry must be immediate and aggressive, employing the maximum of infantry strength available. The maximum amount of infantry was not employed in this attack, nor was the attack aggressively pushed. Too great reliance was placed on the ability of the bombing to do the task alone’. (From report of Ground Commander.) The first waves must follow close on the artillery barrage, leaving isolated strongpoints and centres of resistance to mopping-up parties.
(ii) Air bombardment alone cannot be expected to destroy strong defences or determined resistance by infantry well dug in, especially in a fortified town like Cassino.
(iii) Debris and cratering hinder the use of tanks and generally delay the attacker. Hence the tonnage of bombs to be dropped must be carefully considered. The report of the Mediterranean Allied Air Force suggested that such heavy attacks on fortified towns were better suited to defensive operations as at Battipaglia in the Salerno battle, than to the opening blow of an offensive, as at Cassino.
(iv) The technique of street fighting needs continued emphasis in infantry training.
(v) Since close artillery support is not possible in attacking a heavily defended town, mortar crews and tank-destroyer crews must follow the assault closely.
(vi) In general, the delay in launching the operation clearly illustrated the disadvantages of relying on air force action as an essential part of an army plan in times of the year when the weather is unfavourable.
(vii) The smooth co-ordination of air and artillery effort showed that when the air force is placed in close support it should be regarded as part of the fire-power available to the army commander.
The following points made among many others in a report by 4 Armoured Brigade on operations between 7 February and 30 April 1944 reflect experience in Cassino:
(i) If armour must be employed in street fighting, a few well-controlled tanks can do all that is necessary.
(ii) In reasonable going, enemy strongpoints in houses and basements can be destroyed by tanks and infantry kept in close touch by a No. 38 wireless set in the tanks.
(iii) Where passage must be made through a defended town, a quick thrust by armour in three waves has most chance of success–the first wave to pass through to prevent the enemy bringing up reinforcements and supplies, the second wave to take up positions in the town from which to engage strongpoints, snipers and grenadiers who might impede our infantry advance, and the third to move in with the infantry in close support.
(iv) Tank crews must be prepared to lay smoke and clear mines and should not rely on close infantry or engineer assistance in street fighting.
(v) In street fighting strong forces of infantry are essential to mop up and occupy all strongpoints as they go through. An early force of infantry should push through rapidly to join up with the first wave of tanks.
(vi) ‘Available air support [in street fighting] should be used to harass enemy artillery during the time our own artillery is engaged on preliminary barrage of the town. Heavy bombing of town area produces craters and masses of rubble which make tank movement difficult and may, as in Cassino, make all streets and routes impassable to tanks’.
(i) Maximum support of the attack in street fighting was shown to be very difficult because of the closeness of our own troops. The defensive artillery fire of the enemy in Cassino was more effective.
(ii) The identification of targets was facilitated by the issue to Forward Observation Officers of marked photographs, showing numbered buildings and groups of houses.
(iii) Our artillery would have been well advised to make a more systematic effort to close Route 6 on the enemy side of Cassino by harassing fire. (General Senger’s comment.)
(iv) The use of air OPs in counter-battery work was an outstanding success.
(v) For the use of artillery in producing smoke see below, Section (f).
(i) The need for a properly designed armoured bulldozer, already evident from the Orsogna battles, was again and even more forcefully demonstrated. In Cassino it was seldom possible to use unarmoured mechanical equipment, and bulldozers drew fire on themselves and on the troops in their locality.
(ii) The use of standard types of mine detector in clearing large numbers of non-metallic mines was shown to be impracticable under assault conditions. Flail tanks or mine gapping charges were necessary.
(iii) The erection of Bailey bridges in full view and within close range of the enemy was expensive: some less conspicuous form of assault bridging was sought.
(iv) Closer liaison between artillery and engineers was believed to be necessary. To give the engineers the protection which they need for special tasks, it was suggested that in certain circumstances the presence of a Forward Observation Officer with a working party of engineers might reduce casualties and save time over the task.
(f) The Defensive Use of Smoke:
These points are derived from a report by Major R. M. Bell, GSO II (Air).
(i) Conditions of ground were difficult and varied. On the hard, rocky ground round the Amphitheatre and in the west of the town, the containers of smoke shells bounced a long way and caused an abnormal spread round the point of origin. On soft, boggy or waterlogged ground, as near the railway station, they buried themselves and produced little or no smoke. Monastery Hill was so steep that more than one screen was needed to blind it.
(ii) Infantry and tanks agreed that the smoke was helpful in enabling them to approach their objectives, but its value varied according to the time of day. It was usually least effective from about noon to 4 p.m.
(iii) Smoke was shown to be a two-edged weapon. The enemy reacted by mortaring and shelling the screened areas; by using Route 6, when blinded to our observers, to bring forward reinforcements and supplies; and by counter-battery fire against guns laying the screen, which, from their regular rate of fire, were comparatively easy for his flash-spotters and sound-rangers to locate.
(iv) The area to be screened must be clearly defined and co-ordinated with the operations of flanking formations. On occasions 4 Indian Division found the screen highly inconvenient.
(v) Adequate warning of the period for which smoke will be required must be given to overcome supply difficulties. Unexpectedly long smoke programmes meant that ammunition lorries had to come forward by day and casualties resulted.
(vi) The smoke screen should be laid as near to the enemy as possible, to cause him the maximum inconvenience and to deny our troops the minimum of observation. This was not always remembered.
(vii) To reduce wear on barrels and damage to recuperator systems, it is essential to rest one gun per troop or arrange for batteries to relieve each other during smoke programmes.
(viii) The generators were not able to screen the bridges effectively all day. Their value was principally to reduce the number of hours in the day when the enemy could shell the bridges by observed shooting. The smoke produced by the generators was superior to that of the guns or mortars but the generators were awkward to handle, they absorbed a large number of men in maintaining a screen, they had to be supplemented by artillery smoke when the wind changed and adjustments had to be made, and their emission points were mortared by the enemy, so that the operators needed good cover.
(g) Emergency Air Supply:
(i) As it was daily hoped that supplies by porter would reach the isolated troops or that they would be relieved, the requests for air supply were invariably made when the aircraft were loaded with bombs and committed to other tasks. The reloading with supplies, the need to brief the pilots again and the packing of the containers often cost valuable flying time. Earlier requisitions were suggested.
(ii) Standard packs with a single type of commodity were not satisfactory. The loss of one such container could have serious results. Hence composite packs containing ammunition, food, water and medical supplies were soon preferred.
(iii) Of the two types of container used, the expendable petrol tank, dropped without a parachute, was suitable only for rations, but it fell more accurately from 50 feet. The padded canvas container, dropped by parachute, was often carried wide by air currents, but it was easier to locate. It was found that the padding could be advantageously replaced by socks, blankets and warm clothing.
(iv) As the troops were isolated for some time and were using local wells, it was found wise to drop radio batteries, rum and water sterilising outfits.