Winds of Destruction

by Peter John Hornby Petter-Bowyer

  In the case of ANFO, the steel containers swell in size, as do the high-explosive containers; but ANFO, having a much slower flame-rate, continues its heaving detonation well beyond case disintegration. An ANFO mix, when confined in a steel container and given a hefty thump by an initiator charge such as Pentolite, ignites spontaneously to generate enormous amounts of high-pressure gas in a heaving EXplosion which forces air outwards from the generated gas bubble. The gas cools immediately, creating a void into which the air flows at supersonic speed, causing an IMplosion.

  Digressing for a moment, the implosion following an atomic bomb blast causes more damage to structure than the initial explosion. In the case of ANFO, explosion and implosion are equally damaging—a double dose of no good.

  The production of ANFO, a commonly used mining explosive, simply involves the thorough mixing of a small quantity of diesel fuel into prilled ammonium nitrate fertiliser. In the beginning we did this with a shovel in a wheelbarrow. Later we progressed to a simple motor-driven concrete mixer for large-quantity production.

  ANFO offered a special advantage. From the start we realised that it would not be necessary to use special ammunition dumps for the safe storage of ANFO bombs. Unlike standard high-explosive units that had to be filled in specialised conditions, ANFO bombs could be stacked in the open and only filled when they were needed.

  Digressing again and returning to the Mao Tse Tung ‘ground cannon’ mentioned in conjunction with the CT ‘air ambush’ system, I decided to test this ‘cannon’ using ANFO as the explosive. A one-metre round hole was dug to a depth of one metre. At the base we placed a 20kg charge of ANFO then filled the hole with rocks.

  Kutanga Mac places the final rocks watched by, Bev, with head down and Ron Dyer second from right.

  Waiting for the explosion and ensuing rockfall.

  The project team was over 1,000 metres away when the ‘ground cannon’ went off with a dull thunderclap. Whilst the rocks remained close together, their rapid passage up to around 1,000 feet above ground was obvious. Thereafter we could see nothing of individual rocks that soared on to greater heights. We watched the ground ahead for ages waiting for the rocks to land but neither saw nor heard anything. I was heading for my vehicle when a peculiar sound, which I can only describe as something like static electricity, developed all around. Everyone dived under vehicles in time to avoid the rocks that came crashing down.

  Used in multiples around airfields, this crude device would have been devastating to enemy paratroopers and ground-attack fighters. Fortunately however, there was never a need to employ Mao Tse Tung’s crude but effective ‘ground cannon’.

  Further static 500-pound ANFO trials were conducted before making a direct comparison between an imported 1000-pound bomb and an ANFO unit of equivalent mass. For this we acquired specially bred white guinea-pigs with black ears. They were placed in wire-mesh cages, set in deep holes (to protect them from shrapnel) next to which pressure pots and pressure discs were laid in a line at five-metre intervals from fifteen metres outwards to fifty metres from point of detonation.

  Inspection the hole from the small charge of ground cannon trial. PB 2nd from left, Bev 5th with hand over eyes and Kutanga Mac in dark shirt 9th, view the large hole made by the small ANFO charge of our ‘ground cannon’ test.

  The imported bomb explosion had no noticeable effect on the pressure pots and pressure discs beyond fifteen metres. In the fifteen minutes it took us to get to the test site, every guinea-pig, including the two at fifteen and twenty metres, had recovered from the big bang and were munching away at the feed in their cages.

  Following detonation of the ANFO unit, we rushed back to the little creatures with a forensic pathologist in tow. I had persuaded this medical specialist to assist us in our ANFO tests by examining the bodies of snakes and frogs we found on the surface following every single ANFO detonation. All these cold-blooded creatures, though dead, appeared perfectly normal until dissected. Over-pressure had destroyed their lungs and other vital organs without any damage to outer skin. The frogs, which lived more than one foot below surface, were always found on top of the powdered earth, lying belly up.

  At the 1000-pound ANFO detonation site we found every guinea-pig hunched up, motionless and covered in thick fine dust. Those at fifteen, twenty and twenty-five metres from blast had perished through overpressure. Those at thirty and thirty-five meters had perforated eardrums; the remainder recovered quickly enough but would not eat for more than ten hours. The pressure pots within twenty-five meters suffered distortion with permanent set and satisfactory over-pressure readings extended out to thirty-five metres.

  The guinea-pigs that survived the ANFO blast were kept in a large pen separate from those that had been subjected to the imported bomb blast and Kutanga Mac looked after these little fellows better than any private home could. For reasons we never established, the guinea-pigs in the ANFO pen grew larger than the others and became enormously fat. The two deaf animals were the happiest, fattest and hungriest. All were eventually found good homes.

  Our first ANFO bombs weighed 450kg, which was equivalent to the imported 1000-pound bombs. Canberras and Hunters released these in a series of tests. Although the tests themselves were successful, we were not at all happy with the loss of energy evidenced by large craters in the ground where they detonated.

  Operational considerations clearly identified Hunters as the main user of high-pressure bombs, so we turned all attention to fighter/bomber style steep-dive (sixty-degree) profile attacks. To maximise blast effect each bomb was fitted with a one-metre-long proboscis to ensure airburst. To minimise energy losses downward and upward, and to maximise ground overpressure, simultaneous initiation of Pentolite booster charges at the front and rear of the ANFO charge resulted in a very satisfactory ‘squeeze’ effect. In doing this, each bomb flattened everything around the point of contact and no energy was lost to punching out ground craters. The entire tailpiece was usually found at the centre of detonation proving that almost no energy was going skyward.

  Golf bomb.

  During early tests each pair of bombs landed close together; so we decided to improve the ninety-metre diameter bush-clearing effect by retarding one bomb to force it to fall short of the unretarded one. Spring-loaded metal paddles were used initially but these were clumsy and inefficient. They were discarded as soon as we learned how to absorb the high shock loading involved in deploying our own designed and manufactured drogue chutes. The drogue chutes worked well and forced the retarded bomb to fall about thirty-five metres short of the streamlined unit. From then on a pair of ANFO bombs gave a bush flattening-pattern ninety metres wide by 135 metres in the line of attack.

  450kg Golf bombs were cleared for operational use in March 1977. Testing continued for some time thereafter, resulting in the ANFO bombs being upgraded with double steel cylinders sandwiching thousands of pieces of chopped 10mm steel rod to give lethal shrapnel effect beyond the over-pressure boundaries. Although officially termed 450kg HP bombs, the project title stuck and everyone knew them as ‘Golf bombs’.

  Cavalry Fireforce

  IN MARCH 1977, OZZIE PENTON asked for my temporary release from project work to conduct recce training camps for all PRAW crews. To make this manageable and to minimise disruption to my own work, I arranged for four separate five-day camps to be run in March, April, May and June. I chose Marandellas Airfield for the first recce camp and had Cocky Benecke, Francois du Toit and Norman Maasdorp along to assist me. Francois had resigned from the South African Air Force to join our force and was keen to get back to air recce work.

  John Blythe-Wood, as lead K-Car pilot operating out of Mtoko, had been having a run of first-class successes in which he had twice called for Canberra Alpha bomb strikes. My wish was to find a target for John’s Fireforce in the hope that he might use Canberras again because I had not personally witnessed an Alpha bomb strike from the air.

  On 22 March I found a plum target and counted thirty-eight
CTs moving out of a their well-defined base camp. Unfortunately the Mtoko Fireforce was not available, so the Grand Reef Fireforce, led by Mike Litson, responded instead. An agonising fifty-five minutes elapsed before the Fireforce came into view. I put Mike onto the campsite first for orientation purposes and, considering the long delay, it was fortunate that my guess at where the CTs might be found turned out to be correct. In the action that followed, sixteen CTs were killed, one was captured unhurt and seventeen escaped, most having been peppered with 20mm shrapnel from the K-Car.

  Although I read all the Air Strike Reports in Air HQ it was not the same as seeing for myself the existing problems of having too few Fireforces. They had to cover many thousands of square miles in which ever-growing numbers of CT groups were operating. I wondered if employing a new approach might offset the shortage of Fireforces and allow air recce finds to be less dependent on their availability.

  PRAW recce training camp, at Marandellas Airfield. Names that appear in this book are: Standing: Ray Haakonsen 7th from left, PB between catering ladies, Hugh Chisnall (bald next to blonde lady—he was the pilot who found John Smart’s missing helicopter). Squatting: Phil Haigh and Francois du Toit (left), Sarel Haasbroek (2nd from right). Sitting: Cocky Benecke (centre) Hamie Dax (right).

  Lieutenant-Colonel Tony Stevens, commander of the horse-borne troops of the Grey’s Scouts, listened to my ideas of using his Grey’s Scouts as an alternative to the heli–borne Fireforce. He leapt at the opportunity and we made plans to give it a try the next day in the St Swithins Tribal Trust Land. This was to have a force of twenty horsemen moving along a predetermined line at a gentle walk whilst I conducted air recce five kilometres on either side of their line.

  I found the force immediately I arrived at the appointed RV and the sharp accent of the Grey’s Scouts major made me realise he was Australian. He confirmed the line he would ride and I confirmed the procedure I would adopt. Not ten minutes passed before I found a base under trees on high ground, commanding an excellent view of surrounding grasslands in which were some bare maize fields, very few trees and three small villages.

  My 1:50,000-scale map showed a shallow depression running west to east 500 metres to the north of the base but this was not obvious from my recce height. I had no knowledge of horse-borne tactics for approaching targets unseen. Having given him the relevant grid references, I asked the major’s opinion on the cover the depression would afford him. He assured me he could get to a position 500 metres north of the base without being seen and said he would call me across two minutes before his arrival there. At the time I was about five kilometres away, having maintained a routine orbit line, but I could see the horses clearly even when they passed through tree cover. The speed at which the horses covered the ground was very impressive.

  When the force turned right to move directly towards the base, ten pairs of horsemen surged forward, galloping at different speeds to place them in a wide crescent before the centre horsemen came to a halt and dismounted. In no time there were ten pairs of men surrounding the base site. The nearest troops to the base were about 150 metres away. No more than ten minutes had passed from finding the base to having it surrounded by men who had dismounted to commence a cautious approach towards the base.

  Disappointingly, the base was empty, having been vacated about two hours earlier. Nevertheless it was clear to me that this silent force would have achieved complete surprise and total encirclement. Had there been serious opposition, a status quo could have been maintained for as long as it took for a regular Fireforce to reach them.

  Unfortunately, the success of the trial ended abruptly. I had continued searching for another target when I saw smoke rising from two villages close to the base. I could not raise the major on radio so flew back to see what was going on and was horrified to find all huts of the third village in the process of being torched. My presence overhead brought the major back to his radio set and we entered into a very heated exchange. The major maintained that the locals needed to be punished for feeding the CTs. I objected and insisted that these same locals, who really had no alternative but to feed CTs, would more willingly support ZANLA following this senseless action.

  I terminated the trial even before a whole hour had passed because I needed to discuss Grey’s Scouts’ procedures and attitudes with Tony Stevens. He was very apologetic about his Australian major’s actions and assured me that appropriate action would be taken. Nevertheless, Tony was delighted to learn that, in my opinion, Grey’s Scouts could be employed in a Fireforce role in support of air recce and Selous Scouts. Regrettably I never found another opportunity to pursue the matter personally and the concept was lost.

  Testing American equipment

  BOB CLEAVES RETURNED FROM USA with the equipment I had requested for field trials. The gyro-stabilised binoculars were mind boggling on the ground. Superb magnification and a rock-steady image, no matter how much one trembled, made them a perfect aid for game-viewing. In the air, however, the binoculars were only useful to inspect selected points during a gentle orbit. The moment one tried to keep an eye on a point whilst in forward flight, even at 4,000 feet above ground, the rate of scan induced precession of the gyro beyond its limits and toppled the spinning mirror.

  This was a great pity because from 4,000 feet one could clearly distinguish between an FN rifle and an AK-47. The only airman who showed any interest in the unit was Sergeant Pete McCabe who was also the only man I knew who used standard binoculars in flight. How Pete managed to see anything through binoculars when flying in helicopters that vibrated so much I do not know; but he was as successful with them as he was firing his machine-gun or cannon.

  Having been designed for security surveillance, the night-vision unit worked wonderfully on the ground. In flight, there were too many problems in trying to match what one could see through the bright night-vision unit with one’s dimly lit map. Only regular pathways through open ground could be seen but all hills and bush lacked any perception in depth.

  The US bulletproof vests were better than the few we had previously acquired from some other source although one of these had saved Vic Cook’s technician. The American vests were subjected to destructive testing from our own FN rifles and a variety of communist rifles and machine-guns firing 7.62 mm ammunition. Though the vests gave no protection against armour-piercing rounds they were considered both suitable and essential for Fireforce aircrew and airborne Army commanders. Thanks to Bob and his US contacts, our order for these life-saving items was met and became standard operational wear for aircrew and airborne Army commanders. Many men owed their lives to these vests.

  I was keen to develop better ceramic platelets to produce our own protective vests and to use as protective cladding on helicopter engines. Doctor Patrick Grubb of the University of Rhodesia took up my challenge and succeeded in producing ceramic platelets that gave full protection against armour-piecing rounds fired from 100 metres. He was still negotiating with a manufacturer to produce them on a large scale when our war came to an end. For his efforts Pat Grubb was given clearance to use the technology for his own benefit but, so far as I know, this was another successful Rhodesian development that faded to nothing.

  COMPOS established

  FROM THE MID 1960S UNTIL MARCH 1977, overall control of operations vested with the Operations Co-ordinating Committee whose secretarial arm was the Joint Planning Staff. The OCC still comprised the Commanders of Army and Air Force, the Commissioner of Police, and the Director of Central Intelligence Organisation. The Chairman of JPS acted as secretary and he was responsible for the execution of all joint service decisions and directives emanating from OCC, whereas individual heads handled single service matters. Because service in the top posts of the Army and Air Force was limited to four years and the Police to five years, only Ken Flower of CIO served continuously on the OCC.

  Under OCC were the Provincial Joint Operations Centres, JOC Hurricane (Bindura), JOC Thrasher (Umtali), JOC Repulse (Fort Victoria),
JOC Tangent (Bulawayo) JOC Grapple (Gwelo) and JOC Splinter (Binga). At each JOC the Provincial Head of Internal Affairs was a permanent member. Other government departments, such as road and telecommunications, could be co-opted on an ad hoc basis. Below each JOC there were two or more Sub-JOCs. For instance, under command of JOC Hurricane were Sub-JOCs Sipolilo, Centenary, Mount Darwin and Mtoko.

  At no level was there a recognised supremo. Chairing of JOC meetings was done in rotation between the Army, Air force and Police. This style of command and control expected “Reasonable men to act responsibly in co-operation with one another”. So long as we were experiencing total successes against ZIPRA and ZANLA in the years prior to 1974, the system worked remarkably well. However, by late 1976 it had become clear to everyone that ZANLA was gaining ascendancy and that Rhodesia’s resources were being stretched to the limits. It was also clear that, whereas ZANLA was working to a specific strategy, JOCs and sub JOCs were doing their own thing in the absence of clearly defined political and military strategies upon which to formulate plans and tactics.

  Considerable enterprise was shown at every level in all services; but these unco-ordinated initiatives were not all good for the country. In the absence of a supreme commander with a staff of top line planners to give executive direction, it was not surprising that strong initiatives by men and units, all driven by frustration and the will to win, too often achieved negative results.

  From my viewpoint, the most obvious of these was the negative mindset of many Army and Police officers towards the Selous Scouts, even though the Scouts were directly responsible for the majority of our internal counter-insurgency successes. Much of this arose from a lack of understanding of pseudo operations, and more so because Selous Scouts had to fight red tape and prejudice for everything they needed in terms of men and equipment. Ron Reid-Daly’s fiery character and deep-seated secretive manner did little to help this situation.