The incredible story of merchant ship transformed into an aircraft carrier and accidentally sent to her destruction
Modelling the Argentine Exocet Attack of 25th May 1982
The following is an evidence-based assessment of how the Argentine Exocet attack on the British Carrier Battle Group came about and unfolded.
Overview: <This page>
Detailed Evidence-Based Assessment
On the 25th May 1982, two experienced Argentine Navy pilots launched a long-range surprise Exocet anti-ship missile attack on the British Task Force with the intention of sinking one of the two deployed British aircraft carriers and ending the Falklands War. They came within seconds of succeeding.
This is what happened:
The Argentines picked the 25th May, their National Day, to use two of their remaining three French-built air-launched Exocet missiles to mount what they hoped would be a decisive strike against Britain’s two deployed aircraft carriers, Admiral Woodward's flagship HMS Hermes and HMS Invincible.
Unbeknown to British intelligence, the Argentines had been able to adapt their French-built Super Etendards for in-flight refuelling from an Argentine Air Force Hercules tanker aircraft.
The Argentine pilots flew in at low level to avoid radar detection then popped up twice to try and locate large carrier-sized targets with their 'Agave' aircraft radar.
When they switched on their radar, they were spotted, first by Exeter and then by Ambuscade.
On the second pop-up, the pilots detected one small radar target with two large targets behind and no evidence of British countermeasures.
The bearings and distances of ships, aircraft and approaching Exocets plotted out as part of research carried out by Dr Gordon Brooks revealed that the three targets found by the Argentines were most probably the small frigate Ambuscade with the much larger Hermes and Conveyor behind.
As it turns out, Ambuscade and Hermes were also along the same line of sight which led the Commanding Officers of both ships to think their ship was the target.
Hermes was the longer, wider, taller, and bulkier of the two large vessels and all indications are that the pilots correctly selected her as the Exocet target, rather than Conveyor or Ambuscade (as was thought at the time).
Once the Exocets had been detected, the captains of the British carriers followed the latest MoD advice and turned their ships towards the missiles to minimise their radar profiles and protect their engines.
Both Ambuscade and Hermes fired chaff to try and divert the missiles from their track, the sets of decoys dispersing to the NE in the strong wind.
When, some five miles out from Hermes' original position, the Exocets turned on their homing radars, they may initially have been distracted by chaff from either ship. But, by the time the missiles passed astern of Ambuscade, they must have discarded this false target, because they appeared to look for a new one. Directly ahead they now had Hermes emerging bow-on from her chaff blooms.
David Bass, one of the flagship's lookouts, later told his story to the press(1):
"I saw this white-hot glow on the horizon. I shouted a warning to the bridge. Although I had never seen an Exocet, I knew what it was. I was shaking and things were flashing through my mind about my family... The missile was coming towards Hermes. Suddenly it bore to the right and hit the Atlantic Conveyor. She went up in a big pall of smoke."
As observed by numerous witnesses on the flagship's bridge, the Exocets headed straight for Hermes' bows before veering away to their left at the last moment.
Seconds later, the missiles slammed into Conveyor's port quarter stopping her engines and spewing their burning propellant through her open decks full of flammable cargo.
Conveyor quickly turned into a raging inferno. Crew cut off on the front flight deck above her magazine full of cluster bombs were rescued by her returning Wessex helicopter. After losing the fight against the fires, other crewmen clambered down broken ladders from burning decks to take to the water and the few accessible overcrowded rafts.
Twelve of Conveyor’s crew, including Captain North, died that night. Ten of Conveyor's twelve helicopters were also lost along with all the stores on board. The subsequent lack of helicopters forcing the Marines to Yomp to victory. A terrible tragedy had occurred but a far greater one had been averted by the Exocets picking Conveyor over Hermes as their final target.
Analysis: Why did Conveyor Turn the Wrong Way?
Like the two carriers, Conveyor was supposed to be turned end-on to any Exocet threat, in her case by pointing her stern towards the missiles. This was so she presented the smallest possible radar image when the missiles started looking for aircraft-carrier-sized targets in their 'kill zone'.
It was hoped any incoming Exocets would pick large chaff decoys sent up by warships in the area instead.
In order to turn her stern to the Exocets, Conveyor's watch officer would have needed to know the bearing on which the missiles had been detected so he could plot a reciprocal course. But no such conversation occurred. Instead, Hermes instructed Conveyor to immediately turn to port and steer the course 040°. Unfortunately, this heading placed Conveyor side-on to the missiles highlighting her as just the sort of large carrier-sized object the Exocets were looking for.
As part of his research, Dr Brooks consulted with decision-making witnesses (including Admirals Woodward and Middleton) and technical experts in order to try and work out why Conveyor seemed to have been turned the wrong way.
Four possible explanations emerged from the discussions:
a) Hermes' intention had been to turn Conveyor downwind to hide her amongst chaff from other ships
This is a known group manoeuvre where all ships sail downwind at approximately wind speed. Chaff launched from the ships draws the Exocets away.
Problems: No other ships were known to have turned downwind; Conveyor would have taken two minutes to turn onto 040° and therefore wouldn't be making any progress along that course by the time the Exocets turned on their homing radars; The course 040° was 15° off the wind direction as measured on board Hermes.
b) An attempt was being made to get Conveyor out of the area the Exocets were going to scan for their target
As for a), Conveyor wouldn't have actually made any progress out of the Exocets' 'kill zone' before the missiles arrived.
c) Conveyor was deliberately being used as a spare target, a sort of hard chaff (Chaff Sierra)
No one familiar with how the task force operated at the time believed Conveyor had been expended as a spare target.
The question only arose because Admiral Woodward had explained in his book of the campaign ('One Hundred Days') how he’d set up two large merchant ships as dummy carriers as well as a defensive screen of chaff-carrying auxiliaries west of the carriers. He’d also written that he'd been prepared to lose a tanker or a big merchant ship rather than a carrier. On being asked about this, he was absolutely clear that he would not have authorised turning chaffless Conveyor into danger.
On being shown the evidence for Conveyor having been turned the wrong way, he agreed it must have happened, but added that if he'd known about it at the time he would have countermanded the order. As far as he was concerned, Conveyor should have been turned end-on. The given course of 040° made no sense to him.
Lin Middleton, the then commanding officer of Hermes who'd been in the flagship's operations room during the attack, was equally surprised to hear Conveyor had been ordered onto 040° instead of being turned end-on and could think of no explanation for it.
This all seemed to point to a low-level error or misunderstanding no one realised had occurred - the final explanation:
d) Conveyor was accidentally turned the wrong way.
In order to work out which way to turn Conveyor, her watch officer would have needed to know that the Exocets had been detected on a bearing of 310°. He could then have worked out the reciprocal course of 310-180 = 130° Conveyor needed to steer to put her stern to the missiles. Conveyor was on course 170° when the missiles were detected, so he would have needed to turn her 40° to port to put her onto the safer course of 130°.
As the tactical officers on Hermes had all the information about ships' courses and movements at their fingertips and there were only three minutes to complete Conveyor's turn before the Exocets arrived, it might have been decided simply to pass Captain North a direct manoeuvring order rather than leaving him to work things out. Maybe, in the heightened tension of ship-killing missiles heading directly for Hermes, the intended instruction to turn Conveyor to port 40° ended up being transmitted as an order to turn the merchant ship to port onto course 040°. If so, everything would have initially looked in order. Conveyor would have turned to port but then have gone round too far.
If the correct instruction had been passed and Conveyor had put her stern to the missiles then she probably would not have drawn the Exocets onto her, leaving them to endanger the thousands of personnel on Hermes, the outcome of the war, and possibly even confidence in Margaret Thatcher’s government.
Overview: <This page>
Detailed Evidence-Based Assessment
(1) Glasgow Herald, 27th July 1982