A bad day at the office – perspective on the HMS Ambush collision

On 20th July 2016, HMS Ambush collided with the merchant ship MV Andreas, just off Gibraltar. At the time Ambush was conducting the ‘Perisher’ Submarine Command Course (SCC) and was under the command of ‘Teacher’ Cdr Justin Codd. After a lengthy independent Service Inquiry, Cdr Codd’s court-martial took place in Portsmouth this week, inevitably attended by a flurry of negative publicity. Here we take an all-around look at the incident.

The incident

On the day of the collision, HMS Ambush was under the control of a student practising controlling the submarine at periscope depth and observing shipping movements. The court-martial found that Cdr Codd was focused on teaching other students and had not made adequate observations of the surface picture himself, assuming the student was safe to proceed. Avoiding action to due to the presence of a small yacht, took Ambush onto a collision course with the merchant ship.

Fin of an Astute class boat

How its supposed to look… close up of the fin of an Astute class boat. This gives an idea of the size and complexity of the vessel, the fin alone weighs 65 tons. One of the Optronic masts is visible with the electronic support measures (ESM) antenna mounted above. Note the openings for a number of masts, the conning position, portable compass mount and the sensor array below.

Ambush suffered a glancing blow as she passed under the merchant ship, with the impact crushing the upper forward part of the fin. One might speculate that the initial contact with the side of the ship pitched the submarine’s bow upward so the transducer on the fore-casing impacted on the bottom of the ships hull. The conning position on the fin was completely destroyed but the most expensive casualty was probably the sensor array mounted below. This is possibly a high-frequency sonar used for under-ice navigation and obstacle avoidance. The Intercept Array Transducer (Hull Outfit 51R) on the forecasing is mounted in a free-flooding, carbon fibre dome and is optimised for detecting active sonar transmissions from warships. This may have suffered some damage as the protective dome was destroyed. Details of the Astute boats are highly classified but the vessel does have many separate external sensors that give them probably the most effective sonar suite in the world today.

The pictures look dramatic but the repair cost a relatively modest £2.1 million. At no time did the damage to the submarine create any danger to the crew or vital systems, including the nuclear reactor as the very tough pressure hull was untouched. Fortunately, it appears the various masts in the fin escaped damage and the main periscope could still be raised an lowered. The bigger immediate concern was the loss of an available SSN for several months. Ambush would probably have been scheduled to complete a patrol somewhere after Perisher course concluded but instead, after temporary repairs in Gibraltar, returned to Scotland on 12th August and she was still under repair alongside in Faslane well into 2017. For a short period in 2017 no RN attack submarines were at sea at all, and the unexpected loss of Ambush only exacerbated the RN’s chronic shortage of boats.

Adapting to new optronic periscopes

Instead of traditional optical periscopes, the Astute class boats are fitted with two CM010 non-hull-penetrating optronic masts. The new electric periscope provides imagery to screens in the control room and has the tactical advantage that it and can be raised, quickly rotated through 360º and then lowered so as to minimise the time the periscope is exposed to possible detection. The recorded high-resolution imagery can be analysed at leisure with the submarine safely out of sight. The Astute class have two masts, one combining a high-definition colour television (HDCTV) camera and a thermal imager, the other has an HDCTV and image intensification camera. The CM010 also features 3-axis stabilisation which gives a much more stable and clear picture, even if the boat is pitching or rolling when at periscope depth in rough seas.

The first optronic periscope used by the RN was trialled aboard HMS Trenchant in 1998 but, for the majority of submariners commanders, they will have spent most of their careers using traditional periscopes. Although the new optronic mast clearly offers great advantages, to realise these benefits and operate safely requires a new mindset for the command, especially in confined waters. Evidence given at the court-martial suggests that procedures involving the use of this new technology may have partially have contributed to the accident. Cdr Codd had been involved in writing the manual for the use of optronic periscopes in RN submarines but after the collision, he has been assisting in developing revised procedures.

Many will wonder how a boat with sensors that can potentially detect vessels hundreds of miles away, managed to collide with a ship in broad daylight. When the periscope is not raised a submarine is blind and must rely on sonar alone. In busy shallow waters with high ambient noise, the sonar picture may become confused. Students are taught to use the periscope as infrequently as possible but in this case, the movement of the merchant ship went unobserved, clearly human error.

Being the best of the best

Without discussing the full details of the SMCC, it is safe to say the course is arduous for both the students and ‘Teacher’. The course is run over about 4 months and includes a significant time ashore using simulators. It is the final ‘cockfight’ phase where the student is put in command of a submarine at sea and is expected to perform very demanding tasks requiring exceptional situational awareness and quick decision making under pressure. The course was near to completion when the accident occurred and fatigue may have been a factor.

Only the very best submarine commanders get selected to become ‘Teacher’, Perisher is also recognised as one of the toughest command courses run by any navy and is foundational to the high reputation of the RN submarine service. Cdr Codd had an outstanding career until the time of the incident and this was recognised by the court. “You have, save for this incident, an exemplary record. It was more in the nature of a momentary aberration than a careless attitude,” said Judge Advocate Robert Hill.

HMS Ambush’s captain Cdr Alan Daveney was also on board at the time of the accident. When conducting Perisher, the CO is in a delicate position, still ultimately responsible for the boat but delegating control to ‘Teacher’ who is the same rank but has more seniority and experience. Theoretically, he could intervene if he was in the control room at the time and considered the boat to be in danger. It is interesting to note that Cdr Daveny has not been court-martialled, although the incident will not be career enhancing.

Learning from mistakes

Despite the embarrassment for the navy and a £2.1million repair bill, Cdr Codd was not sacked as ‘Teacher’, severely reprimanded or dismissed the service which has happened to officers in similar cases in the past. His punishment will be a loss of a year’s seniority and this will have a small impact on his pay. This is not a case of the RN being over-lenient but the court recognising a good man made a momentary mistake, he was found not to have deliberately ignored an obvious threat or taken any unjustified risk.

A Commander in the RN (OF-4) typically earns between £70-80k depending on length of service, but all submariners get extra pay which may add at least another 10% on top. Considering the incredible responsibility carried by an officer in command of a nuclear submarine, pay levels are very modest in comparison with similarly responsible such jobs in the civilian world. The nature of naval appointments cycle means that typically after two years or so as one down from God in command of a submarine or warship, most officers will suddenly find themselves ashore behind a desk and some will never go to sea again. This can lead to frustration and many good officers leave the navy at this point. Having invested enormous expense in training and having attained vast experience, the navy is reluctant to lose men like Cdr Codd and continue to utilise his talents. He will have to live with this blemish on his career for the rest of his life but has persevered and continues to serve. In the world of aviation, a culture of openness and transparency surrounding accidents and near-misses has helped improve flight safety.

Punishing people for making mistakes by sacking them, does not always improve matters. In cases where there is not gross negligence or misconduct, it is perhaps better to build on the personal experience gained to improve procedures.

Pushing the limits

The RN submarine service has not achieved such a reputation for success without a measure of aggression and willingness to take risks. Modern simulators enhance training and can reduce the amount of time needed at sea but there is no substitute for the real thing. The RN’s reduced fleet leaves little option but to conduct training using a submarine worth more than £1Billion and ties up one of the 2 or 3 available boats. Smaller conventional boats would perhaps be a less risky and more economical platform for submariner training but obtaining some for the RN is unrealistic when even getting 7 Astute boats is now in doubt. The SMCC is run in conjunction with the Dutch Navy (officers from other NATO navies can also take the course) and sometimes conducted aboard their small conventional Walrus class boats.

Perisher students must continue to be pushed and take risks operating in confined and congested waters. The possibility of accidents remains inherent in all naval operations and preparation for combat requires constant and realistic practice. Training accidents are experienced across the board, for example, the RAF has suffered at least 50 non-combat related losses of Tornado jets since 1983. The British Army suffered 88 fatalities during training exercises between 2000 – 2015. Applying the lessons and efforts to eliminate future mistakes must be a high priority but forces training will always be a difficult balance between safety and realism.

Leaving Gibraltar after temporary repairs


Main images by kind permission: David Parody.