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.

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.

Main images by kind permission: David Parody.
Related articles
- Senior Royal Navy commander pleads guilty to crashing £1bn nuclear submarine (Telegraph)
- Perisher – the ultimate challenge for students… and Teacher (Cdr Ryan Ramsey, former Perisher Teacher)
- Traditional periscope replaced on submarine HMS Astute (BBC)
When the USS Dolphin suffered a severe flooding accident, the US Navy came to a similar determination – no one was fired. One the sailors (an E-6 at the time, later a Chief Petty Officer) received a medal for his actions. http://www.navy.mil/submit/display.asp?story_id=5397
That was unusual, but the right thing to do.
There is more to come.
The senior students involved in the training have gone on to ‘pass’ the Perisher course.
We can look forward to future collisions and mealy mouthed defence of incompetence masked by odes to service and duty.
I guess with all your Naval or military service coupled with years of expertise in command of a nuclear submarine you would have done better ??
What would you know?
Shocker out Islamic state resident slandering and badmouthing the rn. Why don’t you go blow yourself up?
Lol
According to the STRN crowd, I’m either a Islamist or a Commie Putin bot. You guys need to compare notes and a decision on which it is. Due to ideological incompatibility, I can’t be both!
Let me tell you, mate, that you act like both and you probably represent both! Your treasonous talk echoes everyone that hates this country and the Western world.
No, you’re the allocated troll from Momentum. Look guys, you fall into his wide open trap every time. Just ignore every one of his posts as if he doesn’t exist and then he has no purpose and will be rendered harmless. This is a site for those who support the RN, therefore Iqbal is clearly here as a disruptor. Stop engaging and he will be reallocated to where he can do more harm and we can get on with our thoughts on how to Save the Royal Navy.
and remind me what submarine you served on????
seems to me that you are a desk bound twonk who thinks he understands naval warfare and the culture of acceptable risk which is inherent to success
if you have nothing to say thats worthy of debate then please return your head to the dark space between your Gluteus Maximus
Oh here we ago again, more troll like baiting from the bottom end of the food chain.
Hahahahahahahahaha. You just make me laugh!! We say this every time, but you clearly dont have a clue as to what you are on about.
The correct term is plonker. To be a wanker you have to get it up!
The submarine fleet is streached beyond breaking point. The SSN fleet is being asked to keep tabs on the Russians, protect our SSBNs, protect our carrier group and perform training, with too few boats. Any incident, accident or breakdown therefore has a devastating knock on and it is totally unacceptable that a training accident results in a complete removal of such vital front one capabilities. That is the streached beyond breaking point made real and not just scare mongering posturing to try and make a point. That is a dereliction of the government’s duty of care to protect this country above all other duties.
Can we therefore still just accept that we will not get anymore SSNs and/or SSKs to help plug this gap? In reality SSKs would supply relatively cheaper alternatives to training boats, first command coastal platforms and special forces insertion.
So what’s the solution? First the Trident successor programme has to transfer to central funding. Second that released funding to be spent on our real life deterrent, extra SSNs and a few SSKs to release SSNs to the deterrent role.
Why am I referring to deterrent when discussing SSNs? Because they are the assists the Russians actually worry about and that is a true deterrent.
The Russian naval threat is being overstated.
If the Soviet Union couldn’t launch an opposed landing in Britain during the height of its power in the Cold War, Putin’s Russia certainly won’t.
As for the Russians sailing close to our waters and protecting sea bed cables, one is ‘friendly diplomacy’ to which we should respond in kind at NATO level and the other requires diversifying cable networks, building resilience and relying on the good fortune that most of the network is very remote and cables are protected by armour. We need maritime defence systems eg. Patrol boats and processes in our home waters and not more large offensive vessels. Thankfully the Russians are reliant on the same cable network.
You really are confused. First you question the competence of our crews then you want more patrol boats, which would be crewed by the very same people. And nobody except you mentioned and opposed landing. Just because Russia can’t invade the UK does not mean they pose no threat.
You really do froth and drool don’t you, stop eating cat litter and clean your teeth, your breath stinks.
You only have to look at the number of minus votes you’ve got to realise how pathetic and childish your remarks are!! Your perception equals that of a child!
Steve: ‘You only have to look at the number of minus votes’.
Well d’oh genius. STRN and its posters only represents a niche part of the right wing spectrum of the population and politics.
Most discussions on STRN come down to funding and I think my views better represent both moderate right and left. You’ll note that neither the party in government or opposition sees the Russians as enough of a threat to hike up defence expenditure.
A great article and one that has structure and balance.
Everyone makes mistakes in life and sometimes those mistakes are significant. What this article deals with very well is the fact that all the simulators in the world cannot replace the real thing.
One thing I would say is that with 2optical masts on board and 2 captains – perhaps in future 1 concentrates on safety using one of the masts and 1 concentrates on teaching using the other mast.
I understand this is an advanced course, but maybe this is a solution.
All in all I think the RN have managed this well and the reason for all the hype is that it is so unusual which is testament to the overall success of the RN’s processes.
Very true, well put.