Blog Archives

Over the Counter Medication & Fitness to Dive

Diving Safety Memorandum 09/18 has just been released and provides information on the impact Over The Counter (OTC) medication can have on fitness to dive.  In particular there are issues with Sidenafil (Viagra) and other drugs, which cause a similar effect as PDE-5-inhibitors.  These have been shown to promote the onset and severity of neurological decompression illness (DCI).

Download Diving Safety Memorandum 09/18 for full details


Oceanic Regulators – Worldwide Recall

There exists a possibility for the Oceanic diaphragm style regulators sold or serviced between October 1, 2017 and May 25, 2018 with a new HP Poppet to significantly restrict airflow at low tank pressures (below 500 psi), posing a drowning hazard to consumers. Any regulator with the new HP Poppet must be fitted with the new style.

For further information & instructions on how to have affected regulators rectified visit

Defective Throw Line

During a recent rescue drill, a defective throw line was discovered with a very low breaking strain.  Riber Products Limited (RIBER) who supplied it have identified a batch of 208 throw bags which could be at risk.

To ensure that throw bag rescue lines are fit for purpose they should be opened and checked. In particular:

  • The entire length of the rescue line should be examined for joins or other discontinuities. This can best be done by feeling along the length of the line with bare hands to identify rough patches or lumps.
  • Any knots, splices or other methods of securing the ends of the line to handles, quoits or other parts of the equipment should also be checked for integrity.
  • The throw bag should be inspected and tried at regular intervals and repacked according to the manufacturer’s instructions, as otherwise the line may not deploy freely from the bag when required.

Any throw bag rescue lines found to have joins or discontinuities should be removed from service and the original manufacturer /supplier informed.

Further details can be found in the latest Marine Accident Investigation Branch (MAIB) Safety Bulletin dated Jun 18 (click here)

New Email Addresses for DST

Following the upgrade to MoD Net, the Diving Standards Team have changed their email addresses.  They can now be contacted as below:

Although their currently email addresses still work, it is unlikely that this will continue for much longer so it is strongly recommended to adopt the new ones with immediate effect.

2018 JS Diving Safety Conference – Report

This year’s JS Diving Safety Conference was attended by approximately 90 people and was hosted by the Royal Air Force Sub Aqua Association at RAF Brize Norton.

After the initial welcome and admin brief, the conference opened with an update on BSAC issues from our outgoing National Diving Officer, Sophie Heptonstall.  This was followed by a brief delivered by Cliff Pearn on how to obtain maximum benefit from the ATG(A) funded BicesterLoan Pool and the annual BSAC safety report from Jim Watson.

After lunch, the keynote presentation was delivered by two members of RAFSAA.  Group Capt (Retd) Dave Rae provided a fantastic look at the early days of RAFSAA when improvisation was the order of the day and clubs thought nothing of making their own equipment up to and including boats.   Sqn Ldr Mark Brabon brought us more up to date with an overview of the very successful MALTESE EAGLE series of expeditions which are an excellent model of how to achieve qualifications at scale.


Lastly the new Superintendent of Diving, Cdr Don Crosbie, introduced himself and provided an insight into the challenges he faces in ensuring safety across a challenging array of different diving disciplines.  He also gave his views on many of the issues facing AT diving.

Finally the JSSADPAC took questions from the floor which provided an opportunity for in depth questions.

Copies of all presentations can be downloaded at the links below:

One of the attendees, Tim Gort, has also produced a really detailed summary of the points made by each presenter on his excellent rectotec blog which can be found at this link.


Looking forward it has been agreed that the next conference will be held on 20 Mar 2019 so everyone is requested to keep their diaries clear on that date!



Old Aluminium Cylinders – Warning

Following a number of recent incidents, the HSE have recently issued a warning concerning the risk of catastrophic failure of old aluminium scuba cylinders.  This concerns cylinders manufactured between 1963 and 1995.

The action required is :

  • Check to see if any of your cylinders are manufactured or suspected to be manufactured from aluminium alloys HE30/AA6082 or AA6351. Check for specific alloy-related markings or for a manufacture date (the earliest date stamped on the cylinder) prior to 1995. If you believe that a cylinder may be made from either of these alloys, then you should assess the risk of continued use by considering the cylinder’s age, history of use and previous testing.
  • If you cannot determine the alloy and appropriate information as described in BS EN 1802—e.g., if you cannot easily read markings on the cylinder or if markings are missing—you must remove the cylinder from service, safely release the gas and render the cylinder incapable of holding pressure.
  • If you are unable to confirm that eddy-current testing was performed on an HE30/AA6082 or AA6351 cylinder, remove it from service, safely release the gas and do not use the cylinder until eddy-current testing can be performed.

The full details of the warning can be accessed on the HSE website at

DSM 02-18 – SCUBA Emergency Breathing Systems

Following discussions with HSE, JSSADPAC and at the JS Diving Safety Conference the Defence Safety Agency (DSA) has issued DSM 02-18.  This supersedes DSM 01-18 which is now obsolete.

The DSM can be accessed on the DST website or at the link below:

DSM 02-18- SCUBA Emergency Breathing Systems v.3


2018 JS Diving Incident Reports

The table below contains a sanitised version (no names or units!) of the service diving incidents that have been received by JSSADC in 2018.

18/50During lesson DO2 to a max depth of 13m, two divers were practising DSMB deployments. Whilst inflating the DSMB using an AS source it became stuck open and efforts to stop the free flow were unsuccessful.

The diver with the free flow switched to their buddy's AS regulator and they ascended without further incident. On the surface the BC was inflated orally whilst being supported.
18/49Prior to ascent on a 30m dive, a buddy pair conducted a gas contents check which showed both had 110 bar. As a drill, both divers inflated their DSMBs but the less experienced one took longer to complete this than expected.

Whilst on a safety stop at 6m, it was observed that the less experienced diver only had 30 bar in their cylinder. The diver switched to their pony cylinder and both ascended without further incident.
18/48During a 14m dive in visibility of <3m, two divers become separated. One ascended under the SMB and the other shortly afterwards under a DSMB. Both were recovered safely to the boat.
18/47Two divers descended down a shot which had missed the wreck. Whilst conducting a circular search in low visibility they became separated. They both ascended shortly afterwards and were reunited at the surface.
18/46Whilst conducting a shore based dive, members of an exped noticed a civilian diver (not associated with the exped) unconscious in the water some way off shore. Four divers donned masks and fins and swam out to the casualty where they administered in water rescue breaths. Following this, the casualty was towed to shore which took approximately 20 mins. After this they were cut out of their one piece twinset harness and recovered with assistance from other exped members.

Once ashore, oxygen enriched basic life support procedures were conducted until the emergency services arrived after about 5 mins. From this point forward the expedition members provided chest compressions whilst paramedics conducted other procedures. After 55 minutes a local doctor certified the casualty as deceased and the body was handed over to the police.
18/45Following a dive to 32m, a diver was unable to hold a safety stop and floated to the surface. The diver dumped gas and returned to their buddy where the safety stop was completed fully.
18/44Whilst conducting Boat handling training, the crew of a RIB heard a Mayday call and were requested by the controlling station to offer assistance to a nearby yacht. It was clear that a person on the yacht was having a stroke so they put him on oxygen and conducted observations.

Within five minutes the emergency services were on scene and took over responsibility for the casualty.
18/43On the deco stop of a trimix dive to 44m, a diver switched to their deco gas but experienced a wet breathe. The diver's buddy handed off their deco gas and the dive was completed without further incident.

On the surface, it was found that the diaphrapgm under the exhaust valve was folded back on itself. It is believed that this took place during the entry into the water.
18/42During a dive to 36m, a CCR diver experienced a cell warning. Following a dil flush, the dive was aborted. The cell did not calibrate properly on the surface so was replaced for subsequent dives.
18/41Whilst descending a CCR diver had a CO2 alarm at 3m and the dive was aborted.

Additional grease was applied to the cannister o-ring for the next dive which was completed without incident.
18/40Whilst completing Sports diver training, a diver reported pain during the descent to 10m for the second of two Alternate Source ascents. The dive was aborted and a slow ascent conducted.

At the medical centre, the diver was diagnosed with an ear infection and prescribed pain killers. They did not dive again for the duration of the expedition.
18/39On an Ocean Diver course, a diver completed OO1 without any issues. Later that day during the descent on OO2 they were unable to clear their ears and the dive was aborted. Following a visit to the medical centre the diver was cleared to dive the following day.
18/38During the sheltered water lessons of an Ocean Diver course, a diver complained of pain in their ears. They were seen by a medical officer who recommended no diving for a week.
18/37A coxswain was giving a pre-drop off brief to a group of divers. One of the divers mistook this for the actual drop off brief and entered the water. Fortunately they were able to swim to the shot where their buddy joined them and the dive continued without further incident.
18/36A diver was distracted whilst building their CCR but completed all pre-dive checks including the pos & negs. On exiting the boat they took a breath and ingested a small amount of water. The buddy noticed that the inhalation t-piece was detached from the mouthpiece.

The diver was recovered to the boat without further incident.

18/35On the first dive of a week long sports diver course, a diver reported difficulty clearing both ears on the ascent.

After a week of further trouble free diving, the diver again had problems clearing their ears on a dive to 21m. The dive was completed at a depth of 17m but just before the ascent the diver developed a headache. On surfacing the diver was nauseous, the headache had worsened and they had bloody snot in their mask.

The DDMO was contacted and recommended that the diver was seen by a diving doctor. They diagnosed ear barotrauma and recommended no diving for 7 days.
18/34Following a dive to 29m, a diver surfaced having missed 3 minutes of live decompression. The diver was placed on oxygen and, following consultation with the DDMO, evacuated to the recompression chamber where they were found to be asymptomatic.
18/33During the descent to 30m, a diver felt water ingress in their suit and requested their buddy checked the zip. No abnormalities were noticed and a reduced duration dive was completed. Subsequently it was found that the suit material had failed and the suit was returned to the manufacturer for rectification.
18/32Whilst conducting a sports diver skills lesson, the diver struggled to clear their mask due to problems with sinuses. On aborting the dive and returning to the surface, blood was observed around the diver's face.

The diver went to the med centre which was closed so attended a local hospital instead and also spoke to the DDMO. They were advised not to dive with a cold.
18/31During OO1 on an Ocean Diver course, a diver vomited into their DV shortly after completing the DV ditch and retrieve process. The dive was aborted and the diver vomited a further 2 times whilst they were recovering to shore.

The DDMO was contacted and advised a precautionary visit to the local medical centre. The medical centre was only able to accept the diver 2 hrs later so the decision was made to monitor the diver in situ.

Approximately 45 mins later, the diver informed the SADS that they were feeling chest pains. The DDMO was contacted again and given this update. On the basis of this new information, the DDMO phoned the emergency services and requested an air ambulance to take the diver to the nearest A&E hospital.

Several hours later, the diver was discharged with no injuries. During the event the diver admitted that they struggled to retain items, such as gum shields, in their mouth. It is assessed that this may have led to water inhalation that led to the vomiting.
18/30During a dive to 6m, a diver experienced ear pain and the dive was aborted. Following a visit to the medical centre, the diver was cleared to dive the next day.
18/29During the concurrent deployment of four divers from a RIB (two on each side), one delayed their entry and landed upon another causing them to be stunned. Both were recovered to the boat.

After a visit to the MO, the stunned diver elected not to conduct further diving that day.
18/28The morning after conducting two dives, a diver woke with a sore ear. Following a visit to the medical centre they were advised to take 48 hrs off to allow the ear drum to recover.
18/27In UK conditions, two newly qualified Ocean Divers were conducting a consolidation diver with an instructor at a depth of 20m. One lost control of their buoyancy resulting in lost of visibility and separation.

All divers aborted the dive and returned to the surface within 60 secs of each other.
18/26The day after two dives to 6m, a trainee diver awoke to find fluid on their pillow. After visiting the MO they were informed that they had perforated their ear drum. Following three weeks of non-diving they were informed that the ear had fully healed and this was confirmed by a successful hearing test.
18/25Four days into a Sports diver course having been to a maximum depth of 20m, a diver felt numbness and pain in their shoulder. After sleeping it felt much better but they reported the issue to the supervisor.

The DDMO was contacted and the diver sent to a local chamber where he was assessed. No injuries were found and 24 hours of none diving were mandated.
18/24A diver was unable to clear their ears on descent so aborted the dive at 4m. Subsequently he was signed off diving for 2 days by the medical centre.
18/23During the first dive of an Ocean Diver cse, a diver experienced a free flow on their main regulator. On subsequent investigation it was found to be an damaged internal hose o-ring.
18/22A diver returned to the surface with a blocked ear that hadn't cleared 4 hours later. Later the diver noticed a discharge and contacted the DDMO. Following a visit to a doctor, ear barotrauma was diagnosed .
18/21During the ascent phase from a dive to a maximum depth of 18m, a diver reported feeling excessively tired. Food & drink did not improve the situation so they were taken the medical centre where low blood oxygen was diagnosed (95%). The next day levels had returned to normal but no diving was recommended for 48 hrs.
18/20In the morning a diver completed an Advanced Decompression Dive using 54% Nitrox decompression mix to 40m without incident.

Later that day the diver conducted a second decompression dive to 24 metres with a maximum planned surface to surface time of 60 mins. Once at the first decompression stop the diver realised that the computer was still planning using a 54% deco mix. This gas was not being carried and should have been turned off on the computer.

In order to fully clear decompression, the divers carried out additional stops resulting in them surfacing after 72 mins. Throughout this period they were under an SMB and both visible from the surface.
Only gases being carried should be used for planning decompression. When changing equipment configurations between dives ensure that rigorous SEEDS briefs and BAR checks are completed.
18/19During boathandling continuation training a distress call was heard on Channel 16 from a nearby small boat which was discovered to have run out of fuel. The boat was towed to a nearby harbour without further incident.
18/18During the first dive of an Ocean Diver course at 6m, a student indicated that their BCD inflator button, securing ring and button cap had come off their inflator. The instructor recovered the diver to the surface and the BCD was repaired by the SADS who is suitably qualified.

The equipment was 13 months old and had been checked prior to issue. A full BARE check had also been completed.
18/17During a dive to 23m, a diver reported discomfort in their ear and returned to the surface. Subsequent examination at the medical centre diagnosed bruised ear drums which the individual had experienced before.
18/16Following a dive to 25m, a CCR diver was unable to hold a safety stop at 6m and drifted slowly to the surface. No ascent alarms were triggered on either primary or secondary computer.
18/15During the descent on the second dive of the day, a diver reported a headache. The dive was aborted and divers recovered to the boat.

The DDMO advised that the diver was monitored but if symptoms lessened then diving could resume the following day.

18/14On the final dive of a CCR cse, it was planned to conduct a 3 minute safety stop at 6m. One student was unable to complete this and floated gently to the surface.
18/13Whilst carrying out drills on a CCR cse, a student found it difficult to breathe. A check of the diluent cylinder contents gauge revealed it to be empty.

The student bailed out to Open Circuit and aborted the dive.

The diluent contents had been checked regularly throughout the dive and there was no obvious signs of gas loss.
18/12During the swimming assessment on an Ocean Diver course, a student reported pain in their shoulder which they felt was related to a recent mountain biking injury. The DDMO was consulted and stated that the student could continue pool training but needed a medical assessment before continuing to open water.

Overnight the student was in great pain and removed themselves from the course. Subsequent medical examination revealed that a deltoid muscle had been damaged and 2 weeks rest was required.
18/11On the ascent from a trimix decompression dive to 50m, a diver received conflicting information from the two dive computers he was wearing. Although both were from the same manufacturer (Suunto), the EON Core required decompression to be conducted relatively deep (from 18m) whilst the D9tx wanted the decompression to be conducted shallower than 6m. This discrepancy resulted in the ascent time on the D9tx not reducing as quickly as the EON Core and the diver exceeding the briefed surface to surface time.

Subsequently it was identified that although both the D9tx and EON Core are modern technical computers they have different decompression algorithms which produce different ascent profiles.

When using multiple dive computers they need to have compatible algorithims
18/10During a short transit from launch site to mooring a crew member attempted to secure some loose equipment. Whilst doing so they fell overboard and the automatic life jacket inflated. The coxn recovered the crew member without incident or injury.
18/9Whilst descending, a diver felt pain in their ear at 10m. A slight ascent removed the pain and the dive resumed to a maximum depth of 16m.

After the dive the diver reported ear pain and was sent to the medical centre where they were diagnosed with a perforated ear drum. They were prevented from diving for the rest of the expedition.
18/8Whilst an expedition was conducting shake out dives in Gibraltar near JPDU, an RN patrol boat reported passing close to bubbles in the water.

A subsequent investigation by the Port Services Manager (PSM) has resulted in changes to the SOPs for AT diving expeditions. All future AT expeditions should comply with these.
18/7Ten minutes into a dive to a maximum depth of 25m, a junior diver lost control of their buoyancy and ascended from 21 to 8m over a period of 30-40 secs. After regaining control they descended back to 14m where they met their buddy and continued the dive for a further 25 mins without incident.

Approximately 90 mins after surfacing the diver complained of discomfort in their elbow. Following an examination of the affected area, the DDMO was contacted who directed that a number of checks were to be completed. Following these and a later series of checks it was decided that the issue was muscular rather than DCI. The diver was advised to take things easy and continue to drink plenty of fluids.
18/6A diver conducted two multi-level dives; one to a maximum depth of 30m for 34mins breathing Nitrox 32 and the second to 27m for 29 mins on air. Due to a navigation error the last dive required a 250m surface swim back to the shore but otherwise there were no issues with either dive and all divers reported feeling well.

Approximately 7 hrs after surfacing the diver reported that he'd had pins and needles in the palm of his hands from approximately 75 mins after surfacing. A neuro check was conducted and contact made with the DDMO who stated that a medical examination needed to occur.

This took place at a local hospital and a 5hr treatment of oxygen was given, along with fluids and an ECG. Four hours later the casualty was placed in the RCC, along with a person undergoing hyperbaric therapy, and a full treatment conducted. The diver was subsequently discharged pending further investigation

During the hospital treatment the diver revealed that they were allergic to Glyceryl trinitrate (GTN) which came as a surprise to members of the expedition who were unaware of this.
18/5At the conclusion of a 20 minute dive to 25m, most of which was spent shallower than 12m, a diver made a speedier ascent than normal from 5m. The diver had been breathing Nitrox 32 throughout the dive with air set on both dive computers as a safety factor. Neither computer showed any abnormalities for the dive.

Shortly after surfacing, the diver complained of a headache and then began to vomit. The DDMO was contacted whilst the diver was placed on oxygen and evacuated to a RCC.

After US Navy Table 5 treatment, the diver reported feeling fine and was discharged.
18/4Two divers were conducting a depth progression dive for a Dive Leader down to 40m. At 37m, one of the divers exhibited signs of discontent and erratic breathing with an indication that they wished to ascend.

The buddy assessed the diver as panicking and provided assistance during the ascent including ditching air from the BC to keep the ascent within parameters. At 10m the diver had regained control such that they were happy to conduct a 3 minute safety stop at 6m. Both divers were recovered from the water onto a boat.

The diver was visibly shaken and placed onto oxygen as a precaution whilst the DDMO was contacted. Concurrently the diver was recovered to the nearby military chamber where full neuros were completed. It was assessed that the diver had an anxiety attack that may have been brought on by narcosis.

The diver was told not to dive for 24 hrs.
Close monitoring of divers conducting depth progression is important. If a diver is in distress then a buddy needs to provide positive assistance.
18/3During a planned decompression dive to 32m, a diver was wearing two computers from the same manufacturer that used the same algorithm. Towards the end of the dive they notice that the secondary device required significantly more in water stops than the primary.

In order to clear the stops on both computers, additional gas was required and a signal was sent to the surface requesting more. This was deployed and the divers completed the higher level of stops returning to the surface without further incident.

A subsequent download of the secondary computer revealed significant anomalies on other dives that indicated that it was unserviceable.
If using multiple computers then divers should always monitor them all.

The ability to deploy additional gas to divers conducting decompression stops is very useful under certain circumstances.
18/2A group of service divers observed a civilian group in distress following a dive to 20m. They assisted with the recovery to shore and provided oxygen until the emergency services arrived. Subsequently it was learnt that the casualty made a full recovery and was grateful for the assistance that they had received.
18/1Whilst diving to 7m, a diver was unable to clear there ears. After visiting a walk in clinic, and phone consultation, with the DDMO they were prescribed medication and did not dive for 5 days.

Further details on incident reporting and the latest form can be accessed at this page.

Admin Instruction for JS Diving Safety Conference

The admin instruction for the 2018 JS Diving Safety Conference has now been emailed to everyone who registered with JSSADC.

Unfortunately a number of registration forms were not received by due to an out of date email address for JSSADC.  If you haven’t received the admin instruction then please use the contact us form so this can be rectified.

2018 Joint Service Diving Conference

The next Joint Service Diving Safety Conference will be held on 7 Mar 2018 at RAF Brize Norton and will offer the opportunity for sub aqua divers from all 3 services to meet, share experiences and knowledge.  There will be a wide range of speakers including a BSAC representative, the Superintendent of Diving, Diving Standards Officer (AT), and of course JSSADC. A key note speaker hasn’t been booked yet but we’re happy to take suggestions!

There will also be the opportunity to have a Q&A session with members of the Joint Service Sub Aqua Diving Policy Advisory Committee (JSSADPAC) and a social event in the evening.

Once again we’ve laid on courses both before and after the conference:

Full details are at the link below:

To book your place please complete the form below and send back: