Blog Archives

New JSSADC Email Addresses

After our conversion to MoD Net, all JSSADC email addresses have changed.  You can now contact us using the following:

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.

18/26The 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.