Organised in conjunction with DAN Europe and PADI, Rebreather Forum 4 is an event like no other. It’s not generally open to the diving public – diving professionals need only apply – and previous Forums have occurred only once every ten years or so (although plans are afoot to increase the frequency of future events).

The format of the event would be largely unfamiliar to most divers too – after three days of presentations on a diverse range of rebreather-related topics delivered by leading academics and thought-leaders from across the globe, attendees were invited to discuss and debate a series of ‘consensus’ statements. Formed from key findings taken from the presentations by a panel of academics, these statements are designed to guide the industry forward with a view to making rebreather diving safer for us all.

Whilst the presentations held at the University of Malta’s Valletta Campus formed the core of the event, there were plenty of other rebreather-related activities to keep those in attendance occupied. Often described as the ‘Chuuk Lagoon of the Mediterranean’, no visit to Malta would be complete without diving some of its world-famous wrecks. For the weeks either side of the main symposium, Malta’s many dive boats were filled with more rebreathers than the island had ever seen! In conjunction with Heritage Malta, attendees dived some of Malta’s best-loved deep wrecks – Le Polynesian, HMS Southwold, Schnellboot S-31 and more.

Bail out rebreathers are a hot topic amongst diving explorers and Andy Pitkin’s presentation on their use in long-range cave exploration generated much discussion. With their adoption on the rise, his talk highlighted the need to develop and document practices covering their safe use. Mouthpiece retaining straps caused much discussion too with heated debate on the pros and cons of their use. Whilst a clear consensus wasn’t reached, those in attendance recognised their use as a strategy for avoiding loss of the mouthpiece and minimisation of water aspiration in the event of loss of consciousness underwater.

Advances in CO2 monitoring and the design of rebreather scrubbers came under the spotlight with presentations from popular diving physician Professor Simon Mitchell and Dr John R Clarke – one of the foremost experts in scrubber technology and science. Clarke’s presentation focused on factors affecting scrubber efficacy including unexpected variations in grain size, cold water and the diver’s own CO2 production rate. Mitchell, on the other hand, highlighted developments in CO2 monitoring and the mechanics of CO2 exchange in the body. Mitchell’s thought-provoking talk highlighted the need for the development of capnography and accurate end-tidal CO2 monitoring within rebreathers.

Decompression guru Dr David Doolette gave a much-anticipated update on advances in decompression modelling. Doolette focused on four key areas of research – biomonitoring venous gas emboli (VGE) and heart rate variability (HRV) in decompression planning, inner ear decompression sickness (IEDCS ) and alternative decompression planning strategies for deep technical dives. Although still in its infancy, Doolette’s research offered a promising glimpse at future decompression modelling.

Talking of exciting new technologies, DAN Europe founder Professor Alessandro Marroni delivered a fascinating preview of the DAN AVATAR Project – a real-time diver-monitoring system that uses wearable underwater biometric sensors, an ultrasound device that transmits sensor readings to the surface and technology to forwards this data from remote diving locations to DAN’s team of scientists.

Designed to monitor expedition divers operating in remote locations, the system promises to monitor health and decompression risk underwater and provide guidance should they run into problems. It’s exciting technology that could revolutionise diving safety.

For many, the highlight of Rebreather Forum 4 came on the final evening when all in attendance gathered for a celebratory banquet at the Xara Lodge in Rabat. After a short introduction from GUE President Jarrod Jablonski, Dr Richard ‘Harry’ Harris took to the stage to deliver the event’s keynote address. Best known as the Australian anaesthetist and cave explorer who played a crucial role in the Tham Luang cave rescue in Thailand back in 2018, Harris and the Wetmules team attempted a 230-metre deep cave dive at the Pearse Resurgence in New Zealand using hydrogen as a diluent gas – something that has never been done before.