Paul Haynes

Haynes Marine Ltd. (www.haynesmarine.com) was recently contracted by a manufacturer of submersible Rigid Hull Inflatable Boats (RHIBs) used by Special Operations Forces (SOF), to manage manned submersible customer acceptance diving operations in accordance with UK Diving at Work Regulations (DWR).  To comply with DWR required a means of providing diver to surface and surface to diver communications.  The use of un-tethered manned submersible vehicles precluded the employment of hardwire communication systems and due to training restrictions, Diver Through Water Communication (DTWC) systems were discounted.  As a consequence, following a desk top product review, the Underwater Digital Interface (UDI) system was selected.   Despite initial reservations about UDI capability, the system exceeded all expectations and quickly became a key aspect of diving safety throughout the project and an important aid to submersible craft underwater navigation.  The effective use of UDI required minimum self training and set up time.  Communication was consistent, reliable and quickly transmitted between the surface Diving Supervisor and the diver and vice versa.  Extended duration dives of up to 130 minutes were undertaken in 5°C off the Scottish West coast during winter.  Water types ranged from salt to fresh water and in areas a mixture of both. Such conditions are challenging to any acoustic technology and battery duration, however the UDI performance was faultless and the system will now form an integral aspect of my future dive management strategy.  


In an effort to further explore UDI’s potential, during a recent Closed Circuit Rebreather (CCR) training course, once CCR skills had been demonstrated and replicated by the student to an appropriate standard, for the next phase of training, simple messages describing CCR failure modes were programmed into the UDI, which were worn by both myself and the student.  Example messages included: High PO2, Low PO2, O2 valve fail closed, O2 fail open, loop flood, breathing distress and anxiety, sudden loop increase, catastrophic gas loss.  At appropriate moments during the training dives, one or a series of CCR failure messages were remotely transmitted to the student who then reacted in accordance with previously taught procedures.  Again UDI exceeded expectations, the ability to discretely transmit one or more failure mode scenarios to the student at impromptu times without having to stop and pre-warn the student, significantly enhanced the student’s training and learning experience by the presentation of sudden, unexpected “real world” failure scenarios.  In addition, using UDI, decompression obligations were readily monitored and the digital compass proved to be useful navigation aid on less well know dive sites.


I highly recommend the UDI system to any diving organisation who wishes to enhance their dive management safety and to diving instructors who wish to expand their training capabilities and optimise their students training experience.



Paul Haynes

Managing Director Haynes Marine Ltd

Specialist diving consultant

Former Special Forces Diving Instructor

Advanced Mixed Gas CCR Instructor Trainer