News from Caversham Park Aquanauts (CPA) the friendliest scuba diving club in Reading.

David Jerram has converted to closed circuit diving with an Inspiration.

After diving with rebreather divers since 2001, including trips to Bikini Atol and a series of trimix dives each year around the south coast of the UK - the use of closed circuit rebreathers has appealed to me for a number of reasons. These include vastly extended no decompression times, longer gas duration and greater flexibility in dive planning.

However, rebreather design and technology has taken a while to get to the point where I would be happy to trust my life to any of the available units on the market.

The Inspiration rebreather has been available since the mid 90's - but has recently undergone a complete redevelopment with the inclusion of the Vision electronics system. This redesign has also included improvements in the design and construction of most of the fundamental parts that make up the breathing 'loop', electronics and controllers.

Evaluation
I tried three different rebreathers including the KISS, the Megladon and the Inspiration in late 2006 to see which unit best suited my needs.

The KISS is a simple device with a lack of electronic controllers. It simply monitors your oxygen partial pressures in the breathing loop - and provides a constant flow of O2 at depth. The diver manually injects oxygen as and when required. Being manual the unit is considerably safer to dive than any other rebreather available, though teh task loading is higher.

The Megladon is a US made variable volume mixed gas closed circuit rebreather similar to the Inspiration in many ways. The quality of manufacture is excellent, and the unit appears to be simpler than the inspiration. However, the Megladon is an expensive piece of equipment, and hard to get servicing or parts for in the UK. In addition, during my trials the unit felt very heavy and provided the hardest work of breathing rate of any of the units I tested.

The Inspiration proved to be comfortable in the water, easy to breath and featured excellent control and monitoring tools. The new inspiration has just one handset; wrist mounted which includes a full decompression computer as well as monitoring depth, time and the current partial pressure of O2. It also features simple a head-up-display to alert the diver to any inconsistencies on it's monitoring functions - providing an almost instant warning for any errors.

In addition, the Inspiration also now features a CO2 monitor, providing an essential indication of the CO2 absorbent status - helping to prevent a CO2 'breakthrough' during a dive.

Training
I completed my Module 1 rebreather training with instructor Dave Thompson and two other candidates at Sharm in Egypt. Dave is the original pioneer of the Inspiration rebreather, and his knowledge and experience were invaluable on the course.

The course was just over a week of intensive in-water and theory work - with drills and skill practice every day. We chose the Red Sea simply because we wanted to get over 11 hours on the units - and Stoney Cove really didn't appeal for that amount of in-water time during January. Surprisingly, the cost of going to Sharm for a week wasn't that much more than going to Stoney and staying in a B&B...

Having qualified, I am now embarking on a 12-month practice regime. My aim is to stay shallower than 40m and to avoid decompression until I have really built up the hours on the unit.

Diving with a rebreather diver
Buddying up with me is not that dissimilar to diving with a conventional open circuit partner. I will usually carry a seven-litre stage bottle for bailout as a safety backup. This is yours in the event that you run out of air.

There is a set of pre-dive checks that I have to perform before getting into the water. These are my equivalent to a buddy check, and I will never miss this out.

My buddy and I will normally carry out a 'bubble check' at around 6m before descending. Naturally ther should be very few if any bubbles coming from me - and lots coming from you...

In addition, there are some pretty simple things to do in the event of a problem underwater. I can manage most of these myself - but a regular dive partner on open circuit may want to learn more about them. If you want to dive with me this year let me know and I can run through the skills and drills with you before hand.

Club Diving
I will be using my rebreather for all diving in 2007 and for the foreseeable future. All simple dives will be treated as training by me - so please forgive me if I seem to be 'prating about' a lot when on the boat or underwater. My mind will be on other things a lot this year.
I will continue to organise and support club diving this season, but will probably not be teaching in the pool or open water as it would be wrong to do so while using this equipment.

Open Evening
There will be an open evening to chat about buddying up with a rebreather diver on February 20th 2007 at the club.