Diving with a Dolphin
by John Ralston
Ever since I tried one in the pool a few months ago I really fancied doing the BSAC Draeger Dolphin course. The Dolphin is simple (for a re-breather), robust and comes from a manufacturer – Draeger – who has been around longer than I have!
As many of you will know a rebreather is quite a different kind of scuba kit. Most people dive ‘opencircuit’ which means that you breathe in from your cylinder and out straight into the surrounding water. Plenty of oxygen-rich bubbles. A re-breather takes your waste air and re-circulates it by scrubbing out the unwanted carbon dioxide and topping up the oxygen. No bubbles, no waste.
I was having problems scheduling the required training course so when I finally managed to pin down some dates, it was the week after our Egypt trip... in the UK... in November... hence my quip about ‘diving with a different kind of dolphin’ was suddenly less amusing than when I had made it!
the course begins
I arrived at ‘8 Acre Lake’ a few miles from Hull on a very cold but sunny Tuesday morning. It was 10am and the frost was still there from the day before. Bear in mind that five days earlier I had been diving the reefs and wrecks of the Red Sea in 25 degree water. I was assured that the water temperature would be 7 degrees, but this seemed like too big a difference to compute!
Day 1
This was mainly theory and an introduction to the units – learning the basic setup. We were also scheduled to do our first dive. I don’t mind admitting I was very apprehensive at this point, probably more so than my first open water dive. Maybe this was because I had not spent every Thursday for the last eight weeks practising in the pool. But after a few minutes virtually all my anxiety was gone and I was starting to enjoy this re-breathing lark.
We started with a gentle progression of exercises which included re-learning how to remove diving with a dolphin and retrieve the mouthpiece (hint – it floats above your head!), breathing from an alternative air source (AAS) and some mask clearing – it was just like being a novice again.
The only real problem I had was buoyancy – you don’t realise how much you control small movements purely by breathing in to ascend and out to descend. With a re-breather, the volume of air is pretty constant because when you breathe out, the air from your lungs fills the ‘counter-lung’. So your volume doesn’t change and neither does your buoyancy. I had become what I detested – a dreaded bottom feeder, saying ‘hello’ to a really silty lake bed a number of times. Being worried about positive buoyancy seems to have the opposite effect. We also had drilled into us the two insuperable rules: pre-dive ‘Gas, Gauge, Gag’, plus the immortal lines ‘If in doubt – bailout.’
Day 2 dawned
Well it didn’t really dawn – it crept in under cover of freezing fog. More theory covered a range of subjects. Including care and maintenance, checklists and more checklists (there seem to be loads). We also got in two more dives with well over 100 mins in the water, where we drilled AAS ascents, mouthpiece removal and retrieval plus AV/Tows to shallow water including a de-kit of the casualty.
Day 3
We covered more of the gas theory (reasonably easy for anyone who has done the Advanced Nitrox course)and more AAS ascents and controlled buoyant lifts. Due to the cold we had not spent as much time in water as we would have liked, so we were definitely going to do an extra day.
Day 4
I wasn’t feeling well. We had a dive, followed by some mopping up of the theory and finally the exam. I cut short my dive, as I felt pretty ikky, but I recovered for the rest of the theory and the exam. Not a multi-choice question in sight – fifty written answers were required. OK some only required a value or a figure but others needed a longer answer/explanation and yes,
I passed!
Did I enjoy it?
Yes! But will I get one? Errrr might do... but it might not be for everyone.
A unit like the ‘Dolphin’ is certainly no black magic box of tricks. It may require a bit more care and attention putting it together prior to diving, and it won’t replace open circuit. But if it suits the sort of diving you want to do and you want to extend your horizons by learning something new, then I can highly recommend the course.
8 Acre Lake
‘8 Acre Lake’ is a dive location that beats any other for hospitality. The owner could not have been more helpful and limits numbers to thirty divers so it never gets too busy. The viz is apparently a lot better in the summer than the 2 – 3m we had. They have also sunk a few attractions for divers; a light airplane, a couple of yachts and a selection of fibreglass farmyard animals at depths of up to 14m.
A big thanks to my instructor, Dennis Wigg dennis.wigg@bsac.com from Robin Hood Watersports, who did an excellent job and also to Jeff Reed jeff.reed@bsac.com who lent me cylinders for the course and answered my many emails beforehand.
Now time to make a start on next year’s Christmas list.
NEWS UPDATE
John is now the proud owner of a shiny new Drager Dolphin and is loooking forward to a summer of making the maximum use of it.
For more information on the courses or to enquire about becoming an instructor or instructor trainer please contact the BSAC Technical Chief Instructor
Ever since I tried one in the pool a few months ago I really fancied doing the BSAC Draeger Dolphin course. The Dolphin is simple (for a re-breather), robust and comes from a manufacturer – Draeger – who has been around longer than I have!
As many of you will know a rebreather is quite a different kind of scuba kit. Most people dive ‘opencircuit’ which means that you breathe in from your cylinder and out straight into the surrounding water. Plenty of oxygen-rich bubbles. A re-breather takes your waste air and re-circulates it by scrubbing out the unwanted carbon dioxide and topping up the oxygen. No bubbles, no waste.
I was having problems scheduling the required training course so when I finally managed to pin down some dates, it was the week after our Egypt trip... in the UK... in November... hence my quip about ‘diving with a different kind of dolphin’ was suddenly less amusing than when I had made it!
the course begins
I arrived at ‘8 Acre Lake’ a few miles from Hull on a very cold but sunny Tuesday morning. It was 10am and the frost was still there from the day before. Bear in mind that five days earlier I had been diving the reefs and wrecks of the Red Sea in 25 degree water. I was assured that the water temperature would be 7 degrees, but this seemed like too big a difference to compute!
Day 1
This was mainly theory and an introduction to the units – learning the basic setup. We were also scheduled to do our first dive. I don’t mind admitting I was very apprehensive at this point, probably more so than my first open water dive. Maybe this was because I had not spent every Thursday for the last eight weeks practising in the pool. But after a few minutes virtually all my anxiety was gone and I was starting to enjoy this re-breathing lark.
We started with a gentle progression of exercises which included re-learning how to remove diving with a dolphin and retrieve the mouthpiece (hint – it floats above your head!), breathing from an alternative air source (AAS) and some mask clearing – it was just like being a novice again.
The only real problem I had was buoyancy – you don’t realise how much you control small movements purely by breathing in to ascend and out to descend. With a re-breather, the volume of air is pretty constant because when you breathe out, the air from your lungs fills the ‘counter-lung’. So your volume doesn’t change and neither does your buoyancy. I had become what I detested – a dreaded bottom feeder, saying ‘hello’ to a really silty lake bed a number of times. Being worried about positive buoyancy seems to have the opposite effect. We also had drilled into us the two insuperable rules: pre-dive ‘Gas, Gauge, Gag’, plus the immortal lines ‘If in doubt – bailout.’
Day 2 dawned
Well it didn’t really dawn – it crept in under cover of freezing fog. More theory covered a range of subjects. Including care and maintenance, checklists and more checklists (there seem to be loads). We also got in two more dives with well over 100 mins in the water, where we drilled AAS ascents, mouthpiece removal and retrieval plus AV/Tows to shallow water including a de-kit of the casualty.
Day 3
We covered more of the gas theory (reasonably easy for anyone who has done the Advanced Nitrox course)and more AAS ascents and controlled buoyant lifts. Due to the cold we had not spent as much time in water as we would have liked, so we were definitely going to do an extra day.
Day 4
I wasn’t feeling well. We had a dive, followed by some mopping up of the theory and finally the exam. I cut short my dive, as I felt pretty ikky, but I recovered for the rest of the theory and the exam. Not a multi-choice question in sight – fifty written answers were required. OK some only required a value or a figure but others needed a longer answer/explanation and yes,
I passed!
Kitted up and ready to go (L–R): John with Dennis Wigg and Tony Cumper
Did I enjoy it?
Yes! But will I get one? Errrr might do... but it might not be for everyone.
A unit like the ‘Dolphin’ is certainly no black magic box of tricks. It may require a bit more care and attention putting it together prior to diving, and it won’t replace open circuit. But if it suits the sort of diving you want to do and you want to extend your horizons by learning something new, then I can highly recommend the course.
8 Acre Lake
‘8 Acre Lake’ is a dive location that beats any other for hospitality. The owner could not have been more helpful and limits numbers to thirty divers so it never gets too busy. The viz is apparently a lot better in the summer than the 2 – 3m we had. They have also sunk a few attractions for divers; a light airplane, a couple of yachts and a selection of fibreglass farmyard animals at depths of up to 14m.
A big thanks to my instructor, Dennis Wigg dennis.wigg@bsac.com from Robin Hood Watersports, who did an excellent job and also to Jeff Reed jeff.reed@bsac.com who lent me cylinders for the course and answered my many emails beforehand.
Now time to make a start on next year’s Christmas list.
NEWS UPDATE
John is now the proud owner of a shiny new Drager Dolphin and is loooking forward to a summer of making the maximum use of it.
For more information on the courses or to enquire about becoming an instructor or instructor trainer please contact the BSAC Technical Chief Instructor
Page last modified: 16th Aug 2006 - 15:34:42