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JohnJohn Bantin has been a full-time professional diving writer and underwater photographer since 1990. He makes around 300 dives each year testing diving equipment.

BC AQUA LUNG PRO QDI3

FOR PEOPLE INVOLVED IN AN ADVENTUROUS ACTIVITY, divers are a pretty unadventurous lot. When someone invented the direct-feed to the ABLJ, the forerunner of the BC, we accepted it - provided we could still have that little separate cylinder of air decanted off our main tank, just in case we needed inflation.
Before that the ABLJ, a development of the simple life-vest, was inflated by mouth. You used a flexible tube, also for dumping on ascent. Thats where the idea for todays corrugated hose came from.
Few divers now cling to the auxiliary cylinder, but everybody seems to stick with the corrugated hose.
Divers are still taught to dump air by raising the hose and releasing it from the oral inflation valve. It works, but also lets water back in the other way, though that isnt too important if you can bear its weight once out of the water.
If the first drysuits had been supplied with oral inflation via a corrugated hose, they would still have corrugated hoses too. But divers manage to let air into their suits on the way down and the expanding air out on the way up without too much trouble.
So why do modern BCs all seem to have corrugated hoses Because its very hard to sell the idea of going without when every new diver has been taught how important it is to lift and dump on the way up.
Almost every BC comes with a dump-valve. Even rebreather counter-lungs have them. From time to time, every BC manufacturer has offered a model that uses a modern direct-feed system like that of a drysuit without the corrugated hose. The Pro QDi3 option is the latest such offering from Aqua Lung/Seaquest.

Comfort
This BC is loaded to the gunwales with extras, but I found it quite slim-fitting and with an unrestricting profile when swimming horizontally. Plenty of adjustment was available at the waist, and this was depth-compensating (stretchy).
The shoulder buckles swivel so that the straps automatically take the easiest route. There was no feeling that I was yomping with a full pack while standing fully kitted at the surface. I did need occasional help sorting out twisted straps, and this would be more evident when wearing a drysuit.
I liked the way Aqua Lung provides a visible stowage device for a right-rigged octopus. I found that I could even stow my left-rigged long-hose octopus in it - dont ask me how!
The single tank with which I used this BC sat in the back-pack with no danger of it slipping out.

Efficacy
This standard jacket-style BC includes just about every extra the designers could think to offer. The integrated-weight system holds up to 9kg securely in its pouches (size ML), yet the buckles are easily released on demand.
It is supplemented by trim-weight pockets hidden away so well that some owners will never notice them. These will take up to 2kg or so each, depending on BC size.
Pockets are a little shallow, not surprising considering the space taken up by the integrated weights and mechanics of the i3 system. The pockets concertina outwards. The zips worked the right way, so they could easily be located by feel and were no problem to use.
The i3 control falls easily to hand and inflation is quick yet progressive. It was no imposition
to use, and it was nice not to have that hose floating around, although nowadays I always tuck a corrugated hose through a sternum strap anyway, and inflate as I would a BC such
as the Pro QD i3.
The i3 system makes it even simpler. Pull up the lever to inflate and push it down to deflate.
Im not sure about the Aqua Lung copywriters suggestion that you should pull up to go up and push down to go down, however - I tend to dump on the way up!
After an initial few attempts pressing the lever the wrong way, I soon got it right.

Control of Ascent
The i3 system worked like magic, all achieved by internal cables. There is a second low-profile valve at the lower back, for those who can do bum-up horizontal ascents and for people like me who like to bomb down headfirst from the surface, camera at the ready.
Whichever angle I was at, the automatic system operated by the lever seemed to let the air out from wherever it was required.
For those who dont believe in magic, the individual dump valves also worked well when operated by their pull-cords.
The buoyancy cell is very slim at the top, so there was no danger that some of the air might be lodged in the other side, causing me to squirm to get that last bit out.
I always had total control of my ascent, without needing a second thought.
This valve also has a low profile that avoids it snagging on things, and virtually eliminates water coming back in the other way, which makes the BC as light when you leave the water as when you get in.

Surface support
This is not a BC that inflates to the size of a small dinghy. Maximum available lift is quite modest, even though the buoyancy cell incorporates a gusset that allows it to expand outwards.
However, I have always believed that you need no more lift in a BC than you have weight on your belt, or integrated-weight system.
Waiting to be picked up at the surface, I didnt enjoy armchair support, and the odd wave did break over my head. Luckily I dont have a problem with getting wet.
What was important was that all the lift available was in the right place. The inflated part of the buoyancy cell was under the water, providing displacement rather than billowing in the wind over my head.
For those of us who habitually use the last of our air getting pictures (slapped wrist) the long oral inflator hose is retained in a pocket at the left epaulet and is easy to deploy and use.
It can easily be removed to provide an access port should you ever need to rinse out your BC.

Ease of removal
When handing up my weights, their pouches pulled out from where they were stowed
quite efficiently.
Shoulder buckles fastened with unique Aqua Lung flat clips meant learning a new trick, but
I was easily able to swim out of the rig as it floated at the surface. That was with an aluminium tank. Im not sure it would have been so simple weighed down with a heavy steel tank, once the buoyancy of my own suited body had been removed from the equation.


Divernet
i3
i3 buoyancy controller.
Low-profile
Low-profile dump valve.
Integrated
Integrated weights and octo pocket.

SPECS
AQUA LUNG PRO QDI3
PRICE 400
STYLE Conventional jacket BC
DRY WEIGHT 3.8kg
POCKETS Two (zipped)
INTEGRATED WEIGHTS Yes, with trim-weights
D-RINGS 6
MAX LIFT IN SIZE M 16kg
SIZES XS to XXL
CONTACT Aqua Lung, www.aqualung.com
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