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REGULATOR Aqua-Lung Mistral
Older readers will remember twin-hose regulators. They had a single-stage valve that was at the A-clamp. You breathed through the twin corrugated hoses, which had simple valves that allowed the air to pass only one way.
     They were hard to breathe from and impossible to share. If you took a twin-hose regulator out of your mouth, you had to be sure to tilt it well to one side when you put it back, or your next inhalation was akin to drowning.
     If you got the mouthpiece much higher than the valve, it free-flowed. If you somehow got the mouthpiece lower than the valve, it became like sucking on an empty bottle.
     The invention of the now commonly used single-hose, two-stage regulator made diving possible for everyone, not only the superhuman, but Aqua-Lung has decided to revive the twin-hose regulator in the form of its new Mistral.
     This is also the name used by Cousteau and Gagnan for their original valve, and the French Navy was using Spiro Mistrals until only recently.
     In mid-February,after waiting while it had been tested by another British diving magazine, I was sent what I was told was the only example the importer had available. For purposes of hygiene, I was ready to take the hoses apart and give them a good spray with some disinfectant, but when it arrived it appeared that the Mistral had never even been wet.
     In fact it was still very shiny and, indeed, quite sexy, with its seductive mixture of chromed brass and black rubbery hoses. I found myself wanting to own one before I had even tried it.
     So thats why the company has revived the twin-hose idea in the form of the new Mistral - because it knows people will want to buy it. In the commercial world, thats reason enough.
     I wanted to see how easy it would be to clean the hoses and found that although they readily unscrewed from the mouthpiece, they did not do so from both ends. So it would be quite difficult to dislodge remaining water, after spraying and rinsing.
     I was careful to put the mouthpiece back round the right way, so that the inhaled air went to the exhaust port.
     What is the advantage of a twin-hose regulator Some would say it makes you look like a proper diver, of the likes of Cousteau, Hans Hass and Commander Crabbe.
     Others suggest that because the bubbles are exhaled from behind your head, they wont frighten the marine life. Somehow, they think a twin-hose gives you a Harry Potter Cloak of Invisibility.
     I have had considerable experience photographing skittish scalloped hammerhead sharks, using both closed-circuit rebreathers and open-circuit scuba. With a CCR, though you may release no bubbles at all, you are still not invisible. The only way you can fool the hammerheads into not seeing you is to make like a rock.
     Whether bubbles come out of the regulator in your mouth or from the back of your head, or out of your backside for that matter, one emission and the sharks are off!
     If you are a photographer and irritated by exhaled bubbles coming up around your face,I suggest you get a regulator with a longer exhaust T, or find some way of extending the one you have. But I still want a Mistral. Why Because it looks cool, thats why!
     Of course it would be really stupid to swap a modern regulator for something that was going to be asthmatic to breathe from. Aqua-Lung has thought of that.
     The new Mistral is now a two-stage regulator. The maker has positioned the second stage with its exhaust port alongside the first stage at the back of the divers head, and fitted to it two corrugated hoses and a mouthpiece. In fact it still has the single mp hose between the two stages. This runs in a short loop between them.
     The version tested and certified for EN250 and all the other Euro standards was fitted with a long loop of hose, and it is suggested that you use this instead of the short one also supplied, if you intend to use it in cold fresh water.
     I bet this is for legal reasons, but we can pretend that the longer length of mp hose allows a greater heat-sink for the depressurised air, conveniently ignoring the fact that it is covered in a thick layer of insulating rubber. The longer hose does make a lovely loop, which calls out to get hooked on something as you pass by. I took care to reroute it in a loop to a first-stage port at the opposite side to its connection to the second stage, so that it presented slightly less of a hazard.
     The Mistrals first stage is virtually the same as that of the Aqua-Lung Titan. It has the usual four mp ports, the first of which is for the second-stage feed of the Mistral while the rest are meant to be available for a conventional second stage on a hose, to use as an octopus for a direct-feed for a BC and for a direct-feed for a drysuit.
     I say meant to be, because I was unable to connect the fourth mp hose. There was too little space between it and the fixed plastic second stage, and that was after an hour of trying different combinations. There is only one high-pressure port. So I used the Mistral on a twin-set alongside a conventional Titan single-hose regulator.
     The omission of the second hp port could also be its Achilles heel when it comes to sales. The diver who buys this expensive and, some would say, capricious item will buy it simply because he wants it. He really wants it.
     The same person has probably bought a gas-integrated computer too, perhaps for the same reason. This means he will fit his transmitter and have nowhere for a secondary hp hose and contents gauge unless, like me, he uses it as part of a manifolded twin-tank configuration.
     In the water, with the second stage so far from my mouth, it was obvious that breathing was going to take more effort than with the equivalent Titan, but I was surprised to find it less arduous than I had expected.
     Compared to the breathe from the conventional Titan LX Supreme, the air supplied is much more diffused. Thats because it has not been squirted directly from a valve into your mouth but has to make its way first along a convoluted hose. Unlike the mouthpiece of a rebreather, there was no ability to close this one if I took it out of my mouth while submerged.
     Flooding a hose meant tilting my head and body well to the left, so that the water was expelled down the left hose and out of the exhaust with the next exhalation. This again proved less difficult than expected.
     True, there were no bubbles coming up near my face, but there is a price to pay for this small luxury. Besides the increased work of breathing and the circumspection needed before replacing a flooded mouthpiece, the hoses tend to float. I felt they needed weights, such as those the Inspiration and Prism CCR have.
     I also needed to fit the mouthpiece at the right rotation to the hoses, or discomfort ensued, despite the Comfobite mouthpiece. After half an hour under water, the mouthpiece started to rub uncomfortably on my upper front gums and, yes, the performance altered depending on whether I was looking up or had my head down. In that respect, it was just like Gagnans original Mistral.
     The other mistake I made was to chuck the hose out of the way over my head when I finally surfaced. This caused it to go into dramatic free-flow and the buoyancy provided by all that rushing air made it impossible to retrieve until I was completely clear of the water.
     This did not dampen my enthusiasm, only my tonsils.I very quickly became accustomed to the slight quirkiness of the Mistral and can confirm that it is still a very desirable piece of kit. Its like having a Mont Blanc pen or a Rolex Submariner - theres no real reason for it but it looks great.
     In the ice-cold waters of Sweden, the mouthpiece kept my lips comfortable, and the inhaled air felt less frigid than it might have done. It shouldnt present any problems with freezing, because the first stage is so designed that moving parts do not come into contact with the water.
     The problem is that Ive been spoiled by using rebreathers.I couldnt really focus on any positive advantage of owning the Mistral when I was under water, other than the looks I would get strolling along Swanage Pier on a hot summer weekend, or at fancy dress parties.
     Rest assured, however, well see a lot of divers in the movies using them. Film directors will love how the Mistral looks, and so do I.
The Aqua-Lung Mistral costs £460.
  • Aqua-Lung UK, 0116 2124200, www.aqualung.co.uk


  • Divernet Divernet
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    + A sexy-looking bit of kit


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    - Harder to use than a conventional single-hose regulator
    - The price