June 1998
Hot pants!
John Bantin tries a new undersuit that comes with heating elements to keep the shivers at bay.
Aquion XCM heated undersuit (£990).
WHEN we dive we try to insulate ourselves from the effects of cold water by wearing thick undersuits, but no one can say that thick clothing underwater is comfortable. We all like the unrestricted feeling of diving with a thin wetsuit when we can, so the folks at Aquion - the maker of those deservedly popular drysuits - have come up with a thin undersuit that allows you to stay warm simply by turning up the heat!
The Aquion XCM (Extreme Climate Management) heated undersuit has five strategically placed carbon conductive heating elements, one at each calf and forearm, and a large one at the small of the back.
They are powered by a substantial powerpack that can be rigged to your tank in the manner of a pony bottle - I used Buddy Pony Bottle Bands - or any other way that works. Its weight substitutes for lead.
However, it is not just a case of jumping in with some hot elements. The whole thing is rigged to a computer control-box installed in the breast pocket of the suit. Each pad has its own power control and temperature-monitoring circuit, and two sensors - one for the power supply and one as a safety monitor. The computerised control and power management system has two independent processors which continuously check each other.
I decided to try the suit one February morning at Stoney Cove, when the blue faces of those returning from their forays told me that the water was adequately chilled. The suit appeared to be an ordinary if modern design, with a showerproof outer layer and an inner fabric made of a high TOG value. This was quilted to a wicking material designed to transmit moisture caused by sweat away from the wearer's skin.
What made the undersuit unusual was that it had a few stiff inserts (the heated pads), and a cable that needed connecting to a similar one inside the drysuit.
I was connected up by Paul Scevington, Aquion's electronics whizz-kid, via the control module to his lap-top PC, which uses Windows 95. By this means we were able to preselect temperatures for the variously positioned pads.
I chose arbitrary temperatures in the range of 36-38*C. Obviously experience will tell you what is best for your taste, but it is not possible to select temperatures higher than a skin-toasting 46*C.
Once I had donned the drysuit, I was able to mount the aqualung complete with its battery pack on my back in the normal way. I had only to connect the direct-feed hose to the inflation valve, and the power lead from the battery to the umbilical of a similar-looking tap-switch, and I was ready to dive.
Two taps switched on; the system did a diagnostic check and I felt things hotting up. This took about 40 seconds. The first thing I noticed in the water was that I was hopelessly over-weighted. This was due to the loss of buoyancy normally afforded by a thick undersuit, combined with the additional weight of the battery.
With this adjusted for, I was soon swimming about as happy as Larry, except that I could only feel my forearms getting comfortably hot. Alas, my buddy was without the luxury of this high-tech heating system, so we were still limited by her ability to withstand the wintry water. We had to return to shore within 15 minutes.
New arrangements having been made for a stand-by diver, I was soon back in the water, but not before Paul had tweaked things again with his PC.
This time I noticed no pronounced heating effect, and after a short time finning around in an unusually easy way because of the unconstricting nature of the thin undersuit, I decided that perhaps we had forgotten to switch the XCM heating system on.
I tapped the on/off switch twice as prescribed and lay down on the bottom next to the sunken aeroplane to wait for things to warm up. Instead I got very cold indeed. I had turned it off!
Later Paul pointed out that the idea of this XCM system is not to leave heat blisters on various parts of the diver's anatomy but to keep him from getting cold! Turning the system back on gave me a dramatic demonstration of its effectiveness and I was soon comfortable again.
My only criticism is a small one. I was so comfortable in the drysuit that I really started to notice how cold my hands were getting. Normally I would have expected these to have become numb appendages but in this case they just felt very cold. The Aquion XCM had simply spoiled my ability to be a proper coldwater diver!
The whole thing is run from a lead- acid battery similar to one supplied with the Custom Divers 12V technical diving light. It takes 6-8 hours to charge and the burntime varies between a couple of hours and many, depending on how warm the diver wants to be and how cold the water is.
The XCM system costs £990.
Aquion, 01709 780980.
Hairy moments re-lived on screen
A PC interface allows divers to analyse on dry land dives logged on a Spyder Advanced Computer watch.
Suunto PC interface and dive analysis software (£100).
IT was Groucho Marx who once said: "A seven-year-old child could do this - get me a seven-year-old child!" When it comes to modern computer technology, I tend to think along the same lines.
However, as I am being dragged kicking and screaming into the 21st Century, I reluctantly took up the challenge when Suunto sent me a PC interface and software for the Spyder Advanced Computer Watch.
It was not too difficult to make sense of. I took the precaution of following the instructions, installed the software (Windows 3.11 or Windows 95) from the two discs supplied, and slotted the Spyder into its interfacing connection. Very soon it had downloaded all the information and I was able to examine details of the 40 or so dives I had logged on the Spyder since I clamped it on my wrist.
I was amazed to see that many of my dives followed a profile that would be approved of by even our most dogmatic readers.
However, it was more interesting to have a close look at those that, through no fault of my own, had involved a less-than-textbook execution. By using the cursor you can pick and examine any moment in the time/depth graph, and the PC also graphically displays the model tissue-saturation percentages.
I was especially interested in one dive in Palau where my friendly dive-guide decided to take me through the Blue Hole (15m deep) and then on a long and exhausting 30min swim at depths between 10m and 20m to Blue Corner, where we descended below 30m. This is where I decided I'd had enough, mainly because I was running low on air.
Another dive at Gordon Rock in the Galapagos had been subject to a strong downcurrent in the 10-18m range, just at a time when I would have preferred a gentle and controlled ascent with lots of sensibly controlled decompression stops. I ended up having to swim hard with my BC fully inflated to gain the surface.
In both cases I was able to examine the nitrogen loading of the nine tissue models at any point during my progress. It was gratifying to see that at no time did I ever come close to 100 per cent, despite the suspect dive profiles.
It was also interesting to reconfirm that no fast-ascent warning was ever displayed, and to see that the water temperature in the Galapagos during an El Nino year was exactly the same as in Palau - on the other side of the Pacific - two weeks before.
Like many other computer/PC interfaces, this one allows you to type in details of the dive not recorded by the Spyder, including air in and air out, used to compute your average air consumption. You can either keep all the information acquired in electronic form or print out hard copies for your logbook.
The PC Interface and software for the Suunto Spyder ACW costs £100.
Blandford Sub Aqua, 01923 801572.
Gas proofers need to keep wrist watch
No, Santa's elves haven't taken up diving: it's just John Bantin demonstrating the front-entry zip of the Sea Lion drysuit. He found the suit nice, but deficient in the wrist-seal department.
Sea Lion drysuit (£542).
WHAT is going on in the Far East? Have all the plantation workers gone off to sell their unit-trusts and panic at the doors of their banks, leaving a shortfall in rubber production? Are drysuit manufacturers having to cut back on drysuit seals?
The last drysuit I tried had inadequate wrist seals, with no hope of staying watertight if I attempted to grip anything with my hands.
Most drysuit manufacturers tend to get their supplies from only a couple of different manufacturers, and this "short seal syndrome" is beginning to become something of a problem.
In January I went to Stoney Cove to try a Sea Lion suit from a newcomer to the diving market, Respirex. This is the company that makes the suits you see worn by firemen at chemical spillages in Slough, and which has been in business making gas-proof and biological warfare suits for industrial and military applications for a long time.
I am sure there is not much its people don't know about the business.
However, diving is bit different. Leisure divers do it under water, and they do it because it's fun - or at least it should be.
I noted Stoney Cove's less than welcoming January water. It was so cold that the ducks were wearing anoraks. I examined the wrist seals of the Sea Lion suit. They were so short that even on a surface swim they failed to keep the water out.
There was no way I was going to take the long ride back down the motorway with arms resembling something fresh from the meat-packer's cold-store. Instead I opted to use my trusted Gates suit which, like the DUI suit of my buddy, had latex wrist seals that made at least 8cm of close contact with my wrist.
The Sea Lion suit does not have a revolutionary design but, wrist seals apart, it seems to be made to a high standard with a lightweight rubberised cloth.
All the seams are glued and securely taped on the inside. It appears to be made from eight panels with an elasticated panel let into the back to gather the material and give it a slightly fitted look. It is a nice suit.
There is a diagonal front-entry zip hidden by a velcro flap. There is provision for braces, but none were supplied. These would have helped to take up some of the excess material needed to pull the suit up over the head, and allowed a tuck to be formed at the waist.
The boots are standard- looking items that need to be combined with a thick pair of socks or thinsulate foot mitts.
A chest-mounted Apeks valve and an automatic shoulder dump completes this drysuit. I did find the diagonal zip a little uncomfortable - a bit like having a garden cane stuffed up your jumper.
Respirex tells me that the company is looking at the wrist-seal problem and will probably source them elsewhere in future.
Please, if you are a drysuit manufacturer about to send me a product to test, be sure that the wrist seals are long enough to perform the function for which they were designed. It saves disappointment later.
The Sea Lion drysuit as tested costs £542.
Respirex, 01737 778600.
A likeable lantern
A view of the Ikelite RCD lantern. We liked its protective front shroud, its switch and its battery compartment closure.
Ikelite RCD diver's lantern (£51), RCD rechargeable (£130).
THE Ikelite RCD is a diver's lantern with an 8cm-diameter front glass and reflector, fitted into a pistol grip mould with an integrated battery compartment. The result is a unit that sits comfortably in the hand, and in such a way that the inevitable buoyancy caused by the large air-space in the reflector unit is balanced by the weight of the battery pack.
One thing I like about the RCD is the rubber shroud around the front that protects it against the inevitable knocks it will suffer underwater. I also admired how it is prevented from being switched on inadvertently, and especially liked the way the battery compartment is secured shut.
Instead of screwing the unit together by tightening up onto the major sealing O-ring, the battery compartment is clamped shut by operating a cammed lever at the unit's rear. This obviates any tendency for the O-ring to twist or even get moved from its slot.
Anything with an airspace that you take underwater is bound to flood at some time, so any saving of wear and tear on this vital but vulnerable bit or rubber must be a bonus. In fact, I am starting to see this unit offered in many of the hire departments of dive centres around the world.
The Ikelite RCD takes four alkaline D-cells to give a burn-time of five and a half hours with a 7.5W bulb, which must be enough for a one-week diving trip. It produces a bright but fairly narrow beam for its type.
A slightly brighter and broader beam is provided by its more expensive sibling, the Ikelite RCD Rechargeable, with a more powerful 19W bulb. This exchanges a shorter burn-time (75 minutes) for the cost saving of a rechargeable unit. However, the higher initial cost must also be taken into consideration.
The Ikelite RCD costs £51 including batteries, and the Ikelite RCD Rechargeable costs £130 including charger.
Oceanic SW, 01404 891819.
Sausage with skirt
The Buddy (closed end) surface marker buoy: improved model rolls up nicely, and a 20cm skirt reduces air spillage during inflation.
Buddy surface marker buoy (£29.95).
THE Buddy Late-Deployment Surface Marker Buoy was a close runner-up to the Mares MR22 Ruby and Scubapro G500/Mk20L regulators in the Diver Awards for "Innovation of the Year".
It is by no means a new idea, but AP Valves has improved on its original design and now it rolls up nicely, whereas the former design proved a little bulky to stow.
It is a long fluorescent red sausage (around 120cm x 20cm) with a 20cm skirt at the open end. This discourages air from spilling from it when you fill it at depth using your regulator.
The trick is to unroll it and make sure it is floating uninflated above you. Putting a regulator mouthpiece into the open end inflates it enough to send it on its way to the surface.
The air expands on the way up, fully filling it by the time it reaches the surface from, say, 30m.
The clever part is that a restriction prevents the air from escaping once it has bobbed clear of the surface, so even if the line is not kept taut it still signals your presence.
Did I mention lines? Naturally, all SMBs are attached to a line and some form of winder. I prefer to deploy such an SMB when I am at depth and able to tie my winder off to something secure. That way, if the winder jams the buoy is stopped in its tracks rather than dragging me up with it, which is a risk when deploying an SMB with a line and winder from mid-water.
In such situations it is safer to attach the buoy to a suitable length of narrow webbing, which can have a small weight attached to its other end. If you are at 10m, you drop 10m of webbing below you and as the inflated buoy hurtles upwards you let the webbing run through your grip.
The Buddy SMB has a strong loop of webbing securely attached at the lower end for your line or webbing, and a pull dump allows air out of it so that you can roll it up again. To keep it neat, there is a press stud.
The Buddy SMB (closed-end) costs £29.95 excluding winder and line.
AP Valves, 01326 561040.
Appeared in DIVER - June 1998
