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DRYSUIT
THE ONGOING DEBATE ABOUT whether you should use your drysuit or your BC for buoyancy control amazes me.
The simplistic idea is that as BC stands for "buoyancy compensator", that is what should be used. Air in the suit to compensate for squeeze and air in the BC for buoyancy control, runs the argument. It is as if its advocates are unaware of why the BC was invented in the first place.
People are incompressible. It doesn't matter how deep you go, you keep the same dimensions. The same cannot be said of your neoprene wetsuit. As you go deeper, the integral gas-cells within it get compressed and so displace less water. The effect is to make you progressively heavier. So if you use a wetsuit (or semi-dry), you add air to a BC to make up the difference.
If your suit could be kept at constant volume, this effect would not occur. Putting air into your drysuit as you go deeper keeps it at constant volume, so your buoyancy is controlled.
The BC then becomes redundant and for use only as additional surface support or as an emergency buoyancy device. This assumes that you're diving within a reasonable margin of neutral buoyancy when you enter the water.
A lot of people use far too much lead to "get under". If you organise your weights so that your eyes break the surface when you inhale and you sink when you exhale, you will need only to exhale in order to start a descent.
"Ah," some of you say, "I need a lot of lead because I use a neoprene drysuit." Well the Typhoon TCS is a neoprene drysuit and I found that, although there is definite compression at depth, down to 40m it is not enough to need to call the BC into play. That's because it's made from 3mm neoprene that has already been compressed.
The good thing about neoprene is that it has some insulating properties of its own, so you can use a thinner undersuit. Use it in the Red Sea in winter and you probably need only a T-shirt. It keeps you as warm as a wetsuit but, of course, you are still dry when you climb out of it.
At the same time, it is much more sleek than a membrane drysuit. I found I could swim as unimpeded as in a normal semi-dry. At Wraysbury Lake I used the full Weezle undersuit, which squeezes down to fit the available space.
Securely zipped up, I strode out purposefully. My will faltered only when I looked at the icy water and decided that a dip was beyond the call of duty, however good the suit was going to be!
The Typhoon TCS is a pretty standard design. It has a cross-shoulder zip hidden under a neoprene flap, neoprene wrist seals and a latex neck seal protected from the flush of cold water by a neoprene collar. It has strong rubber boots lined with neoprene and tough rubber knee-pads.
There are no-slip patches at the shoulders. A zipped thigh pocket is big enough for a small reel but not big enough to act as a sea-anchor.
I have always been tall and skinny and my first drysuit enveloped me in folds of material, because to get the height I had to buy one that fitted someone with a 52in chest. Manufacturers have now got a handle on the new generation of people (I was obviously one of the first) and I now find I am a standard size, even though clothes I bought in the '70s still fit me (I'm waiting for the fashions to come back.) The TCS fitted perfectly.
I used the suit with a 15 litre steel tank and minimal-size wing-style BC for emergency buoyancy and surface support. Did I put air in the BC for buoyancy control? No. I kept the suit neutral by inflating it via the Apex rotating inflation valve at the centre of the chest on descents, and vented it using the Apeks automatic constant-volume valve at the shoulder, being careful to keep this at the highest point on ascent.
So how do you achieve this perfect state of equilibrium? It's simple. Get your buoyancy right before you start, and bear in mind the loss of weight due to the gas being exhaled during the dive. The average weight of breathing gas consumed during a dive with a standard single tank is about 2kg.
If you use multiple tanks and expect to consume a fair weight of gas on the dive, you will need to put on extra lead to compensate for losing this weight. In that case, you might well need to add gas to the BC in addition to the suit.
The Typhoon TCS comes in a wide range of eight off-the-peg sizes and costs £499.
Typhoon, 01642 486104, www.typhoon-int.co.uk
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- Perceived buoyancy changes
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FINS
THE LAST PAIR OF FINS I TRIED from the long-established French manufacturer Beuchat was, to be frank, not very good. They were strongly made but failed spectacularly when lined up against industry standards such as the Mares Plana Avanti Quattro.
This new fin design, the X-Jet, is of much lighter weight. It reminds me of the well-liked Cressi Rondine A, in that it has a crisp and rigid paddle blade with edge flutes and shaped vents that do well to stop side-slip during the downstroke.
I took them for a week's diving in the Red Sea aboard the Blue Seas liveaboard and, although I was the guest of Big John, who not only handles the Blue Planet liveaboard holiday business in the UK but is also now distributor for Beuchat,
I was neither daunted by his presence nor influenced by any input or heavy sales pitch from him.
I simply put the fins on and went diving with them. Of course, he also dived with a pair.
These fins have generous foot-pockets that encompass nearly all of the foot and so do not impart any loading onto the user's ankles. I felt I was able to shift plenty of water, thus pushing myself forwards.
I confess that I was never subjected to any strong head-on currents. However, as usual I was pushing my big camera rig around but never had cause for concern over any inability to make forward progress.
If I had any cause to be niggled, I would say that the strap buckles were less efficient than they could be, often allowing the strap to loosen - not so much as to cause concern during
a dive, only on the boat's dive platform prior to plunging in.
I would suggest replacing any rubber fin-strap and buckle with stainless-steel spring straps anyway.
Now, I am not suggesting that these fins are in any way better than the most efficient and expensive fins available in the shops. However, they are available at a reasonable price and they work.
The Beuchat X-Jet fins are available in four colours and four sizes and cost £50 per pair. There is also a full-foot version suitable for use without boots at £35.
Alpha Distribution 01709 515157, www.beuchatuk.com
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+ Effective fin design
+ Economically priced
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- Strap buckles need improvement
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COMPUTER
WE RECENTLY REVIEWED THE SCUBAPRO SMART TEC computer in these pages. The newer Smart Z is, in common with its similarly oil-filled Smart Tec brother, a hoseless nitrox-integrated computer connected to the high-pressure port of a regulator first stage by means of a small radio transmitter.
The difference is that it integrates with only one transmitter and so is cheaper.
You can set one of four levels of micro-bubble suppression to the Smart Z's calculations. This is useful during a multi-dive, multi-day trip, or you can use the Smart Z with the old faithful Buhlmann ZH-8L algorithm with which it comes set by default, straight out of the box.
I first used it set to Level 1 (L1). This gave me extended stops in the 3m and 6m range after a satisfyingly long twin-set dive on the wreck of the Rosalie Moller, with maximum depths in the order of 47m.
In fact you can ignore the extended deeper stops, which are indicated as "level" stops on the display, and the Smart Z will simply extend the length of the mandatory deco stops , which will be shallower instead. It's like ignoring the optional deep stops on the Suunto D9.
I had the two computers on my wrist alongside each other, and the actual required deco amounted to much the same.
Jean-Paul, the dive guide aboard Blue Seas, told me that he used his set at Level 4, so I decided to do the same on a dive to the seabed near the El Mina, the wreck of an Egyptian patrol boat outside Hurghada harbour.
The wreck is around 30m deep and I was rewarded with about 14 minutes more deco at 3m than the previously similarly performing D9. Boring!
These "level" stops are indicated first at 3m and later at 6m and so on, but if you take your time meandering towards
the surface they clear off before you get there. It is very important, however, to be sure to read your Smart Z correctly. The level-stop figures sit in lieu of the deco-stop figures and the icon that differentiates between the two is quite small.
In fact the main criticism users have of this system is that once level stops are indicated, the remaining no-stop time is not. This in effect means that you tend to think of the optional level stops as mandatory deco stops and cut short your dive.
This happens only on the cusp between the two, but once into deco-stop diving proper, all becomes clear. However, that's not so cool for those who like to keep to no-stop diving.
Setting up the computer is straightforward, though finger-lickingly irritating. It really is time Scubapro Uwatec went over to buttons, along with a user-replaceable battery.
You can preset maximum ppO2 parameters between 1.0 and 1.95 bar and, if you like to go deep, use the computer in "gauge" mode, whereby it will happily go to 120m.
For us nitrox divers, it permanently displays the oxygen percentage set which it remembers between dives. It displays CNS oxygen exposure as a percentage.
It shows actual depth, maximum depth achieved during that dive, and remaining no-stop time or level-stops or required decompression stop depths and times.
I found it easy to pair with its transmitter and it never lost the signal.
It shows tank-pressure and remaining-gas time based on the depth of the dive and the previous breathing rate during the dive. It shows minimum time needed to achieve the surface after a safe ascent and any stops. Make sure your remaining-gas time is longer than this.
It also helps you to manage your ascent with an ascent-rate display that is shown as a percentage of the maximum allowable. The ascent rate itself is variable according to depth.
Choosing the micro-bubble suppression setting is a matter of personal preference. Supremely fit as I am, I chose L1. I guess those who have a tendency towards obesity should set a higher level, and those who are getting on a bit (oops, that's me!) should do the same.
I enjoyed using the Scubapro Smart Z. Apart from that one extended and probably unnecessary hang, I couldn't fault it for the way in which it delivered the information. It makes a good choice for those who want a single-mix nitrox-integrated computer.
The Smart Z comes bundled with Smart Trak software for downloading your dives and customising your computer. Complete with its transmitter, it costs £649.
Scubapro 01256 812636, www.scubapro-uwatec.com
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- Not cheap
- No guidance on choosing micro-bubble suppression level
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BC
I used the Seac Sub Icaro wing recently and voted it a resounding success. Fully inflated at the surface, it put the buoyancy low down and me high above the water. The Icaro Tech has a similar effect and the same company makes it.
Obviously intended for use with twin cylinders, the Icaro Tech is claimed to be just as suitable for use with a single. I used it with a heavy 15 litre steel cylinder while my buddy, Malin Svedberg, the dive-guide from Tornado Marine's Diamond liveaboard, took turns with me to use it with a conventional 12 litre aluminium cylinder.
The wing forms a narrow U-shape and is of double-bag construction. It is constrained by an elasticated cord threaded through the front of it. The whole is attached to a fantastically lightweight aero-quality aluminium backplate, which in turn has two individual padded cushions and a continuous webbing harness threaded through it.
The overall result is a wing-style BC so light that I had no hesitation in packing it in my dive-bag alongside another I was already taking away with me.
The Icaro Tech's harness has a number of D-rings mounted on H-clips and it is important to make sure that these are positioned where you need them, as they can make tightening the harness, once you're wearing it, impossible.
That's because these D-rings, once positioned, are not easily moved. While this is a good thing, it can be significant when moving from drysuit to wetsuit and vice versa.
You adjust the whole thing by pulling tightly on the waist-strap and fastening it with a standard weightbelt-type stainless-steel buckle.
I could not immediately see how to adjust the 5cm-wide sternum strap so that I could fasten it by its pinch-clip. Both male and female parts are stitched to the main harness and seemed impossible to move, so I used the Icaro Tech quite comfortably without it.
On the other hand, Malin was able to hoist the set high on her shoulders so that she could pull the shoulder straps together towards the centre of her chest and in such a way that the sternum strap met and clipped together. I put it down to her having the same chest measurement as me but, with her smaller rib-cage, her body parts are arranged in a different way!
She reported that it made the rig remarkably comfortable for her, affording an unusual degree of freedom of arm movement. In fact she has made up her mind to treat herself to an Icaro Tech - that's what I call voting with your chest.
There are two cambands, one above the other, and a carrying handle. The Icaro Tech is clearly happier when used with twin tanks.
I couldn't see how, in the manner supplied, the elasticated cord restrained the buoyancy bag. It simply caused internal crinkles that tended to trap the air inside so that, as I moved around, the air I used for buoyancy-control moved around within it, complete with disconcerting gurgling noise.
It also affected my trim, as there was a slight delay before the air got to the right place. It was not a disaster, but if I owned an Icaro Tech I would either shorten the elastic cord so that the buoyancy cell was crushed up far more under water, or simply remove the bungee altogether if I was using twins. The manufacturer gives you the choice.
There are those who decry such a bungee'd restriction on the buoyancy-cell, claiming that it can dangerously restrict its full inflation. Others rubbish this idea and like the way, with the cord suitably tightened, the cell is reduced to limit the amount of drag it causes while swimming. We ended up caught between the two stools, and used it as it was supplied.
I believe that, with twin cylinders, allowing the bag to flap is not an issue and, with a single, the tightened elastic strap still leaves plenty of room to inflate the wing effectively at the surface, without reducing maximum lift significantly.
Otherwise, this wing was perfect! Like its little brother, surface support is very effective because the bag inflates well and low down at the surface, leaving only a small section high and behind your neck for buoyancy control under water.
The U-shaped bag has dump valves low down at the back on both sides and, assisted by an easily found toggle on both, I was able to dump air from either effectively.
During head-up ascents, the dump-valve at the top of the valve worked perfectly. This is operated by a long cord threaded through a flexible plastic conduit to a toggle at the right of the middle of the chest area.
Getting out of the rig was not quite so easy when I was being picked up by a RIB at the surface. With no buckles to break in the continuous loop harness, I found it best to undo the waist-strap and pull the whole thing over my head as I ducked under it. It was no big deal.
So despite neither opting for a fully restrained wing nor an open version without the bungee cord, we both still enjoyed using it. Once again, Seac Sub proves that it is a force to be reckoned with in the BC market.
The Seac Sub Icaro Tech comes in three sizes and costs £449. There is also an optional integrated-weight system.
Beaver Sports 01484 512354, www.seacsub.co.uk
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+ Lightweight wing that could be rigged to suit your style of diving
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- Continuous-loop webbing harness can be hard to adjust between drysuit and wetsuit
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BAG
Airlines are starting to get wise to divers. They insist on weighing our carry-on bags at the check-in. So unless you equip yourself with one of those multi-pocketed safari-jackets and stow all your heavy gear about your person, walking with wobbly legs all the way to the departure gate, you might as well pack it, check it, pay up and be smart!
You are still limited to a maximum all-up weight for any one bag of 32kg because Health & Safety has ruled that anything heavier is unsafe for the poor baggage-handlers. Some US airlines have even reduced that to 23kg.
It you travel economy, going East from the UK, you pay for anything more than 20kg and may as well pack in several small bags. If you travel west through the USA, you can check in up to two bags of not more than the maximum weight allowable for each. There has to be some advantage to passing through George B's new police-state. Personally, I think it's worth paying extra to go the other way to avoid hassle.
Now I've got that off my chest, I can tell you about the Beuchat Off-Shore bag. It's big. It will take all your diving gear. It has enormous self-draining side-pockets that will take your fins and other stuff besides. These are fastened by large pinch-clips. It has a massive zipped centre section plus two zipped front pockets.
Its soft construction means that it doesn't use up all your checked-baggage allowance before you even start packing it. It has wheels and an extending handle and it doesn't fall over when you stand it up. Its outside material has a shiny water-repellent surface that comes in handy in countries subject to rain - ours, for example.
Returning recently from Egypt, I noted at the luggage carousel that someone had inadequately packed a bottle of red wine that had deposited its contents all over my bag.
It washed off in a moment and I was able to send the bag back to the Beuchat distributor without him thinking he'd lent it to a lush. He is very particular about such things! (Who brings back wine from Egypt, anyway?)
So there you have it. A bag that will encompass all your gear, survive a soaking in booze and could cost you a fortune to check in. Me? The last word I heard from the girl at the Excel counter as I left her was: "You'll get me fired!"
The Beuchat Off-Shore Bag costs £129.
Alpha Distribution 01709 515157
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+ Capacious
+ Convenient price
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- Could be heavy at check-in when fully loaded
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