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

Last autumn, in Italy, I watched Gianluca Genoni take a few deep breaths, hold one, and then sprint down to 125m and fin back up again. He was wearing the latest thing in free-diving fins.
     You've probably seen something similar. These are fins so long that they look like a couple of boogie boards protruding from some rubber shoes.
     You might also have noticed that some resident dive-guides in far-off places like to use free-diving fins, even though they are really inconvenient in confined spaces - and that includes coral reefs, pick-up boats and the area between the ends of their fins and my face. Goodness knows how they would manage if, like us travelling divers, they had to pack them in a bag.
     I recently took a pair of such inconveniently large fins with me to Egypt. Yet they fitted easily in my dive bag. No, I have not started using a windsurf-board bag for my diving gear - it was a pair of the new Sporasub Variant fins I was carrying.
     Genoa is the home of the diving division of HTM, the Euro-conglomerate that includes Mares, Dacor and Sporasub. With a track-record like that of its stable-mates, you wouldn't expect Sporasub to produce a fin that had no "unique selling proposition", would you?
     These fins use four patented design features, including an optimised pivoting blade giving a variable angle between it and the foot-pocket, and a revolutionary interchangeable blade system.
     The Sporasub Variant design provides for an enormously long fin by making its blade, which measures 64cm from the tip of your toe to the tip of the fin, detachable. The foot-pocket section and the blade interlock and are held in place by a clover-leaf key section and a large three-pronged split-pin.
     That's how a pair came to fit easily in my bag. You can even buy a choice of blades so that, rather like a golfer, you can choose the right one for any given job: "Pass me a number 4. It's going to be a tricky one!"
     In fact I was sent only two types to try. The manufacturer didn't bother to send me the most expensive blade, with a special web of carbon fibres that makes for extreme lightness. It is said to exhibit exceptional characteristics. This blade is evidently going to be the choice of free-diving champions.
     For lesser mortals like me there is the Combi blade, constructed from a highly flexible technopolymer, and the Master blade, made from a yet more flexible elastomeric technopolymer which is said by the manufacturer to be ideal for free-diving in shallow water or surf. I was drawn to this latter type.
     If you treat yourself to a pair of these fins, you must promise me not to use them for wreck- or cave-diving, and you must certainly avoid going near any precious and endangered corals. Keep them only for chasing whales, whale-sharks and the like out in the blue.
     The pair sent to me to try were not my size, so I went diving with Jan Ellingsen, who comes equipped with the sort of short muscular legs that can get the most out of this type of fin. We were using scuba rather than free-diving but I thought we could still find out if they worked and they did.
     "I wasn't really finning very hard. In fact I thought I was going rather slowly. I must get myself a pair." So mused my buddy when we surfaced. All I could do was gasp for breath, wait for my heart to return to a more normal 60 beats a minute, and grip my aching shins.
     It had been such a trauma trying to keep up with him to get the photographs that I was exhausted - and I was using my favourite scuba fins too. So I guess we could conclude that the Variants shovelled the water all right!
     Sporasub Variant fins cost £52 with Combi blades, £62 with Master blades and £195 for the carbon-fibre versions.

Expanding the choice of technical BCs
I have never seen myself as a technical diver, more a logical diver.
     When I started diving independently of clubs and dive centres in the early '80s, from my own boat and accompanied by perhaps just one other diver, I started having to think about redundancy. So I decided to take a second complete aqualung with me, in the form of another cylinder and regulator, the whole configured as a twinset. And by chance it had a manifold with an isolation valve, although for all intents and purposes I could have used independent singles.
     Today, I have to admit to a certain amount of envy for those diving alongside me with twin cylinders when I have only a single. I am getting to the point at which my air no longer lasts as long on a dive as it once did, and because I have got used to wearing twins simply for the purposes of comparing regulators during dives, I have probably stopped being so careful with my consumption. When you have more than enough air, you tend to breathe it and be damned!
     Of course, if you're wearing heavy steel cylinders, as I was all those years ago, true redundancy includes a second BC bladder. Although there are those who for some reason abhor the idea, a well-designed (dare I say it?) "technical" diver's BC can include this feature without becoming too intrusive.
     The Northern Diver Sea Eagle is a twin-bladder BC with a stainless-steel backplate hidden behind a generous comfort cushion.
     It has two direct-feed controls and corrugated hoses, 10 stainless-steel D-rings and two pockets, each big enough to hold a spare mask or delayed SMB.
     Mine was supplied with two sets of twin cambands for twin tanks, although I suppose you could use it with a single 15 or 18 litre tank fitted with a Y or H-valve (for two regulators).
     Because of its steel backplate, the Sea Eagle is no lightweight. It weighs in at close to 7kg, which is something to think about if your journey to the dive site involves more than a car ride.
     The two cambands slipped quickly and easily over the two rented and independent cylinders I was using. On my back, I found it very comfortable and was able to stride down to the water's edge, even if my return journey after the dive included a few feeble stumbles.
     The corrugated hoses tended to be pulled back so that they seemed a little short, but they certainly didn't get in my way, and the velcro-covered epaulets made sure that the hoses were to hand when I needed them.
     I made a series of shore dives, which meant 15-minute swims out to the point at which we dropped down. I found it very convenient to swim on my back with one bladder fully inflated. The over-pressure valve on each bag is positioned at the lower back in conjunction with the dump there, so when this burped it felt as if I had eaten too many beans for breakfast! Naturally you use only one bladder and keep the other as an emergency item.
     Under water, the elasticised cords that restrained the buoyancy bags kept everything from flapping and it all seemed rather neat. At the same time there was no way in which they could restrict full inflation of either bag or both. I always felt that my body was at the angle I wanted, and I had enough buoyancy to keep my head well clear of the water once I surfaced.
     Of course I had to endure the scorn of a "proper" technical diver, who told me that the Sea Eagle drew heavily on the design of the OMS wing. So what's wrong with that? Are other manufacturers not allowed to give us choice in the marketplace?
     I just take the gear diving and find out by experience, and this technical diver's wing provides a useful alternative in an area in which there is not too much choice.
The ND Sea Eagle costs £325

Another way of calling you home
Electronics have revolutionised navigation of ships, planes and even cars. However, GPS doesn't work under water, as H2O absorbs radio waves, so designers of electronic navigators for divers have turned instead to sound waves.
     The idea of a sonic sounder that responds to a transmitter and indicates the way back to the boat anchor or shotline is not new. I tried one three or four years back called the Sonic Seeker.
     It was not a resounding success, however, and fellow-passengers on a liveaboard enjoyed watching me having to hunt for the transmitter in the dark by the red light it emitted, after I had lost it during a day-time test. The Sonic Seeker might have been cheap, but I've found more effective devices in Christmas crackers!
     Then came the Uwatec Neverlost. It worked, but the beacon is so expensive that I would be reluctant to leave it unguarded, especially on a shotline. You never know who might be hanging about. The seeking unit is also very big (about the size of a good underwater lamp). While it worked perfectly, it tended to dominate the dive.
     The new Xios EyeSea Wreck Diver is a more economical package and the seeker unit can be strapped to your wrist. It's about the same size as the earliest diving computers. Instead of having to scan round to get a signal, it provides the diver with a permanent LCD display, rather like an electronic compass. Barring interruptions, it always indicates the way back, even if that way is behind you, unless you block its view of the transmitter beacon.
     A little anchor icon moves round a circle on the display. Line this up with the lubber line and you're on your way back. It also displays a calculated distance-to-beacon up to a kilometre! I didn't swim that far from the boat, but I guess it gives good warning if the boat leaves without you - as has been known to happen.
     The lesser distances I swam seemed accurate enough, except on one dive during which I saw more than 600m displayed at a time when I could clearly see the beacon. That's what I call good viz! It must have been caused by one of those anomalies one is always reading about.
     You need to deploy the transmitter beacon sensibly. Hanging at about 15m proved perfect, but being nearer the surface cluttered the receiver/seeker with reflections from its underside. Being upside-down also renders it useless, and hang it too deep and underwater obstructions will block the sonic waves.
     You must initiate the receiver/seeker to the beacon before diving. If a lot of you plan to use a single beacon, all your receiver/seekers must be initiated at once and left switched on until all the dives have been completed. The manual suggests placing the beacon and receivers/seekers in a bucket of water to do this, otherwise everyone has to hang off the boat with the units under water, which is not ideal.
     You have to learn to fly on instruments. It's like when you first use a compass - you often can't believe what it's telling you. Even the most experienced diver can get disorientated, so you have to trust the EyeSea or there's no point in having one.
     I didn't much like the method of switching on the receiver unit by tightening the battery compartment. This seems to offer users the chance to flood the compartment, and after one obviously inadequate freshwater rinse I had to get the pliers on it to turn it on again.
     The Xios EyeSea Wreck Diver with one transmitter beacon unit and one receiver/wrist unit costs £399. Additional wrist units cost £269.

Why Bare won't have you in stitches
People are always going on about the special difficulties of diving in British waters. "If you can dive in Britain, you can dive anywhere," they say. Well, the waters around Canada aren't that clever, either. They are cold, and there are tides and currents! You also run the risk of getting eaten by a grizzly or a polar bear when you come up.
     So a drysuit from British Columbia has just as much credibility in my book as any made in Britain. The Canadian Bare CD4 Pro neoprene drysuit is in fact made in Malta and distributed by Suunto of Finland, but then it's not that warm in Scandinavia either - or the Med in winter for that matter.
     Bare suits are made by FitzWright Europe, part of FitzWright of Canada, and owned by Suunto. "No-stitch" technology is used to make these neoprene suits, with seams glued and taped only. Is this why they are called Bare?
     The CD4 Pro is made of 4mm neoprene with a cross-shoulder zip, comfortable 3mm neoprene neck seal and long latex wrist seals.
     Kevlar knee-pads and light- and radar-reflective patches are standard. The suit tested came with 7mm neoprene heavy-duty boots and a thigh pocket. A swivelling inflation valve is located at the centre of the chest and a low-profile constant-volume auto dump on the upper left shoulder.
     So what do you want in a drysuit? The first thing I want is to be kept dry! Then I want a suit that allows me to swim without restriction or causing friction burns to any part of my body.
     Finally, I want a suit that makes me look like a good advertisement for our sport. I don't want people taking one look at me and thinking that diving is simply too uncomfortable.
     You've probably noticed that I never mentioned keeping warm. That's normally the job of the undersuit, though a neoprene drysuit does offer some inherent insulation of its own.
     One summer day I headed for Wraysbury Dive Centre's lake near London, armed only with the minimum-weight undersuit. I was tempted to use this neoprene suit alone against my bare skin but decided against for reasons of comfort rather than insulation.
     Neoprene suits are rarely dry. Don't expect them to be and you might be agreeably surprised. The Bare CD4 did let a few trickles in past the neck seal, even though it was scalp-wrenchingly tight to pull over my head.
     The seal is a tube of neoprene which has been inverted rather like an inside-out polo-neck to obtain the best contact possible, and it's very comfortable once properly round the neck.
     The latex wrist seals certainly held the water at bay. In fact, had the suit flooded, it wouldn't have been the end of the world. I would have used it as a wetsuit!
     As it was, I just felt like a baby that needs a nappy changing.
     If anyone asks me which is the best drysuit, I usually say: "One that fits you!" I was quite lucky that the off-the-peg Bare CD4 Pro sent to me did fit. So I quite enjoyed my outing, even if the water was not at a chilling winter temperature, when being Bare-suited would definitely be preferable to being bare-arsed!
     Available in a range of off-the-peg sizes, Bare drysuits cost from £550.