DIVER TESTS

March 1996




What's got wings and flaps a little?


The answer is: DiveRite's Transpac Sport Wings, a stab jacket aimed at leisure divers. John Bantin liked it.


While DiveRite's double-bladder Transpac (Super Wings) stab jacket finds much favour among the tech-diving community, its simpler, single bladder form, the Sport Wings, is more applicable to ordinary leisure divers.


It uses the same harness, complete with soft backpack. This harness proved very comfortable. It has a wide waistband, adjusted with a weightbelt-type buckle. The shoulder straps were instantly adjustable, which made getting in and out of the kit both in the water and air-side very easy. Their broad, padded, facings are prevented from pulling apart under the weight of a tekkie's equipment by a narrower strap and Fastex buckle. The harness has eight large D-rings, together with six smaller ones, for dangling accessories.

Should you have chosen to dangle additional gas cylinders from the harness, there's a jockstrap and 'Prince Albert' ring which will stop the weight of four cylinders from tipping over your head during a quick head-first descent. I did without it, but then I was mainly using a solitary aluminium 12-litre cylinder!

This harness uses an air cell interchangeably with the two other air cells available for use with the Transpac system.

The air cell for the Sport Wings forms an inverted U-shape at the diver's back when fully inflated, and provides around a maximum 19kg of lift. Air is fed by a conventional corrugated hose, which also acts as a shoulder dump when tugged on. The dump is positioned crucially at the very topmost point in the buoyancy bag. There is also a dump valve at the lowest point on one side of the bag, which can be used in case of inversion or for draining out unwanted water after a dive.

The single cylinder I used was securely held in place by double cambands and 5cm webbing, and a third (12.5cm) strap acts as a carrying handle. It's finished in tekkie black of course.

Very reminiscent of the early 1970s Watergill At-Pac, (see BC Myths, Diver, February), I can personally confirm that this BC was a pleasure to use because, with a wetsuit, it put the buoyancy just where it was needed - squarely in the centre of my back.

The unfilled bag may have looked a little untidy under water, as it appeared to want to flap a little, but I detected no undue drag. Although, undoubtedly, there was a pronounced tendency to tip me forward in the water when I was at the surface with it fully inflated, this was no great problem. It wouldn't happen if used with a weightier twinset.

With a drysuit, it was better balanced at the surface. The buoyancy of the suit, combined with the weight of the cylinder at the back, countered any push forward, and the uncluttered front meant easy access to the suit inflation valve during the dive.



Sonar you know ...

Who can honestly deny that they'e been on dives which were only in the 'vicinity' of the wreck they were supposed to be visiting? You know the scene. The shot is dropped in, perfectly positioned by the skipper, but you and your buddy faff around so long that you miss the line, and the tidal stream sends you away from both it and the dive site!

Well, now your enterprising dive shop manager is able to sell you exactly the right gizmo to save you those embarrassing entries in your log-book. Called the Dive-Trak or Mark-Trak, it's a system of beacon and receiver for use under water. The difference between the two types is merely range and duration. They utilise the latest underwater sonar technology.

A beacon sends out a series of 'pings' and the receiver unit responds by showing a series of lights according to the signal strength received.

Both units are the size of small underwater torches (17cm long; 5cm in diameter), and are made of polycarbonate. Both clip conveniently on to a weightbelt and are designed to work in depths exceeding 180m.

The beacon unit is turned on by rotating a collar and deployed by attaching it to a point under water where it will be able to send out its signal without being obscured. There is an eyelet in the end of the unit for attaching it to the shotline, and the buoyancy of the unit will make it float vertically in the water.

If you're going to deploy it already attached to the shot-line, you'll have to estimate how high up the line from the shot will be best. Better still, get the first pair of divers (who, one hopes, are clever enough to find their way down the shotline to the wreck) to deploy it for you.

The searching divers, armed with the receiver unit, also switched on by turning a collar, who are by now lost in the murk, simply pan it around until its indicator lights (up to eight in a row with Mark-Trak), showing the direction in which the beacon lies. Another indicator light indicates that the unit is turned on but may not be receiving a signal.

Of course, a more intelligent way of employing this system is to mark the shotline by deploying the beacon yourself and then use the receiver unit as a way of finding your way back to it.

If you are repeatedly diving the same spot, you could leave the beacon in place and working, so that you can easily return to it. That is, if it doesn't get stolen in the meantime!

The beacon battery will last up to 20 days if used with a 9-volt lithium battery. With a 9-volt alkaline battery this duration is halved. The Mark-Trak has a switchable fast/slow adjustment for the 'pinger'. Setting it to fast will halve the duration of the battery again.

The horizontal range of the beacons varies from 220m with Dive-Trak to around 330m with the Mark-Trak. This, naturally, is affected by obstacles between the receiver and beacon. The system cannot see through boulders or bulkheads. This is why it is important to attach the beacon to a point on the shot-line which is high enough above the wreck.

If you've ever spent a dive wandering around the sea bed, exchanging shoulder shrugs with your buddy because you've no idea in which direction the wreck or the shotline lies, you will probably welcome the Dive-Trak beacon and receiver (left), a sonar tracking device. The price (£485-610) is another matter..



Favor of the month

The latest offering from popular Finnish diving computer manufacturer Suunto is the Favor. It slots into the range above the value-for-money Companion, but below the top-of-the-range Solution and Eon models. The new model uses a similar display to the Companion but, whereas the Companion is not really suitable for decompression-stop diving, the Favor shows stop depths and times when they are appropriate.

Hitting the water turns the computer on. Actual depth and expired dive time are displayed permanently, along with remaining no-stop time, which is counted down from the last 199 minutes. Maximum depth achieved and the water temperature are alternated in smaller figures. Remaining no-stop time is also displayed in graphic form, with up to five bars appearing alongside green and yellow zones.

Once the diver has run out of no-stop time, a depth ceiling is displayed alongside the total required ascent time (including stops). At this time a small upwards arrow suggests you ascend. When you reach the ceiling depth a second, downwards-pointing, arrow makes a wineglass effect and indicates you should stay where you are. I hope no user gets to see a solitary downward arrow!

If you ignore a stop for more than three minutes or you did a dive which required you to make a stop deeper than 12m, the ascent time and stop ceiling indicator are sent into convulsions and start flashing. The allowed ascent rate is 10m per minute and this is controlled by watching the ascent rate indicator graphic and keeping it in a similar green zone. This graphic is sent into the yellow zone when the diver exceeds 11 m./min. and the word SLOW blinks in alarm.

In surface mode, the Favor displays the elapsed surface interval since the previous dive, the maximum depth achieved and the dive duration. This is alternated with a display which shows the total desaturation time remaining. There is a no-flying icon which also appears as necessary.

Menu-based functions include 'log-book mode' which summarises the nine last dives, and 'history mode' which remembers 999 previous dives done with the Favor. Altitude adjustment, which must be done manually, can be used to enter an allowance for a personal safety margin (for example, this can vary the no-stop time for a 30m dive from 17 to 11 minutes). The date and time setting can also be changed.

For dive planning, fingering a pair of contacts causes the display to scroll through a set of depths and allowed no-stop times, taking the previous dives into consideration.

It works on a small lithium battery which should be good enough for more than 3000 hours' use. There's a battery power and low battery warning which will appear as appropriate. Like the Suunto Companion, the Favor cannot be interfaced with a PC to produce print-outs of the dives recorded.

There was a time when an instrument like this was considered the acme of electronic wizardry. Now it represents the standard machine which no diver should be without.

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Italian jobs

There was a time when 'Made in Britain' meant something and foreigners copied us. Now, we've got used to Rover cars being made by Japanese or German companies.

It should be no surprise to find that the new Cutter fins, marketed by that bastion of British diving equipment manufacturers, Typhoon, are actually made in Italy. And why not? The Japanese and Germans seem to make the best cars, and the Italians seem to have mastered the art of making the best fins for divers!

The Cutter's designers appear to have borrowed the profile of Cressi Sub Frog fins, the shape of Mares Plana Avanti, and the flexibility of the new Technisub Idea, and have come up with a fin design which seems, if anything, a little on the dull side. That said, Cutters are well made, from two synthetic thermoplastic materials which are well integrated. The full-length foot pocket is extended to form what Typhoon call a "flexible central spike" in the long (42cm) blade.

Now this is not a spike in the sharp-pointed meaning of the word. No, it's more like a multitude of sessile leaves of rubber arranged closely upon a common axis. The soft rubber-like compound which forms the middle section of the fin blade merges with a more robust plastic. This gives a lot of longitudinal flex together with a little lateral flex and hence the water-scooping effect well known to those who may use one of the aforementioned Italian brand leaders.

The exaggerated dip of the fin blade puts it at exactly the right angle for efficient finning technique in a way that puts the down kick load on top of the foot (a la Cantona), and I found the pair I tried were unobtrusive enough in use to be able to fit them and forget them.

Easily adjustable straps with quick-release buckles complete the package. Available in two sizes (s/m and m/l) and in three colours (black, blue and lime green) they represent good value at less than £50 per pair.



What flashes intermittently and glows in the dark?

The latest Princeton Tec Aquaflash (above) has a translucent cone which is luminous. It gets charged up by the light from the bulb (powered by two AA batteries) and glows green. What's the advantage? It's easy to find in your bag or in the bottom of the boat in the dark, and it makes it easy to find the diver who's wearing it under water, even if the flash has been turned off. Complete with adjustable wrist lanyard, it costs £15.25.




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