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September 2004 Vol. 30, No. 9   RSS Feed for Undercurrent Issues
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Computer Problems: Part III

air-integrated glitches

from the September, 2004 issue of Undercurrent   Subscribe Now

Air-integrated (AI) computers offer a menu of features, such as calculating remaining air and bottom time by monitoring air consumption. They can even modify the decompression schedule according to the workload. For example, if the computer detects that a diver is breathing heavily at depth, the model considers that the diver is actually taking on additional nitrogen, and may call for shortened no-decompression limits or extra decompression time.

AI models currently account for more than a quarter of new high-end computer sales in the U.S., according to industry experts. Jim Clymer of Suunto says their Cobra is their best-selling computer. Joe Stella, VP of Scubapro/Uwatec, reports that the top four or five selling computers either are air-integrated or watch style (some of which, like Uwatec’s Aladin Air 2, can also read tank pressure through electrical transmissions from the tank valve to the computer).

But they’re not perfect. Our recent poll of Undercurrent subscribers unearthed a number of aggravating incidents involving screwy readouts, battery malfunctions, and loss of tank pressure transmission. (Note: some of these reports involve older models, no longer being distributed. Many are also no longer being serviced).

When Good Displays Go Bad

If a computer’s display disappears or becomes erratic, the causes can be tough to diagnose. Joe DiDia (Novi, MI) has had three Oceanic Data Plus II units fail “with very little dive time on them.” Oceanic replaced each unit in a timely manner. During a trip to Cozumel, one unit failed during the first dive – the display would only flash “On – Off.” On the second day, the second computer failed the same way and two years later, in Grand Cayman, his replacement failed as the others had. Though his warranty had expired, “they replaced the third unit without issue.”

“It’s my experience that more divers lose a dive due
to integrated failure than any other reason.”

Alan Sankowski and his wife (Hoffman Estates, IL) took a pair of Suunto Cobra AIs on the Komodo Dancer and experienced one nonrecurring depth-reading problem with each computer. They dive almost identical profiles and check each other’s computers throughout each dive. “On our fourth dive,” recalls Sankowski, “I was surprised to see my wife 10 feet below our agreed max depth. After we had both ascended a few feet, my computer was reading eight feet deeper than hers.” The crew lent the Sankowskis another computer and during the dive the difference grew until her computer showed eight feet deeper. The computer that registered deeper also showed more nitrogen loading. “It appeared that while the depth readings were inaccurate, all of the algorithms seemed to be functioning correctly,” Sankowski reports. On more than 30 subsequent dives, both computers behaved correctly.

The Sankowskis’ dive shop returned the Cobras to Suunto. No problems were found, and the computers were returned. Says Sankowski, “A large part of confidence in one’s equipment is mental. Since we did not experience any problems in the last 30-plus dives, I’ve become less concerned with the reliability of the computers, and more inclined to believe that the problem was a one-time issue.”

The wrist strap on Bruce Eanet’s (Washington, DC) Oceanic Data Max Pro Air/Nitrox hoseless computer broke when he was getting back in the dive boat Akumal. He didn’t lose his computer and got a replacement strap from Oceanic. But, Eanet says, that for a computer that costs nearly $1,000, “There should be no issue with the band breaking after only three years.”

Hoseless Interruptus

Hoseless AI models rely on a small battery-operated transmitter on the first stage high-pressure port to send pressure readings to the console or wrist-mounted computer. Suunto’s Jim Clymer says that hoseless models are making “steady increases” in share of the AI market. And why not? One less hose to worry about, and one less gauge to fumble with. It’s a great concept … when it works.

Dale Treadway’s (Omaha, NE) Uwatec Air Z 02 wrist model worked fine for two years, until it stopped receiving the signal from its transmitter. He switched to his “old backup Suunto EON” AI, using his Uwatec as a backup. It worked intermittently, but would go for three or four minutes without receiving a signal. He learned from Uwatec that the electronics of his Sea & Sea YS 90 Auto Strobe interfered with the signal to his computer. “Seems reasonable,” he says, since he never had a problem until he began using the strobe.

“The electronics of his Sea & Sea YS 90 Auto
Strobe interfered with the signal to his computer.”

A strobe was also fingered as the culprit when Greg Cruz (Saratoga, CA) reported problems getting his Oceanic Data Trans Plus to consistently connect to the transmitter. “Half the time I would get it to connect and many times during the dive it would lose the connection.” It worked fine back at his dive shop, so they determined his problem might have been due to using a strobe. On a subsequent trip the computer twice worked at the surface then failed at depth. Oceanic sent him a refurbished unit, which again lost transmission at depth. He is now on his third unit, which has managed to stay on during a couple of dives, “Although,” says Cruz, “it reads the water temp at a comfortable 99 degrees.”

Scubapro’s Joe Stella told Undercurrent that electrical interference can be eliminated by moving the computer away from the electrical source. For instance, a retractor can keep a console model away from a strobe or electric scooter. If you dive with a wrist mounted AI, try holding your strobe in your other hand. Uwatec claims that its “unique transmission technology” ensures that if a signal is interrupted by camera or strobe flashes, the signal is reinstated in five seconds. Besides electrical interference, there seem to be lots of other ways data transmission can be interrupted.

Gary Nagel (Greenfield, WI) has replaced his Oceanic Data Trans Plus twice. The first time he used his hoseless Oceanic, in Cozumel, Nagel lost tank pressure transmission. He replaced the batteries – they cost twice the US price, another good argument for always bringing spares – but they didn’t solve the problem. Leisure Pro replaced it without argument. After a second failure and replacement, Nagel said, “Although I always got tank pressure readings at home when testing the computer, it never acted right when I went diving. I decided to crank the transmitter just a little tighter into the first stage. Bingo, end of problem.” Nagel points out that Oceanic’s owner’s manual neglects to mention how tight the transmitter needs to be. “They should include a ‘trouble shooting’ section in their manual. It would stop a lot of exchanges.” He used a wrench for a reliably tight fit.

Mark Berger (San Diego, CA) has gone through three transmitters for his wrist-mounted Oceanic DataTrans Plus. “They were replaced without a problem during warranty,” he notes, but the last one cost him $75. “You never know when they are going to go south. But you can usually tell at the beginning of a dive if you are going to have a problem. (It will not link with the receiver).” Berger says when his tank pressure hits 300 psi, his Data Trans Plus shuts down the time display for the dive and flashes “GAS ALERT” along with depth and amount of remaining air. This usually makes it impossible to time his safety stop. Berger points out that the unit’s time display only has two digits. “On occasion I like to do a shallow dive that will last more than 99 minutes,” he notes, “and that is as far as the computer can record.” Otherwise, he finds the computer easy to read with lots of information.

Anticipating a trip to the Turks & Caicos, Kim DeWitt and her husband (Evansville, IN) bought new Oceanic AIs. They found that at times, the signal was lost, “and it required that the unit be held near the main transmitter for a minimum of four seconds to reestablish communications.” This required a “contortion with full gear and getting your hand up over your head backwards and holding it steady for four seconds.” The DeWitts also found that after the computers went into sleep mode between dives it was sometimes necessary to get them wet before they reactivated. They’re now using Suunto Cobra console models.

Donald Wilson’s wrist mounted Suunto Vytec occasionally locks out after the pressure drops to zero when changing tanks. The display reads “fail,” and he is unable to reset the computer for several hours. It still shows depth, temperature and time, but does not show tank pressure, nor does it record and save dynamic dive details. “The owner’s manual, like all owner’s manuals, a semi-disaster, does not show the way out of this dilemma, nor has anyone at Aqualung [Suunto’s U.S. distributor] been able to help me,” says Wilson.

Such experiences have soured some dive professionals like Randy Jordan, proprietor of Jupiter Dive Center in Florida. Jordan makes more than 600 dives a year, and is familiar with all kinds of equipment. “I often see people with integrated units miss dives because their unit went out. This means they lost their computer and their submersible pressure gauge.” In fact, he adds, “it’s my experience that more divers lose a dive due to integrated failure than any other reason.” He has spotted many hoseless integrated users turning their tanks on and off a couple of times before the transmitter makes contact. Although divers say they like the compactness of a hoseless integrated computer, Jordan points out that they often have to carry a backup pressure gauge, in case the unit fails. He says, “I carry several lines that have integrated units and I have chosen not to sell them.”

Dive industry marketers, of course, defend the reliability of their hoseless models. Uwatec’s Stella says, “We get little negative feedback on our hoseless category,” and adds that his company, one of the first to offer hoseless computers, will be bringing out a three-mix model for technical diving that will use different transmitters for each of three different gases.

Suunto, says Jim Clymer, uses a proprietary analog signal (similar to a heart rate monitor), which is less complex than competitors’ digital technology. Clymer says this signal will be restored quickly if it’s interrupted.

Suunto, by the way, is the leading U.S. seller of dive computers according to Leisure Trends, which studies retail sell-through at participating independent dive shops. For the 12 months ending last June, Suunto accounted for 46% of all units sold. Oceanic was second with a 25% market share, and Uwatec came in third at 12%.

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