A thinking dive computer

The Aladin Sport

AT A GLANCE

Instructions 85%
Activation 92%
Underwater displays 96%
Legibility 96%
Violations displays 95%
Decompression 95%
Surface displays 85%
Overall score 90%


How the Dive International test works:

Teams of ordinary divers put each item of equipment through its paces, with five divers each taking the equipment on five dives, allowing them to become completely familiar with it. All are observed during the dives, complete a questionnaire and are interviewed afterwards. The baseline criteria of the tests will ensure the testing of similar products can take place months apart and still be uniform, allowing consumers to draw direct comparisons.

Diving computers have revolutionised the way recreational divers dive. They adapt to repetitive and multi-level profiles, instantly calculate decompression obligations and provide freedom, although with a strong responsibility clause, simply unobtainable with tables.

In 1987 a small, lightweight and affordable computer arrived on the scene. Uwatec's Aladin utilised an algorithm or programme based on the leading Swiss decompression expert AA Bhulmann's dive tables.The rest, as they say, is history.

Uwatec's current computer line-up includes the Pro, which is a full decompression computer, and the Air X, which offers hoseless air integration and a mix-adjustable Air X Nitrox version. All of the current range use Uwatec's new 'smart' Bhulmann algorithm, which adjusts decompression obligations according to profile, temperature and Ð with air-integrated models Ð work rate. We tested the Aladin Sport, which is Uwatec's new 'budget' computer.

The Sport is a 'no decompression' computer by our definition. That means that it provides only limited decompression information compared to the Pro and Air X. Whereas the Pro and Air X calculate and display the total time to surface, including time spent at stage stops, which helps with gas management, the Sport only tells you that you have entered decompression and at what depth you should stop. However, this limited information is invaluable if a diver goes into unplanned decompression. The Sport calculates the decompression penalty and guides the diver through it. For unplanned decompression dives, the ability of the Sport to instantly produce numbers relieves the diver of trying to read tables with decompression rules they may have forgotten how to use while under stress, possibly suffering from narcosis and perhaps in conditions that make the tables unreadable (always assuming the diver even has tables).

The Sport uses the ZH-L8 ADT adaptive algorithm which takes into account not just time and depth, but also whether the diver made yo-yo ascents, saw-tooth profiles, or in the computer's mind, got cold. It will take time to establish whether Uwatec are on the right tracks, but it is an innovative approach and as we will see later in this report, the Aladin Sport can provide times very different to its predecessors for the same dive profiles.

To test the Aladin Sport we used a combination of subjective user-assessment and formal bench testing. Our five man test team was drawn from the Gibraltar Sub Aqua Club, a BSAC branch. Until recently the club did not allow computers on club dives, preferring instead to use RN Table 11, a reflection of the GSAC's Navy links. Two of the team owned computers (not Aladins) but could only use them as computers on private dives. For the three other testers, the Sport was the first computer they had ever used.

Instructions

Dive computers are sophisticated instruments. Computer manufacturers usually stress that they are for guidance and make recommendations that require the diver to follow certain procedures. Additionally, modern computers often have special logbook or other functions that can only be accessed using a specific drill. So we asked our test team to evaluate the 60-odd page instruction manual for ease of understanding.

Only four out of the five testers read the instructions. Their overall score was 85%.

Activation

The Aladin Sport remains 'on' at all times, though the display will be off to conserve battery life once the unit has been surfaced for a few minutes. It automatically senses, and adjusts for changes in, barometric pressure such as an ascent to altitude to lake dive. The automatic activation effectively bars a diver from entering the water with an erroneously set computer that could provide misinformation and affect safety Ð it's virtually diver-proof. Overall score: 92%

Underwater Display

We believe that it is vital that a computer display is easy to understand underwater. In an emergency a diver may not have time to analyse a confusing display. The Aladin's displays were tested under severe conditions Ð visibility and light levels were very poor and several members of the test team were slightly affected by narcosis on one dive. The Aladin uses an LCD display which retains light Ð basically a high tech version of the luminous batons on a watch.

We asked the test divers to score the display considering factors such as whether they found the information relevant or irrelevant, and presented confusingly or clearly. Their rating was 96%. Legibility One problem with computer displays can be their legibility under different lighting conditions. Some displays 'disappear' unless the computer is angled to catch the light. The Sports were used in bright and low light, with and without torches.Overall legibility scored 96%.

Violations displays

We avoided deliberately violating the computers during in-water testing, but four of the testers received 'Slow Ascent' warnings. The sport has a variable ascent rate permitting relatively fast ascents from deep water that are progressively slowed as a diver nears the surface. The divers who saw the ascent rate cautions regarded them as clear and attention-grabbing, giving them 95%.

Decompression displays

We made one planned decompression dive to assess the decompression display. For planned stage decompression diving we believe that a computer that provides total ascent time should be selected. We have no reservations about using the Sport as a back-up computer for decompression diving. On this dive our purpose was to see how easily the decompression display could be followed by divers who were unfamiliar with it. This accounts for most potential Sport users who will probably only see the decompression display as a result of unintentionally and briefly overtaking the No Stop times or making a decompression dive 'to see what it's like'. Rating 95%.

 
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