Computers in scuba diving can sometimes malfunction. In case of a computer failure, divers are advised to abort the dive immediately and make a safety stop at 15 ft for three minutes. After surfacing, write a dive profile for the day.

There are certain things that strike fear in our hearts: a 60 Minutes film crew at our business doorstep and dive computer screens that go blank.

A technology failure at 60 feet – what do you do?

Whether the battery died or the case has leaked, without the computer’s input and record keeping you must take manual control of your dive plan.

Immediate Action:

  1. Look at your depth gauge, watch and submersible pressure gauge and memorize their readings.
  2. Abort your dive and begin ascending at a normal rate.
  3. Make a safety stop at 15 feet for 3 minutes, then proceed to the surface.
  4. Once on the surface, write down the data you memorized at depth when the computer failed.

Planning Your Next Dive:

When you are safely out of the water, you may want to make another dive. Can you do this safely? The answer is not a simple yes or no. It depends upon your dive profile and if you kept manual data to back up the failed computer’s record keeping.

If you have not kept complete manual records, the training agencies recommend the most conservative course of action, which is to wait 24 hours before making another dive.

If you have kept manual records of your dives within the past 24 hours, use the standard dive tables and compute your current group. Based upon your previous depths, dive times and surface intervals, determine whether you have sufficient bottom time to make the desired dive.

Since computers operate on multi-level dive profiles, they tend to allow more time underwater than the tables. Easy to read tables based upon the U.S. Navy tables calculate a dive as if all of it took place at the greatest depth. When you manually calculate your dive profile using the navy tables you may find there is not sufficient depth/time available to make a certain dive. Regardless of how disappointed you are, the most conservative, safety-minded advice is to only make a dive the navy tables calculate is within the no decompression limits.

The NAUI Open Water Instructor Guide lesson on dive computers summarizes what most of the instructional agencies teach. The basics are:

1) Each diver should have a separate computer.

2) Students should be trained in the proper operation of dive computers (this will lessen failures from operator error).

3) If a computer fails, terminate the dive immediately.

4) Wait 24 hours to dive.

5) If backup data is available, revert to the tables and only continue diving if allowed by the tables.

6) Stop at 15 feet for 3 minutes as a safety precaution.

When your computer fails it can be very tempting to rationalize that your dive profile was “just like” some other diver’s and use the readings on his/her computer. Do not use another diver’s computer data!

Remember how hard it is to keep your buddy right next to you? Only a diver who was exactly next to you at all times could have a computer with the same data. This is almost impossible. Other divers may have similar profiles but when your health is at stake that is not good enough. No dive is worth the risk of getting bent.

Depending upon the nature of the failure, it can be an easy fix or the unit may need to be returned to the manufacturer for repair.

You may just need a new battery. Some computers allow you to remove a battery and insert a new one without losing data. Other batteries should only be changed when there is 24 hours between dives. Buy your batteries at a store that has a high inventory turnover to ensure freshness. Keep batteries in a cool place – refrigerators are ideal. When traveling abroad, bring several batteries.

Your computer battery compartment may seal with an O-ring. If so, it is advisable to carry a spare O-ring and lubricant. A single grain of sand can make an O-ring leak, so meticulous attention to detail helps prevent leakage.

Some practical advice from underwater photographers, who tend to flood electronic equipment, includes pouring out the sea water and rinsing the equipment with freshwater to try and minimize corrosion. Thoroughly dry the equipment. If you are in a tropical climate, don’t store it in a resealable plastic bag – that is equivalent to placing it in a mini-sauna!

Summary

Computers add to the enjoyment and safety of scuba diving. They are wonderful tools to enhance your underwater experience. However, they do suffer from occasional operator error and electronic failure. If your computer fails, abort the dive immediately and stop for 3 minutes at 15 feet on the way to the surface. If you cannot accurately reconstruct your day’s dive profile, cease diving for 24 hours. If you have kept manual data, use the U.S. Navy tables to calculate any future dive plans. Only use data from your computer and gauges when calculating your status on the tables or making an additional dive within a 24 hour period.

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