Reported Story

After the third dive of the morning, a buddy team surfaced due to a second-stage free-flow failure. During the surface interval, I noted that the buddy team and several other divers were attempting to correct the problem. It was determined that the regulator had a mechanical failure that could not be corrected. A diver in the group offered the effected diver a spare regulator setup for use during the rest of the trip.

Later I overheard a discussion about using the computer attached to the borrowed setup; someone said that "it is the same kind of computer so there is no problem with operation."

I immediately advised them against using the new computer because it could not account for the previous two dives to 80-plus feet the diver had already made. None of the team members had thought of that problem because they were too focused on getting a functioning regulator setup for the effected diver.

I suggested the diver use the computer from his previous dives; he did, and the group continued without any problems for the remainder of the dive trip. That diver avoided a possible episode of decompression sickness.


This was good advice from the third diver. A dive computer is a personal device and is only as good as its record of all the diver's dives separated by surface intervals shorter than 24 hours.

Divers should never start another dive on the same day using a different dive computer. Additionally, experienced and knowledgeable bystanders should not hesitate to provide proper advice; it may be lifesaving.

To learn more, read "Your Computer Fails: Now What?" by Robert N. Rossier.

— Dr. Petar J. Denoble