Partially Closed Valve Causes Breathing Difficulty
A diver with a partially closed tank valve has difficulty breathing at depth and has to share his buddy's air during ascent using a secondary regulator.
>A group of divers was participating in a boat dive at a depth of 70 fsw (21.3 msw). The water temperature was 46°F (8°C) with 40 ft (12 m) of visibility. About 10 minutes into the dive, a male member of the group, who was separated by approximately 10 ft (3 m) from his buddy, signaled that he had a problem. It was not clear if he was out of air or low on air based on his signals. Two divers swam over to assist him.
>The diver indicated a problem with his tank valve. His pressure gauge showed he was not low on air. The tank valve was checked and appeared fully open, but the diver still could not breathe out of it. His buddy joined the small group and began sharing air using his alternate second stage. The remaining divers stayed close by for a few minutes to ensure the pair was calm and could ascend in a controlled manner. The remaining divers were able to finish the dive.
>Back on board the boat, the diver with the problem admitted having difficulty fully opening the tank valve when gearing up. He donned his scuba unit without knowing whether the tank valve was fully open. He also chose not to tell his buddy. Most likely the partially open valve would not allow adequate flow into the first stage as the ambient pressure increased.
>This situation presents multiple problems. It is the responsibility of each diver to ensure that his equipment is in proper working order prior to each dive. This diver knew that his tank valve was problematic and chose to dive despite the problem. This could have resulted in a catastrophic outcome. Attempting to dive with suspect equipment is never prudent. Another poor choice was not informing his buddy of the problem. Diving with less than efficient equipment does affect the individual(s) with you as they need to respond in an emergency.
>Our choices clearly do not affect just us as individuals. Had this diver discussed the situation with his buddy, together they may have decided not to dive. At the very least, his buddy might have remained in closer proximity to him in anticipation of a potential complication. Being within visual proximity with your buddy can still allow too much distance between you in the event of an emergency. Divers other than his buddy were the first to reach him.
>In fairness, the responding divers may have simply been faster swimmers, but it is imperative to be within immediate reach of your buddy. Bear in mind that buddy separation was reported in approximately 40 percent of dive fatalities. Be diligent in inspecting and maintaining all your equipment. If any equipment is not functioning at 100 lpercent, it is in our best interest not to dive. At least involve your buddy in the decision process. It is very tempting to increase the distance between you and your buddy on dives that offer favorable visibility, but think of how quickly a situation can deteriorate from a simple problem to an emergency. Maintaining a close physical proximity can offer the best response time and can potentially prevent a problem from escalating.
— Marty McCafferty, EMT-P, DMT, EMD-A