The final in a series of three excerpts from Simon’s new book: Scuba Exceptional…
Ian back-rolled into the water and dropped down fast to 20m, at which point he reached for his inflator to inject some air into his BCD to halt his descent. However, when he pressed the inflator button, all he did was inject a stream of air directly into the ocean. He looked down and, to his surprise, saw that his inflator mechanism was connected only to the low-pressure inflator hose. His corrugated BCD hose was nowhere to be seen.
He continued to drop. He tried finning up to arrest his descent but this just slowed him down. He was still descending with no means of correcting his negative buoyancy. He was using a wing and harness BCD with a 7kg stainless steel backplate and had no free weights to ditch. Luckily, his diving companions were close by and came to his assistance. They got him back to the surface, so he lived to dive another day.
Ian had come up with the idea of wearing a heavy backplate with his BCD because he didn’t like wearing a weightbelt or weight pockets. He always worried that a belt might slip over his belly and fall off, causing him to shoot to the surface. And weight pockets always made his legs drop, giving him a seahorse-like posture.
Ian had never considered that his BCD might fail during a dive. All BCDs have multiple failure points. The wing can tear, dump valves can shear off and inflators can fail in multiple ways. Every diver should always make sure they can reach the surface and stay afloat once they get there without the assistance of their BCD. This is usually achieved by dropping some or all of their weights. All Ian’s weight was in his backplate. There was nothing he could do to make himself positively buoyant, except remove his equipment entirely, which, at depth, might have been disastrous.
The problem that had caused Ian’s BCD to fail on this occasion was that his corrugated hose was only connected to the BCD pump mechanism by a single cable tie and this cable tie had broken and come off. Cable ties are notorious failure points, which is why all good BCD systems have TWO cable ties or a permanent heavy-duty screw fitting at each end of the corrugated hose.
Good BCDs also have some sort of permanently fixed bridging or wrapping device connecting the corrugated and inflator hoses. This device is there so that if the corrugated hose comes off the pump, it will stay in place next to the inflator hose. The diver can then reattach it to the pump and hold it in place manually while they inflate the BCD. Ian’s BCD had no such connector, so his corrugated hose just floated off behind his back. He might have been able to reach it but he was so bewildered, he didn’t even think of that.
Be aware of the potential failure points in every item of your equipment and make sure you know what to do to survive when a failure point fails.
This piece is adapted from a chapter in Simon Pridmore’s new book Scuba Exceptional – Become the Best Diver You Can Be available now from Amazon, iTunes, Kobo and other online bookstores.