空氣不足－還有足夠的空間可以呼吸

這是怎麼發生的？

At first, Richard was bewildered. Surely, his valve must have been open when he had started the dive, or he wouldn’t have had air to breathe during the first few minutes. He dismissed the possibility that Florence might have crept up behind him and closed his valve as a prank. She would never do that.

然後他就想，或許是自己的身體出了問題。 調節器. But it had worked perfectly at the start of the dive, and again when he had switched back to it after opening the valve.

It was only much later that he deduced what must have happened. When he had put his gear together on the boat, he was sure he had fully opened his cylinder-valve, as was his usual practice. However, on that day there was a temporary and relatively inexperienced crew-member on board.

This person had helped Richard, Florence and the other divers into their gear, and Richard had noticed him turning other divers’ air on.

Unaware that Richard had already turned his air on, the helpful crew-member had mistakenly closed the valve, thinking he was opening it. He had then twisted it back a quarter of a turn, re-opening it slightly. This meant that when Richard entered the water and began to descend, he could still breathe properly.

It was only when he went deeper that he began to have a problem. The only-slightly-open valve could not supply the quantity of air (usually 9 bar or so above ambient pressure) required to keep the regulator working.

Had the crew-member closed the valve completely and not turned the handle back a little, Richard would have found the problem while still in the shallows, possibly while on the surface waiting to descend, as he used up the small supply of air in his reg hoses. With the valve slightly open, he lost no air until he was at depth.

When most people learn to dive, they are told that, when they open the cylinder valve, they should turn it all the way and then twist it back a quarter- or a half-turn.

This advice dates back to the middle of the last century when scuba-diving was in its infancy, and it was feared that valves could get stuck or be damaged if they were left open all the way.

With today’s cylinder-valves, this is completely unnecessary. Once a valve is fully open, all you can achieve by turning the handle back is to partially close it.

There have been incidents in which divers have been so enthusiastic about turning the valve handle back that they gave themselves a similar problem to the one with which Richard had to deal.

忘記你在書中被告知的內容 訓練. Turn your valve all the way on before you put your scuba gear on. Then don’t let anyone else touch it.

有用的技巧

有兩個因素將原本可能是悲劇的故事變成了一個有用的故事：兩者都涉及技術問題。

1. Richard’s calm response, borne of good diver 訓練. Although this was not a technical dive, the instinctive technical-diving skills Richard had learned came in very handy.

2. Florence’s readiness to assist. A new diver then, she responded like a veteran. This was because she and Richard had practised air-sharing frequently. A much more experienced diver, he is a big chap and Florence is a slight lady. So he consumes air far more quickly than she does and, near the end of their dives together, often turns to her to share her air for a few minutes.

A final note: Richard’s habit of carrying a back-up analogue gauge allowed the pair to continue the dive after taking care of the emergency. Without it, he would have been blind as far as his residual air supply was concerned, and would have had to abort the dive anyway.

閱讀更多關於西蒙·普里德莫爾的內容：

水肺機密 – 成為更好的潛水員的內部指南
水肺專業人士 – 深入了解運動潛水員 技術培訓 & 運營
水肺基礎知識 – 以正確的方式開始潛水
水肺生理學 – 你認為你了解所有關於水肺潛水醫學的知識嗎？再想一想！

所有這些都可以在亞馬遜上以多種格式獲得。