You know, there are really two things about overhead environments that everyone should keep in mind. One is that, once you get in, you have to get out. And the other is that, while you are there, you have to solve any problems you have where you are.
One of the essential ideas of recreational diving is that the surface is always an option. Feel overwhelmed or frightened, or unable to solve a problem? Ascend (hopefully under control and breathing the entire time) and you should be able to make the great gas tank in the sky. In any overhead environment, no matter how trivial, that is not possible. If you're swimming through the big rock arch at Landing Cove on Anacapa (which is about 20 feet long) the period of time that you have to keep your act together is pretty brief; if you are in the Ginnie Ballroom, it's considerably longer -- and that challenge has resulted in at least one death. The Cathedrals off Lanai are spacious rooms with lots of light, a coarse sand bottom, and multiple exits. But a panicked diver in that environment would still be in terrible danger.
Swimming through the wreck of the Rhone in the BVI is fun, and you would have to work very hard to be unable to see your exit. That is not true of all wrecks or caverns, and some silt is truly nasty. Even a very open space can be terrifying, if there is more than one "exit", and some don't lead to open water. There is, somewhere, a chilling account of someone who swam into a huge, open rent in the side of a wreck to look at or for some pots or bottles -- and reduced the viz, and couldn't find his way to the huge opening through which he had come, but instead found a doorway that led deeper into the wreck. He was at the point of writing a goodbye letter to his family, when he gathered some more gumption and found his way out.
Some overheads are pretty benign. But it may not fall within the capacity of an OW diver to evaluate and accurately assess any particular overhead for its particular hazards.
One of the essential ideas of recreational diving is that the surface is always an option. Feel overwhelmed or frightened, or unable to solve a problem? Ascend (hopefully under control and breathing the entire time) and you should be able to make the great gas tank in the sky. In any overhead environment, no matter how trivial, that is not possible. If you're swimming through the big rock arch at Landing Cove on Anacapa (which is about 20 feet long) the period of time that you have to keep your act together is pretty brief; if you are in the Ginnie Ballroom, it's considerably longer -- and that challenge has resulted in at least one death. The Cathedrals off Lanai are spacious rooms with lots of light, a coarse sand bottom, and multiple exits. But a panicked diver in that environment would still be in terrible danger.
Swimming through the wreck of the Rhone in the BVI is fun, and you would have to work very hard to be unable to see your exit. That is not true of all wrecks or caverns, and some silt is truly nasty. Even a very open space can be terrifying, if there is more than one "exit", and some don't lead to open water. There is, somewhere, a chilling account of someone who swam into a huge, open rent in the side of a wreck to look at or for some pots or bottles -- and reduced the viz, and couldn't find his way to the huge opening through which he had come, but instead found a doorway that led deeper into the wreck. He was at the point of writing a goodbye letter to his family, when he gathered some more gumption and found his way out.
Some overheads are pretty benign. But it may not fall within the capacity of an OW diver to evaluate and accurately assess any particular overhead for its particular hazards.
