I had written: >They could not float just below the surface. Nothing floats like that; To which Stan and Robin Kurowski responded: >Paul, haven't you ever "hung" at 15 ft. for a safety stop after diving; I'm >sure Cindy has. Balance weight and buoyancy (displacement?) and you can >float at any depth. Being former cave divers, Cindy and I are extremely familiar with buoyancy control. Either one of us can hang three inches off a clay bottom without a flutter of a fin or hand to stir up the silt, and at the same time also control body attitude with buoyancy. (We hang slightly head down to help keep the fins out of the silt.) The key word here is "control." That implies that you actively control your buoyancy to maintain position. Try this experiment. All you need is a soda bottle. Turn it upside down and full of air. Bring it down with you and watch the air compress. At one particular point, it will have neutral buoyancy. If you can find that point perfectly and let go of the bottle, it will hang there momentarily; but then will either rise or fall, depending upon the very small amount of error you made in placing it on one side of that neutral point or the other. Even if you were to find it perfectly, with absolutely zero error, the small pressure changes caused by the waves will rock the boat; and either send the bottle to the surface or to the bottom with no further input from you. To hang at neutral buoyancy requires active intelligent control, if the object in question has any air in it at all. You asked about hanging for a safety stop. Part of the reason that decompression diving in open water is considered so dangerous is because hanging at exactly the right depth is so difficult, or at least it is so very easy to make a mistake and drift from the desired depth below the surface. This is why I said that it was impossible for a container to float just under the surface. It has no intelligence to control its buoyancy. Perhaps this is a small point, since they can float 99.99 percent below the surface. In that case, the waves can wash over the top and make it very difficult to see. Boatless, but building M/V Doulos http://www.anyboat.com/kruse1.htm Paul Kruse plkruse@iu.net Port Canaveral, FL, USA

     Myles

Paul, I will explain why I agree with you on the other post. But, on this one, I agree again. A storage container doesn't have the luxury of a BC and the brain when to use it. So only the law of physics will determine where it is positioned when your boat hits it. Then it is to late to argue about it. The whole point was that these storage containers can be a threat, so be careful. However, there are many hazards that pose a danger, so be wary of all and be prepared to managed the situation if you have an encounter with one. Myles