divetheworld
Registered
Although at first these look a great idea, you must be careful as to how you apply them. The purpose of the bungee should not be to streamline your wings. They will exert pressure against the inflation and cause the over pressure valve to dump well below what the ambient pressure would. They are obviously going to present a massively dangerous static lung load if you try to inflate them manually. If you tie them too tight to start with, which many do because they think it is less "drag", they will not give much lift. There have been other accidents associated with this, so I believe they are now shipped out without the bungees tied for this to be done at the dive shop or by the end user. The drag issue is in fact the opposite of that is expected. The bungee'd surface causes massive vortex shedding which increases drag. The purpose of the bungees is to be able to trim your centre of gravity by controlling the main point of buoyancy.
I do not agree with the double wing theory. The additional task loading and other associated gear complications that arise from dual inflators/wings are beyond self defeating. In keeping with the Hogarthian concept of simplicity, any additional lift requirements should be accomplished by a separate device that is capable of serving another purpose as well, why not use your drysuit? One of the biggest issues we have with double wings is that of being in the middle of another minor problem/tasks, having one of the two inflators runaway (i.e. fail and start inflating the wing) and not being able to determine which one it is. Some divers attempt to protect from this by only having one wing inflate hose and they plan to move the hose to the redundant inflator in the event of a problem - they have just compromised their so called required redundancy in that they now are not protecting from a hose blow or a first stage failure. In addition any air in that redundant wing - which was probably not noticed at the beginning of the dive when heavy, will affect the ascent as it expands - leaving the diver to drive a dry suit deflate and a wing deflate and then another wing deflate, whilst also possibly winding in a reel for the ascent.
IANTD now require that all students, attending a training course, who are using double wings have to have a check out dive with the instructor first. This dive is intended to demonstrate that the student is capable of using a double wing system.
One of the most imaginative application of the double bladder was shown to me by a very experienced diver called John Kipling, who suggested that the second bladder have its inflator removed and a dump valve fitted. The wing therefore having no inbuilt redundancy, but in the event of a catastrophic wing failure, the equipment rig can be repaired in seconds during the surface interval or perhaps at a convenient sump in a cave system.
I do not agree with the double wing theory. The additional task loading and other associated gear complications that arise from dual inflators/wings are beyond self defeating. In keeping with the Hogarthian concept of simplicity, any additional lift requirements should be accomplished by a separate device that is capable of serving another purpose as well, why not use your drysuit? One of the biggest issues we have with double wings is that of being in the middle of another minor problem/tasks, having one of the two inflators runaway (i.e. fail and start inflating the wing) and not being able to determine which one it is. Some divers attempt to protect from this by only having one wing inflate hose and they plan to move the hose to the redundant inflator in the event of a problem - they have just compromised their so called required redundancy in that they now are not protecting from a hose blow or a first stage failure. In addition any air in that redundant wing - which was probably not noticed at the beginning of the dive when heavy, will affect the ascent as it expands - leaving the diver to drive a dry suit deflate and a wing deflate and then another wing deflate, whilst also possibly winding in a reel for the ascent.
IANTD now require that all students, attending a training course, who are using double wings have to have a check out dive with the instructor first. This dive is intended to demonstrate that the student is capable of using a double wing system.
One of the most imaginative application of the double bladder was shown to me by a very experienced diver called John Kipling, who suggested that the second bladder have its inflator removed and a dump valve fitted. The wing therefore having no inbuilt redundancy, but in the event of a catastrophic wing failure, the equipment rig can be repaired in seconds during the surface interval or perhaps at a convenient sump in a cave system.
