Still confused about lift
- Thread starter mi000ke
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halocline
Contributor
So I guess the "idiot" in question here actually could get to the surface without your extra lift.
Your profile says that you are in instructor, and yet you seem to be advocating a rescue technique (using your own BC to lift another diver) that I have NEVER heard of being taught by any of the major agencies, in fact as far as I know they teach the opposite.
Further, you say that personally you have used extra lift to rescue "SEVERAL" (your caps) divers who supposedly otherwise could not get to the surface, and yet one almost never hears about divers dying because they were 1 )overweighted AND 2) had a BC failure AND 3) could not ditch weight. In fact, I don't know if I've ever heard of such a scenario actually occurring here on planet earth. I'm sure it has, but if it were a epidemic I'm sure we'd all be reading about it on this forum.
If you as a 'dive professional' want to dive with excess lift so you can rescue divers using a technique not sanctioned by any of the teaching agencies, fine. But advising a new (or newish) diver to do the same is not very professional, is it?
cool_hardware52
Contributor
I could not agree more.
Advocating using your BC as a lift bag is not recognized by any training agency.
This should however come as no surprise. DumpsterDiver has in the past advocated diving to 200 fsw on a single tank of *air* and claims to have taken his child on deco dives.
I have to ask where are the Scubaboard moderators?
Tobin
dumpsterDiver
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Wow you sound angry. I never said I have used extra lift to rescue several people.. Sorry didn't say that.
If a diver's BC fails and they have no ditchable lead, what do the training agencies say to do? it has been many years since I have been involved in teaching people to dive as a professional... so what do they say to do? Do they say to use the victim's failed BC? Or do they say that you should exert yourself and manhandle the situation and KICK them up like Tobin references?
If you have sufficient skills, (which i think is applicable to myself) then i would rather use my BC to provide the necessary lift in order to make me and the victim that I am clutching, neutral or near neutral so that I can get us to the surface with the minimal level of physical exertion. I'm not as strong as I once was, so I would rather try to finesse the ascent and know that I have reserve capacity in my BC.
I used to dive as crew on a liveaboard where the crew dove with no BC's.. just a backpack and a 80 cu-ft tank. I could do that myself while solo, no problem. But I told them I would NOT do it with customers. If a customer got in trouble I absolutely wanted to be wearing a BC so that I can provide some buoyancy to the victim in an emergency.
edit: And Tobin agrees? He can't read what I wrote either? You guys are starting to crack me up... Call the moderators!!
cool_hardware52
Contributor
Don't flatter yourself.
It's not anger.
It's frustration that dangerous behavior is being advocated.
That serves no one.
Tobin
halocline
Contributor
It's easy to misinterpret the tone of posts; I'm not angry at all. I just think your advocacy of choosing a BC with extra lift so that you can use that lift to 'rescue' a diver who for some unknown reason can't get to the surface is irresponsible, especially considering you are apparently an instructor for an agency that mandates a different rescue technique.
However, you are right that I mis-quoted you about "rescuing several divers" this way. You said: "I've repeated now SEVERAL times that the excess bouyancy is useful to rescue an over weighted diver who has a bc failure and has no ditchable lead."
So, have you ever rescued a diver using your own BC as lift to carry him/her to the surface? Aside from the example in which you said the diver went to the surface by himself, apparently not needing your 'rescue'?
dumpsterDiver
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I've used a lot of Buoyancy at the surface when grabbing panicked divers and hauling them a short distance to the back of the boat. I've done only one true underwater rescue on a female customer who spit her reg and refused mine at 60 feet. I just grabbed her and hauled ass up. I don' think I even though of using a BC. When we reached the surface, I pressed her inflator, but her tank was off and it didn't work.
So I've never used the excess lift capacity to rescue a diver underwater that I can recall.
ams511
Contributor
The Halcyon Eclipse is used for most of my South Florida diving. People seem to forget that the ocean water does get cold in South Florida and exposure protection can run from a skin in summer to a 5 mil (and more if you get cold) in winter. The DSS 20 was purchased new from eBay at a good price. I purchased this primarily for travel, because I don't want to risk my expensive Eclipse being lost or stolen. I used it on a few trips and in summer in Miami. The UTD 37 was purchased for sidemount doubles. I played around with it for doubles but used it more for backmount singles. The UDT does have bands that you can attach to the waste of the harness to restrict inflation. It is also a bladderless design so there are no folds inside which may trap air.
For most of the diving I do the Halcyon would be fine. As mentioned the DSS was purchased because of fear of loss/theft. The Halcyon packs quite small and would be fine for travel especially if you use a 2 piece STA. The UTD could also be used for travel, cold water diving and side mount so it probably is the most adaptable out of the trio.
---------- Post added May 17th, 2015 at 10:47 PM ----------
Many dive agencies recommend this approach to weighting. However, problems could arise when trying to hold a safety stop. If you are neutral at the start of the dive then by the end of the dive you are light by the amount of gas expended, 5-6 lbs. If you suit loses that amount of buoyancy or more at 15 feet then you can hold the stop. If it doesn't lose that amount then it will be difficult to hold a stop. While a 5-7 mil suit may lose that much buoyancy at 15 feet, I am not sure a 3/2 mil would.
From what I remember from the DIR fundies book they recommend weighting at 15 ft. with an empty (500 psi) tank.
eelnoraa
Contributor
While I don't agree having extra lift for rescue others, I however think 17lb or 20lb wing is very small. In warm water minimal suit, full AL80, you are 6lb negative by the gas only. You have 11lb of lift total for staying above water. Now the part of the wing above water provide no lift and the stuff above water is heavier than if they are underwater. You ended up having 7-8 lb of lift for floating above water. I found my head isn't comfortably above water with DSS17. I just don't understand what is the gain of having a 17lb wing vs a 30lb where drag, venting are practically the same.
ams511
Contributor
While I agree with you that a 20 lb or less wing is very small, your analysis is not quite correct. It is not the weight of the gas that matters but the buoyancy of the cylinder. A 80 CF cylinder is roughly 2 lbs negative, however when you add the plate, regs, D-rings, etc. you are at 6 lbs or more.
The same people that recommend the smallest wing are also the ones that say a BC is not a safety device and if you want to stay out of the water then just lean back and float.
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