Back Inflation BCs

[TwoTanks]

I dive two rigs, A Zeagle Ranger, and an OMS backplate w doubles. The oms with the doubles never pushes me forward, the zeagle ranger will sometimes, when I don't have a pony bottle on my back.
Be aware that it only happens when stationary at the surface and it is not a problem to resist. for a surface swim I lay on my back and kick away from shore, this is actually easier than a surface swim in a jacket style bc.
Back inflation BCs feel a lot different that jacket style BCs, but I like them better.
I wouldn’t spend too much time worrying about how you float when you’re unconscious.

 

[Jason B]

When diving shallow in hot weather I dive a ... 2 piece 7 mil wet suit.

7mil for hot weather?
Is this because you have a 7 mil wetsuit from dives gone by or do you prefer the 7mil in warm water for a particular reason? Serious question.

 

[wolf eel]

OK for everybody who dives a Halcyon BCD you must understand you are diving with loads of weight in the back plate. Sorry but for the rest of us it is not so. Which I am going to put another foot in and say it is a good idea they have (less weight needed to carry).

I am not going to get into what brand we are going to use but it is heaver in the back.

My point of including the fact that I dive with weights on my tank is to show I have adjusted my weight to compansate for forward motion. If my back plate weighed 6lb's it would pull me more backwards. I have put 5 pounds on the bottom of my tank. But if I did not it would push me forward. How can it not it only inflates behind me. there is NO lift from the front. I do not understand. :help_2:

Steel tanks again weigh more and again if you have weight on the back lets say 6lbs then you would have 12lbs more then useing AL tanks. So yes it is going to pull you backwards. I bet however that you still have to give it that motion. :diver:

As for the suit when I am working deeper then 130+ I am in a drysuit with loads of warm cloths. When I am not working and working with a class I am in a wet suit better for me to deal with people. 7mil two piece. And I am very warm. 47 to 58 degrees.

But as for BCD I will only use a back inflated BCD as it operates better for my application. :butnhome:

Cheers
Foaming at the mouth

 

[Firefyter]

I dive a Zeagle Escape, with an AL100 tank, and it doesn't seem to matter about the wetsuit. I've dove 3mm, 2pc. 7mm farmer john, and a 7mm steamer. This BC has NEVER put me face down, no matter what suit I'm wearing. I wear all my weight in the integrated packets, and it ranges from 6lb. with the 3mm up to 16 with the 2pc. 7mm. You can assume all you want, but these are the facts in my case. I would advise anyone to try it before they believe all the hype, and THEN make up your own mind.

 

[MikeFerrara]

7mil for hot weather?
Is this because you have a 7 mil wetsuit from dives gone by or do you prefer the 7mil in warm water for a particular reason? Serious question.

The 7 mil is because the water is never warm even though the air might be.

If I'm only diving shallow where suit compression won't cause me to freeze and it's very warm outside I'll sometimes opt for the wet suit over the dry suit.

 

[MikeFerrara]

OK for everybody who dives a Halcyon BCD you must understand you are diving with loads of weight in the back plate. Sorry but for the rest of us it is not so. Which I am going to put another foot in and say it is a good idea they have (less weight needed to carry).

I am not going to get into what brand we are going to use but it is heaver in the back.

My point of including the fact that I dive with weights on my tank is to show I have adjusted my weight to compansate for forward motion. If my back plate weighed 6lb's it would pull me more backwards. I have put 5 pounds on the bottom of my tank. But if I did not it would push me forward. How can it not it only inflates behind me. there is NO lift from the front. I do not understand. :help_2:

Steel tanks again weigh more and again if you have weight on the back lets say 6lbs then you would have 12lbs more then useing AL tanks. So yes it is going to pull you backwards. I bet however that you still have to give it that motion. :diver:

As for the suit when I am working deeper then 130+ I am in a drysuit with loads of warm cloths. When I am not working and working with a class I am in a wet suit better for me to deal with people. 7mil two piece. And I am very warm. 47 to 58 degrees.

But as for BCD I will only use a back inflated BCD as it operates better for my application. :butnhome:

Cheers
Foaming at the mouth

It seems to me that we're missing the point a little here.

The reason that a good wing is made to wrap around the tank is because that's where a significant percentage of the weight is expected to be. That means using steel tanks when wearing heavy exposure protection.

Think about it. While al tanks are cheap and light which is great for a rental oporation in the tropics it sure isn't so good to wear a tank that can swing to a couple pounde pos buoyant and have to carry that much more weight on a belt or in pockets.

this is one of the reasons that around here we see so many divers with severe head up trim. all the weight is around their belly so when their suit compresses and they inflate the bc a little their top half gets jacked up and thir bottom gets dragged down. Of course when the same diver wears a back inflate bc, light tank and all that weight on their belly they're pushed forward at the surface. We need the weight and the buoyancy in the same place.

In my case I use a al tank when I dive a single because that's what I have but I use a plate. When I use a wet suit there's also a couple pounds threaded on a tank band to get some of it off my belly and up where I need it...FOR TRIM when the suit compresses. It just so happens that it probably helps at the surface also. You folks are using and complaing that something doesn't work when it isn't designed to work.

On the other hand a near neutral tank, jacket bc and a bunch of weight on your belly feels good at the surface because the tank isn't doing much of anything and the weight is below the bc. it just so happens that it's also why most of you cold water divers who are configured this way are standing up at depth also.

The whole thing is messed up and that's what I meant earlier when I refered to ill conceived bc's.

Weight and balance 101...if the center of gravity and the center of buoyancy are in the same place you can place yourself in and maintain (without work) any position you want either at depth or at the surface. Thats one of the reasons we use steel tanks and plates and we get the trim and stability we want at depth and at the surface.

 

[ScubaFishee]

I dive a DiveRite TransPac II with Trek Wings. When I first started using it, it DID push my head forward when at the surface. And I didn't like that one bit.

It pushed me forward regardless of whether I had an AL 80 or LP steel 80, though it did push forward with slightly less force when I used the steel tank.

I was taught to counter the forward push by either (a) placing a weight on the back tank strap, or (b) using trim weights attached to the sides of the tank bands.

Admittedly, this worked, and it worked regardless of which tank I used.

With the problem compensated for, but not really solved, and being as stubborn as I am, I figured there had to be a better way.

Through experimentation, I came to the same conclusion that MikeFerrara states in his "Weight and balance 101."

<snip>
Weight and balance 101...if the center of gravity and the center of buoyancy are in the same place you can place yourself in and maintain (without work) any position you want either at depth or at the surface.

I found that when I mounted my wing two inches lower on the harness, it moved my greatest source buoyancy (wing) closer to my greatest source of gravity (weightbelt). The two forces counter balanced.

No more forward push.

Now, I can remain comfortably in any position I want, whether at the surface or underwater. For me, this works whether I use a steel or alumium tank, whether I'm wearing a 7mm, 3mm, or 1mm, and in both fresh and salt water.

Sometimes when I dive locally, I still like to wear my trim weights on the lower tank strap, but that's because I can carry the extra weight more comfortably on my back than on my waist. Not to mention it makes hauling my weightbelt around much easier.

But, when I don't feel like attaching them, or when I travel to dive destinations by plane, the trim weights stay home. They no longer play a part in the face plant scenerio.

When not using the trim weights, just I place the equivalent amount in the TP II weight pockets (located slightly forward just above my waist).

I can only speak for myself and this is what I have found that works for me. I just thought I'd share. I can't argue about what does or does not work for anyone else.

But, if the offer for a free dive trip to demonstrate this is still open, let me know and I'll go back my bags. And I'll even leave the trim weights at home.

 

[MikeFerrara]

I found that when I mounted my wing two inches lower on the harness, it moved my greatest source buoyancy (wing) closer to my greatest source of gravity (weightbelt). The two forces counter balanced.

Interesting. I can't say that I've tried moving the wing for this reason although I do know that using a crotch strap or other means of holding the rig in place can help.

Something to think about.

 

[mech]

So I'm thinking that it's safe to say poorly fit and poorly trimmed out gear is the culprit of this face plant phenomenon.

 

[ScubaFishee]

Interesting. I can't say that I've tried moving the wing for this reason although I do know that using a crotch strap or other means of holding the rig in place can help.

Something to think about.

Yeah, before the adjustment, I could really feel the tug between the wing pulling up and weightbelt pulling down. (Still can a little, but only if I overinflate at the surface. So I don't do that anymore. )

Fortunately for me, natural curves at the waistline keep the waiststrap from riding up. Otherwise, I might need a crotch strap.

The light bulb came on for me after I saw photos taken of me and some dive buddies in water at the surface. I'm 5 ft. 2 in. They are both 6 ft. plus. In all the pictures, their wings are mostly underwater, where as the top of mine was near my head.

We all used the same bolt holes, which positioned the bottom of our wings and harness in the same place. But they have longer back-waist measurements and larger harnesses. Mine is x-small and the wing itself is longer than my back waist length.

Any push from theirs would be against the body. The push on mine was strongest against my neck and upper shoulders, the area of least resistance. I had problems with my face being pushed in the water. They didn't.

I just knew I had to get that air cell lower on my body somehow.

Moving the wing down isn't in the manual anywhere. But as they say, necessity is the mother of invention.

Now, if someone will just start making gear sized for the shorter adult... oh well. :05: