Hover problems

[24940]

No i was diving a jacket style bc.
By a back inflate do you mean wing style?

I'm referring to a BC which has the bladder in the back. A wing would be an example of back inflate, but many jackets are also back inflate, the Black Diamond, for example.

Three things can affect your trim, AFAIK... Ballast, buoyancy and energy.

It sounds like your ballast is balanced, so I'm guessing it has to do with buoyancy. If the bladder tacos a bit, it can isolate the left from the right and allow more air on one side than the other. This results in the side with more air providing more lift than the other side and you roll.

 

[BreatheDeep]

The bc's i have used are true jacket styles,the bladder wrapped around the sides of me as well as the back.Could this style of bc allow unequal air amounts?
Do you think i could get on with a bp/w at this stage inmy diving?

 

[24940]

The bc's i have used are true jacket styles,the bladder wrapped around the sides of me as well as the back.Could this style of bc allow unequal air amounts?

Not too likely, but I suppose it's possible.

Do you think i could get on with a bp/w at this stage inmy diving?

Absolutely.

 

[willembad]

Hi,

Welcome - there is a wealth of information here - just make sure you think about all the responses your getting, including this one, and think about what makes sense and what does not.

Firstly, it is hard to tell what's going wrong without seeing you in the water, but most of the trim problems I have seen started with people diving way overweighted. If I think back to my beginning dives - where I thought I had my weighting sorted out - and the weight I dive now it is hard to believe how little I really need versus what I thought I needed. Try just enough to sink you in whatever suit you dive in and NO air in the bc. You have nothing to lose but a few minutes of tinkering and I bet you will be surprised at the results.

Secondly, I would strongly recommend that you NOT go out and buy a bc. Find some local divers with experience (not neccesarily instructors) and dive with them so they can have a look at your trim. Talk about all the possibilities before you decide on what you need. With a little homework you could easily purchase a bc that would last years and cover many different paths your diving may take you in the future. Think simple, adjustable, adaptable.

Willem

 

[rstofer]

The bc's i have used are true jacket styles,the bladder wrapped around the sides of me as well as the back.Could this style of bc allow unequal air amounts?
Do you think i could get on with a bp/w at this stage inmy diving?

There is no problem converting to a BP/W but be sure you are not trying to apply an equipment solution to a skills problem. By that I mean you need to repeat the experience and find the cause. A loose BC will do it. A tank not staying vertical in the BC will do it. Unequal weight distribution will do it. There are probably other things that I'm not thinking of at the moment. But it's something!

Solve the problem before you move on. A BP/W brings its' own problems. No pockets and no integrated weights unless you mount weight pockets to the belt. Personally, I don't like integrated weights so I use a DUI Weight & Trim Classic Harness with my Deep Sea Supply BP/W. I miss the pockets. The wing may not float you as high as a jacket and you may find it more difficult to remain perfectly vertical when the wing is overinflated.

You need to consider how much of your ballast will be ditchable before you decide whether to use an aluminum or stainless steel backplate. There is also the possibility of a plastic backplate. In any event, you want some ditchable weight. Your choice of tanks will also affect this decision. If you only need a few pounds of weight, you probably don't want a highly negative tank and a stainless backplate.

Remember, if you are rescued, one of the first steps is to establish positive buoyancy by ditching the weightbelt (or weights). If you don't have any, your rescuer will not be able to do this.

Richard

 

[TSandM]

If the BC is a little off center, more gas will go to one side of it (looking for the highest point). Then you are more buoyant on that side, and will tend to rise there and fall on the other side. As you rotate, MORE gas moves to the higher side, thus worsening the problem.

A loose BC is a PITA.

There IS a certain amount of learning to balance the tank and gear on your back, like learning to ride a bicycle, only upside-down. You almost never hear anyone talk about it, but you do need to learn to keep your body relaxed and flat and even, because body parts affect your balance, too. But by far and away the biggest piece of inertia you have is your tank, and having it stably in the center of your back makes life MUCH easier.

 

[String]

The hover skill is purely to test neutral buoyancy not trim - you dont have to stay upright in it.
In fact, its a bit artificial - you dont WANT to be upright in the water anyway so you really dont want to work on getting that way.

 

[mood]

The hover skill is purely to test neutral buoyancy not trim - you dont have to stay upright in it.
In fact, its a bit artificial - you dont WANT to be upright in the water anyway so you really dont want to work on getting that way.

Yeah but he mentioned that he cant get horizontal.. more of a sideways horizontal which wont do him any good.

To the OP, im sure everything there has been said. My thoughts are as follows:
Try another BC with the same belt and same weight placement. If that fixes your problem, then the BC is whats screwing you. If not, try adjusting the weights to counter the left drag by placing a bit more on your right side. If your using 3lbs, try breaking it into a 2lb + 1lb.

Good Luck,
Moh'd

 

[Slonda828]

Breathdeep,

Lots of good things have already been mentioned. I would add that if you let yourself go slack in the water (as in relax control of your muscles that are holding you tank up), and you rotate to one side (which you mentioned) instead face up, you are off kilter somehow (which you already know).

There are really two opposing forces working here, the gas in your BC, which is pulling up, and the weights on your body, which are pulling down. In addition to making sure that your BC is snug to prevent air shifting (which TSandM mentioned) and distributing your weights evenly (which someone else mentioned) I would add that your weights should be as close to your gas as possible. This is ( one of the reasons) why the ubiquitous backplate and wings affords good trim, because your ballast and gas are close to one another. Try shifting your weights closer to your bladder if you can, or adding some of your weights to the tank band. This should help keep you trimmed out. Furthermore, once noting which side you rotate to when you go slack, move a half pound (if you have half pound weights, I do) to the opposite side until you only go face up when you relax.

I would also add that if you weight yourself properly and distribute weight correctly, you can dive in almost ANY BC regardless of type provided it fits you, and stay in trim.

I hope this isn't too pedantic, and hopefully this helps.

 

[redrover]

I had the opportunity to test a BC tooted to be very tank stable but would list to one side or other. Not a shift, but thunk, did not seem at all stable to me. With the rep there, couldn’t get me to stop listing. I wondered how anyone could stand it.


Something I like about integrated weight is it does not shift. A weight belt slid all over me. (Could have been snugger but that was very uncomfortable in it’s self.)