Purpose of DIR diving style

[Carribeandiver]

Back in the day when I dove with a jacket BCD, I had gotten to where I could achieve neutral buoyancy. But, my legs were straight back, not bent at the knees. Of course, I had positive floatation fins and that may be why I could hover horizontally.
But, now after switching to a H BP/W, achieving neutral buoyancy is extremely difficult. And trim? Ahh, forget it. With my knees bent, the weight is pushed on my hips which causes my legs to drop which results in more of a 20 degree vertical then the horizontal pose I am desperately seeking. And yes, my fins are now negative which adds to the weight distribution problem.
This style of diving with bent knees and fins up is to prevent silting, right? At least, that is what I have determined to be the reason. But, isnt that counterproductive to perfect trim because of the weight distribution and load on the hips?
Doesnt that style naturally cause that 20 degree angle more than it helps the perfect horizontal position?
Almost everyone claims the BP/W promotes the horizontal position underwater but I have not found that to be true. And everyone claims the BP/W is a problem at the surface but I have not found that to be true, either. I have no problem at the surface, maybe because I am aware of where the floatation is I tend to lean back but I actually much prefer the BP/W at the surface over the jacket I used to wear.
Underwater, the BP/W seems much more difficult to dive with. At times, it pushes me on one side causing me to fight the turn over. At times, the tank seems lose (I currently use only a single) and I can feel it shifting which is weird to say the least.
I also find that the least little bit of inflation can cause a huge lift while the least bit of deflation doesnt seem to have an effect. Therefore, I am King of the yo-yo but that is another story for another time.
Any tips for a struggling beginner? I do practice but what was that I read? Practicing incorrect technique makes learning proper technique practically impossible? Ahh, therein lies my problem.
HAPPY EASTER to everyone.

 

[Colliam7]

... after switching to a H BP/W, achieving neutral buoyancy is extremely difficult. And trim? Ahh, forget it. And yes, my fins are now negative which adds to the weight distribution problem.

Underwater, the BP/W seems much more difficult to dive with. At times, it pushes me on one side causing me to fight the turn over. At times, the tank seems lose (I currently use only a single) and I can feel it shifting which is weird to say the least.
I also find that the least little bit of inflation can cause a huge lift while the least bit of deflation doesnt seem to have an effect. Any tips for a struggling beginner? I do practice but what was that I read? Practicing incorrect technique makes learning proper technique practically impossible?

Rig problem diagnosis by email is probably as ill-advised as medical diagnosis by telephone, but that probably won't stop us. . It might help some respondents if you could provide a little more information. You mention a H BP/W, so I presume you are referring to a SS BP. It sounds as though the harness may be a bit loose, but I suspect you would have mentioned that. Are you using a STA or just cam bands? What (size) wing are you using? Should we presume you are diving wet? What kind of tank (AL80, LP steel, something else)? What is you height / weight? Jet fins (you mention negative fins)? It sounds like a session with an instructor familiar with BP/W would be most useful (although you may have already done that). Providing a few of these details may not reliably lead to informed, or even useful, responses, but might help

 

[TSandM]

First off, things should be stable. If your gear is shifting around on your back, then either your harness is too loose or whatever is stabilizing the tank on the plate isn't working right. Properly assembled, a BP/W assembly connects the tank rigidly to a rigid backplate which is held closely applied to your back, and there's no room for shifting. (I can tell you that if your harness is a bit loose, you will REALLY know about it with doubles!)

Once the gear is stable, you need to assume a normal diving position (horizontal, knees bent) and try to hover. If you stop moving, what happens? It sounds as though you will tilt feet down, which suggests you need to move more weight up onto your back (assuming you have weight to move). If you have no weight to move, you can try moving the tank up, within the limits of what you can stand for comfort and also reach your valve.

Respectfully, I'll suggest that if you got into your old gear and tried to do what you are doing now -- hover motionless, in perfect horizontal trim -- you might have the same degree of difficulty. Most of us have been surprised and less than thrilled to discover we were stabilizing ourselves a great deal by our motion through the water.

Diver0001, who I greatly respect, has made the point over and over again that a BP/W does not create a fine diver. I'll add that it doesn't destroy one, either. The failure is highly likely to be technique rather than equipment.

 

[Carribeandiver]

Thank you Colliam7 and TS&M for your help.
First, let me address some of Colliam7's questions. I am diving a 30# singles wing. Halcyon Eclipse with a 6# SS plate. I do not know if I have a STA or not, I do not think so, and I have two cam straps. The BP/W was purchased through a shop already put together. I am diving in a wetsuit. I have made a few dives with an AL80 and a few with LP77s. I carry no additional weight. I am 5'8", 185#. I have jets and XS Scuba Power fins. I mostly use the Power fins.
I dont know if the harness is loose or not. I have tightened it up and it doesnt feel loose but there is some play when I am underwater; although, not very much.
And I have tightened the cam straps as much as I can.
TS&M: perhaps I have an incorrect recollection of my jacket diving days but I seem to recall I could achieve buoyancy and trim. I distinctly remember diving in Cozumel about 2 feet off the bottom and hovering. It was the first time I felt the rise with a breath and descending when I exhaled. I also recall doing this successfully in Roatan last January. This position was achieved and maintained while motionless.
With the BP/W I have never come close. I will readily admit that the equipment is not the problem here but it is the diver's lack of skill. Although, it is possible that improper fitting gear or improper weight distribution or amount can compound the problem.
It seems much more difficult to fine tune the amount of inflation necessary to be neutral. I am always adding or subtracting and I know that isnt right. The rig works perfectly for almost everyone who employs it. The fault is mine and I recognize that. But there has to be something I dont know which is the purpose of this thread.

 

[RiverRat]

The fault is mine and I recognize that. But there has to be something I dont know which is the purpose of this thread.

Let me try this again. I hate it when I type a whole paragraph and it's blown away before you post it

I too am in the same boat as you. I've been diving a "hog" rig right after AOW (4 years) so I'm comfortable in a BP/W. I recently started a "buoyancy1" class with a GUE Instructor to prep for DIR-F and now my whole world has gone to pieces Actually the class was WAY more in depth than I expected and I've already gotten my moneys worth from it. I only had to make a few changes my rig. Added a long hose set, a clip to my primary reg and tighted up the crotch strap along with a few other tweaks. For the first time I understand what people meant by getting pushed forward at the surface. Never felt that before, to that degree anyway until this class. I think it was a combination of tightening the crotch strap, moving the tank up a bit for valve drills and most likely because I had my wing jacked up all the way while we did some exercise on the surface. Amazing what just a few changes can do. But I'll fix it. My trim is still good but my kicking technique sucks. The main reason I took this class. I'm so used to diving straight legged that I have to break the learned muscle memory and retrain to keep those heavy fins closer to my center of gravity. I learned the basics last year at the quarry but it's not quite the same as taking a class from a kick *** cave diver Anyway Monday we watch the video of last weeks dives (a key component) and then work on propulsion. I would say your best bet would be to find a DIR diver or Instructor help you out. I would have been hard pressed to get my kicking technique resolved on my own. In fact I know I've got a long way to go before it becomes natural. Not sure if anyone else is offering the same type of course I'm taking but I think it's fantastic for divers like us in transition mode as well as new divers. The other option is try to get as close as possible on your own and get comfortable in your gear then take DIR-F somewhere.

 

[ekewaka]

I am diving a 30# singles wing. Halcyon Eclipse with a 6# SS plate. I do not know if I have a STA or not, I do not think so, and I have two cam straps.

If you are using an Eclipse, then you have an STA. It will not work without one because are no holes for the cam straps.

 

[Diver0001]

On the surface it sounds like you have the right kit. I think you're going to need to get someone to look at you in the water. It's hard, for me at least, to visualize your problem

 

[DIR-Atlanta]

I dont know if the harness is loose or not. I have tightened it up and it doesnt feel loose but there is some play when I am underwater; although, not very much.

There should not be any "play" in the harness while you are wearing it. The only place where you may want it a little loose is the crotch strap, but even that should be snug enough to keep it from riding up.

I distinctly remember diving in Cozumel about 2 feet off the bottom and hovering. It was the first time I felt the rise with a breath and descending when I exhaled. I also recall doing this successfully in Roatan last January.

What was the depth on those dives? Deeper water tends to mask a lot of buoyancy problems, particularly when wearing a wetsuit. Part of the reason they do the Fundies class in 20-30 feet of water is because it is much harder to maintain a stable position in shallow water. If you can master it there, then you can master it anywhere.

I will readily admit that the equipment is not the problem here but it is the diver's lack of skill. Although, it is possible that improper fitting gear or improper weight distribution or amount can compound the problem.

The placement of the weight is almost as important as the amount of weight. If all the weight is around your hips, then your legs will tend to drop more. You may need to transfer some of the weight to the cam straps on the tanks to even things out. Also, leg position is important, particularly with the Jetfins. If your legs are extended too much, then that will also throw off your trim.

It's also critically important to arch your back. Not doing so will cause your thighs and knees to drop.

It seems much more difficult to fine tune the amount of inflation necessary to be neutral. I am always adding or subtracting and I know that isnt right.

If you are properly weighted and your wetsuit isn't too thick, then you shouldn't really need to put too much air in your wing. Most of it should be added at the beginning of the dive (when you are the most negative), and by the end of the dive (when you are on your shallow stops), there shouldn't really be any air at all in the wing. Also, the buoyancy shift on an 80cf tank is only about 5 lbs, which in many cases can be compensated for just with your breathing.

I know that in my case on an average rec profile dive in warm water (wearing a 3mm suit), it's rare for me to put more than a burst or two of air in the wing throughout the whole dive. On shallow dives (20-30 feet) I don't even touch the inflator except when I am at the surface.

I know this is frustrating for you, and particularly so given the lack of any sort of local support for what you are trying to do. Unfortunately, it's a combination of a great many things that contribute to that "perfect trim", so it's difficult to diagnose without actually seeing what is going on. Just keep working at it, and I know eventually it will start to "click".

 

[ReefHound]

With my knees bent, the weight is pushed on my hips which causes my legs to drop which results in more of a 20 degree vertical then the horizontal pose I am desperately seeking. And yes, my fins are now negative which adds to the weight distribution problem.
This style of diving with bent knees and fins up is to prevent silting, right? At least, that is what I have determined to be the reason. But, isnt that counterproductive to perfect trim because of the weight distribution and load on the hips?
Doesnt that style naturally cause that 20 degree angle more than it helps the perfect horizontal position?

This makes absolutely no sense and defies the laws of physics. Your center of gravity is somewhere in your midsection. The further from the center of gravity a given weight is located, the more pronounced effect it will have. The unit "foot-pound" means the force of one pound at one foot distance. At two feet distance, a one pound weight will exert 2 foot-pounds force. So bending your knees and bringing your fins and lower legs closer to your center of gravity actually reduces the downward force.

With your BC rig you were probably wearing additional weight. Was it located high such as in trim pockets? It's possible the plate has brought the weight lower than before. I would first try lighter fins, such as OMS Slipstreams in place of SP jets. If that doesn't solve it, maybe use an aluminum plate and add weight to the upper cam band or top of plate.

 

[lamont]

to fix head-up / feet down trim:

1. try taking off weight off your weightbelt if you are overweighted

2. take weight off your weightbelt and move it to a steel backplate if you're diving an aluminum one

3. take weight off your weightbelt and move it to a steel tank

4. take weight off your weightbelt and move it to a weighted STA

5. take weight off your weightbelt and move it to tank weights if you have to

6. adjust your weightbelt so that your weights are more to the front of your torso than the back (when standing)

7. Dropping your head down and bending your knees at an angle should actually help to fix head-up trim. The prescription for head-down trim is to keep your head up, arch your back and extend your legs (and both of these postures together form a 'CG drill' if you switch between them).

As an added bonus adding more weight to your tank/backplate will reduce the tendency of the wing to tip you face-down in the water.

Fundamentally if you've got a bladder up high on your torso and weights around your waist with everything else being roughly neutral the bladder is going to try to go up and the weights are going to try to drop and you're going to wind up horizontal. You have to fix the distribution of your weights.

I had a heck of time with trim and floating on the surface with 20# weightbelt, steel backplate and Al80s. There's video of me in my DIRF class just completely giving up and floating vertical because I got tired of trying to fight it (to my credit my feet and hands were still and I was neutrally buoyant, but I just wasn't in the right orientation). Switching to steel tanks and dropping weight off the weightbelt helped a lot. Nowadays I use a weighted STA with a steel backplate and steel tanks when diving singles (that didn't work so hot the first time I tried it, though, but after I got used to diving head-heavy doubles I can use all the weight I can get up high when diving single tanks).