Plate positioning on back

Which aspects of a bp/w control how high the plate sits on your back? Is it the length of the shoulder straps? The size of the plate? How short the crotch strap is? The phase of the moon when the plate was manufactured?

I ask because I have been having some issues with my head touching my first stage when using a single tank rig. Despite adjustments to just about every part of my harness*, I have not been able to make any sort of improvement. It seems that nothing I do has any effect whatsoever on where the plate sits on my back. And, since the placement of the wing does not affect how close the valve (and hence first stage) sits to my head and the tank is already as low down in the cam-bands as possible, only the placement of the plate on my back can affect the position of the first stage.

First I tried adjusting the shoulder straps. I have gone from having them loose enough to pull my whole arm out while out of the water ... :11: ... to the recommended 3 fingers width spacing.

I also tried adjusting the crotch strap reasoning that it could pull the bottom of the plate downwards however I can never seem to get enough tension for this to happen. What usually happens is that my waist strap is pulled downwards instead of the plate.

I've even tried rotating the cylinder in the cam bands so that the first stage is at an angle to my head. That just made it worse!

Thinking about it logically, the best way to stop my head touching the first stage is to move my plate down on my back. But I have no idea how to go about doing this as any adjustments I make to the harness seem to have negligible effect on the plate.

I suppose that I could just get used to the first stage touching my head. The problem is that it really REALLY bugs me. It is almost to the point that I get claustrophobic when I feel that little piece of metal behind my head. The harness could be as loose as possible (such as when I could pull both arms out) and I would feel trapped and constricted simply because I can't move my head. It gets to the point where I can't enjoy the dive at all because I am continually irritated every time I try to move my head. I feel like I can't concentrate on important things like buoyancy and proper breathing because of the continual background irritation. Its almost like being constantly tickled ... not painful but VERY annoying.

My head only touches the first stage when I look forwards i.e. when I arch my back. If I am looking straight down it never happens. What this means is I usually end up paying lots of attention to whatever is directly in front of me and no attention to proper trim. :no

*for the record I use a single piece of webbing, hog style harness. I have the plate positioned so that I can just about touch the top of it with my fingers. I always put the top cam band just where my dumpy 12L steel cylinder breaks, on the shoulder.

The plate fit is one thing. The height of the tank on the plate is another.

Equipment Images

That's how the plate should look relative to your back.

Have you tried repositioning the tank on the plate with the cam bands? Yes, I know your trim might be different, but that can be corrected.

Well, the tank is as low down in the cam bands as it can go. If I were to move it up then I would only be making the problem worse.

Can you get somebody to take some pictures of you in your gear (on land)? I'm having a really hard time picturing this.

The plate should ride so that the top of it is just below the big knob you can feel at the base of the back of your neck. This will generally mean that doubles will ride correctly, but with a single tank, you have so much more latitude in where the tank IS that you can generally get it where you need it to be. Honestly, when I dive a single tank, the top camband is at least six inches below the shoulder of the tank, so it's really hard for me to figure out how you could have your tank with the top camband at the shoulder and still have the first stage in the back of your head.

Pictures would help us sort it out.

Thats an excellent idea. Will work on that but it will be some time before I get the opportunity because I have no time to dive during the week. *sigh*

I will add that on land when I tilt my head back I can't feel it but it always happens in water. That suggests that the plate is "riding up" which points to tightening the crotch strap ... which seems to have no effect

Not that I know much about backplates, seeing how I just got one and have never dove it yet, but hammerhead makes a nice sta that has a extra cam band slots. which may help lower the tank more.

I'm having a hard time thinking of how loosening the shoulder straps didn't help. With them looser you can pull the bottom of the plate down so the waist band is placed lower on your body. Make sure the waist band is nice and snug and the plate shouldn't go anywhere.

How tall are you? I'm 5'2" and I have the same issue but it hasn't bugged me enough to resolve.

Regardless if you are using a bp/wing or jacket style bc the only way your head is going to hit the first stage, when you tilt your head back, is if the bc is to low on the cylinder.

If you loosen your shoulder straps the bc will do nothing but ride up and down on your back. You can shorten your crotch but you can only tighten it so far.

All my regulators use DIN so I have to use a yoke adaptor which makes it stick out farther (or closer to my head/body) from the tank and I don't have the issue of my head hitting it.

Pictures of where you have your bc attached to your tank will help us view your set up.

Cheers

Chris

4sak3n:

Which aspects of a bp/w control how high the plate sits on your back? Is it the length of the shoulder straps? The size of the plate? How short the crotch strap is? The phase of the moon when the plate was manufactured?

I ask because I have been having some issues with my head touching my first stage when using a single tank rig.

Click to expand...

Loosen the shoulder straps and snug up the crotch strap. As a **TEST** snug the crotch strap quite a bit, and make sure your waist strap is snug also. This combo will lower the plate.

Keep in mind that when using a DSS plate and direct mounting the tank, in other words using the camband slots in the plate WITHOUT a STA, the tank can be mounted much lower than can be accomplished with most STA's. That's because the top camband slot in the plate is much lower than the slots in most sta's.

The other suggestion is to simply become accustomed to contact with the first stage.

Take a look at a set of doubles. The tanks are much closer to the diver, and the manifold and Isolator is close behind your head. My hoods develop a dent from contact with the Iso. That's just the way it is...

Tobin

Here is a photo of my rig set up on the lawn.

Hope you can make out how low the cylinder is in it. Local regulations here in SA stipulate that a cylinder must be painted yellow along the body and grey on the shoulder.

Since you can't see any yellow above the top cam band it must be right at the shoulder.



Edit: to answer some things brought up, I am 6' 2" and will look at getting pictures of me wearing the kit dry. Not sure if the pictures will help though because as I stated I don't have the problem on land.