Whats my problem with sinking (weights) ??

[SilverNU]

Weight check...

I deflate my BC.. take a deep breath.. and should float at eye level.. correct??


When I do this.. I seem to sink below this eye level mark.


Problem being...when I go to start a dive.. I get about 5 feet down and then have to work on getting down any further.

Once im down 15-25 feet... I seem to do fine at being able to sink.


Am I doing something wrong??

 

[Mr Carcharodon]

So you float somewhere between just below eye level and 15 feet with a normal breath and full tank? Really you should sink at the start of the dive with a normal breath since you are overweighted by the weight of the gas in your tank. That is normally about 6 pounds for 80 cubic feet. You may just have higher than normal lung capacity and the associated greater buoyancy. Good for you. Make sure you exhale completely before deciding you are under weighted. But if you still do not sink add two pounds and try it again.

 

[on_two_wheels]

If you have a near empty tank, you're overweighted on that weight check. As for difficulting descending, believe it or not there's a few things to consider. First, I'm assuming you're relatively new so bare with me. If you're not, then this is an odd question to post.

It's easy to leave air in your bcd. Making sure it's as empty as possible is key.

It's common for "balance finning" while trying to descend. Keep the feet locked still and together, fins pointed down.

Make sure to exhale fully to begin descent. Personally, I do a shallow inhale when needed during initial descent, then another deep exhale to go a bit further. By the second exhale, I'm going horizontal and descending no problem.

Good luck.

 

[vinegarbiscuit]

No, it's not necessarily correct. It depends on what sort of exposure protection you're wearing and what sort of tank you're using. Diver A may be able to float at eye level at the start of a dive in a 7mm suit and an Al80, for example, but diver B in a dive skin and a Al63 may not. See Stupid Instructor Article (no implication that anyone's a stupid diver, so I hope no offense is taken...plus, it's a hilarious site!) for a full explanation about the funkiness of this conventional wisdom.

 

[on_two_wheels]

No, it's not necessarily correct. It depends on what sort of exposure protection you're wearing and what sort of tank you're using. Diver A may be able to float at eye level at the start of a dive in a 7mm suit and an Al80, for example, but diver B in a dive skin and a Al63 may not. See Stupid Instructor Article (no implication that anyone's a stupid diver, so I hope no offense is taken...plus, it's a hilarious site!) for a full explanation about the funkiness of this conventional wisdom.

He was doing a weight check. If properly weighted, you've accounted for exposure suit, tank, BCD, etc. While some people are inherently negatively buoyant while others are positive, initial weighting should be established with those other variables in mind, right? Maybe because I do live in so cal this makes sense to me. Ultimately, though...I agree with many others that the best weight check is done at the end of a dive at 15 ft.

 

[vinegarbiscuit]

He was doing a weight check. If properly weighted, you've accounted for exposure suit, tank, BCD, etc. While some people are inherently negatively buoyant while others are positive, initial weighting should be established with those other variables in mind, right? Maybe because I do live in so cal this makes sense to me. Ultimately, though...I agree with many others that the best weight check is done at the end of a dive at 15 ft.

Initial weighting should certainly be established with those other variables in mind, but a weight check at the end of the dive confirms whether one's initial estimate was correct. I reckon we're in agreement here.

 

[TSandM]

SilverNU, we simply don't have enough information to evaluate your situation.

Are you doing this at the beginning of a dive? Are you diving wet or dry? What size tank are you using?

If you are doing a weight check at the beginning of a dive, you should be negative, with an empty BC and a normal breath, by the amount of gas in your tanks that you intend to use and exhaust during the dive. That's about 5 lbs for an Al80. And that means that, with an empty BC and a normal breath, you should sink.

If you are using heavy exposure protection (7mm or more), there are those who would suggest that you weight yourself neutral at the surface with a full tank, at the beginning of the dive, on the basis that your wetsuit will lose trapped air, compress at depth, and not rebound fully.

But there are many factors that can contribute to difficulties descending. One is that, if you have followed the usual teachings and vented your BC and exhaled at the surface, at a few feet beneath the surface you will need to INHALE -- and when you do so, if you fill your lungs, you become much more buoyant, and likely will stop sinking. If, at that time, you are still vertical, and finning to maintain your balance, in which direction are your fins driving you? UP!

What NWGratefulDiver taught me, when I was new, was to hold my BC inflator hose up and vent it, and INHALE. Just as my mask hit the water, I was to EXHALE and hold it. At the same time, I was to cross my ankles with my knees slightly bent. This kept me from kicking myself back up, and also, because of the bent knees, tended to rotate me into a more horizontal position for descent, which meant that if I did kick, I wouldn't go back up.

Hope some of these tips help you. Difficulties descending are very common with new divers, and although proper weighting is necessary, the solution is rarely more weight.

 

[FireInMyBones]

Weight check...

I deflate my BC.. take a deep breath.. and should float at eye level.. correct??

Well...yes...with a 7mm suit and an Al80.

When I do this.. I seem to sink below this eye level mark.

Is your tank almost empty?

Problem being...when I go to start a dive.. I get about 5 feet down and then have to work on getting down any further.

Once im down 15-25 feet... I seem to do fine at being able to sink.


Am I doing something wrong??

All you should have to do is exhale to sink. Perhaps there is air getting caught in your BC. Happens to a friend of mine often. It is an older one and does not vent very well.

 

[1_T_Submariner]

I agree if this is the beginning of the Tank you should sink not float at eye level. If this is at the End you are correct on the float at eye level method.

I'll probably get flamed for this but, I prefer to be weighed slightly more than the eye level method. Like 2lbs more, I feel that I have more control. I know about being streamlined, overwieghted makes you use more air etc..... Thats just how I dive.

 

[Quero]

SilverNU, I sometimes see this in students. When I've seen it, the students exhale to get off the surface, and then when they're a little ways down they take a breath in and stop descending. This breath in serves to buoy them up--not all the way to the surface, but enough to make it seem that they can't get down any further. I generally have to indicate to them through gestures and hand signals to blow out, and after a little pause for the delayed effect, they begin to descend again. Is it possible that you are inhaling at that depth you get "stuck" at and your full lungs are preventing you from descending?