Too much Weight

[Piccola]

Since it was my 1st ocean dive and the first time I was all geared up (with 7mm suit) I think I wasn't expecting to feel so heavy at the surface. My regulator was in freeflow so as I was trying to ascend calmly, I felt like I had to really kick, if I stopped kicking I started sinking. It might of seemed more dramatic to me at the time since I knew without inflating my bcd, I would not have been able to keep my head above water and I was going to quickly be without air in my tank.

I have done a bouyancy check when I have changed from fresh to salt water (gear is the same). It just seems I have difficultly breaking the couple of feet mark. As I am getting more dive time I am trying to make slight changes in my weights. I dove with some folks a little while ago who seemed to think I was doing a good job with bouyancy control and horizontal swimming. I think I am a bit more critical (of me) and want to find the right mixture. In the end I feel it is all a part of understanding the elements of diving and learning from it. This board has been a great source of information.

 

[Walter]

The 10% rule

There is no such rule. It's a crutch of the lazy. After seeing Bob, Lynn and Kevin have already replied, I'm sure you have all the info you need.

 

[Blackwood]

Short of grossly overweighted, the amount of weight you carry has little impact on measurable air consumption.

Not that gas consumption is the only issue.

I'll skip most of them and go to: too much weight = too much air = difficulty controlling ascent.

 

[matt_unique]

Not that gas consumption is the only issue.

I'll skip most of them and go to: too much weight = too much air = difficulty controlling ascent.

Air consumption is the usual reason given for the consequences of carring more lead than you need.

Your weight has nothing to do with the process for maintaining buoyancy unless your system cannot support neutral buoyancy or you are too light to stop/initiate a descent. Otherwise you add air to be neutral or positive, release air to be neutral or negative. This is the same for X lbs or X+10 lbs of lead and has nothing to do with ascent problems. If you are carrying X + 10 lbs you need to hold your inflator open for a few more seconds to get neutral for example.

The weight discussion (short of grossly over or grossly under) is about ego. (Referencing the first post). The arguments are all correct and relevant in a test tube, but not in open ocean diving. A slight change in current, hunting, photography, anxiety, etc. will affect air consumption LONG before the X + 10lbs on your weight belt.

--Matt

 

[MXGratefulDiver]

Air consumption is the usual reason given for the consequences of carring more lead than you need.

Your weight has nothing to do with the process for maintaining buoyancy unless your system cannot support neutral buoyancy or you are too light to stop/initiate a descent. Otherwise you add air to be neutral or positive, release air to be neutral or negative. This is the same for X lbs or X+10 lbs of lead and has nothing to do with ascent problems. If you are carrying X + 10 lbs you need to hold your inflator open for a few more seconds to get neutral for example.

The weight discussion (short of grossly over or grossly under) is about ego. (Referencing the first post). The arguments are all correct and relevant in a test tube, but not in open ocean diving. A slight change in current, hunting, photography, anxiety, etc. will affect air consumption LONG before the X + 10lbs on your weight belt.

--Matt

That hasn't been my experience at all ... either as a diver or someone who regularly works with divers trying to improve their performance.

Proper weighting plays a large role in good buoyancy control AND overall gas consumption ... the latter in large part due to the fact that when you're struggling with your buoyancy control it WILL affect your breathing control ... which is a major determinant in gas consumption.

Ego has nothing to do with it ... you need what you need, but carrying more than you need WILL affect how well you dive. More experienced divers can learn how to compensate for the effects of overweighting, but that's an adaptation. Newer divers who are overweighted will work harder to maintain proper buoyancy control than they would if they were weighted properly.

... Bob (Grateful Diver)

 

[TSandM]

All I can say is that, when I've taken ten or so pounds off a new diver, they come up from that dive saying, "Wow, that was so much EASIER!"

 

[matt_unique]

I agree struggling with buoyancy will burn gas. If one can remove weight by all means do it and of course it's more comfortable (even in carrying gear on the surface). My comments are about the supposed consequences of being slightly over weighted and how some think the amount of lead is a badge of honor.

I can't comment from the perspective of teaching students. If a student is unable to get neutral with X lbs, and perhaps augments this with finning against the weight to stay at a given depth for example, I can certainly see how adding more weight would add to the work against the weight and air consumed, etc. This is a problem of knowing how to be become neutral with any amount of weight, regardless of the actual weight and not a problem with the weight by itself.

Anyway my perspective was from a diver, perhaps experienced, who dives first with X lbs. Add 10 lbs for dive #2 and if other variables remain constant, you will not find a measurable difference in air consumed. This diver simply needs to add a bit more air after the descent to get neutral and vent a little less air for the ascent. Or looking at it another way, instead of starting the descent with an empty system, they must leave a small amount of air and the rest of the dive remains constant, with that extra air always there.


--Matt

 

[Blackwood]

Air consumption is the usual reason given for the consequences of carring more lead than you need.

Yah.

Your weight has nothing to do with the process for maintaining buoyancy unless your system cannot support neutral buoyancy or you are too light to stop/initiate a descent.

I agree. The process is the same. I also agree that 10 pounds too heavy is very manageable... for a somewhat experienced diver. I assumed we were discussing new divers. In my experience (both as someone who remembers being a new diver and as someone who sometimes gets wet with new divers), they tend to have issues adequately venting air even when properly weighted. This problem is exacerbated by increasing in the volume of air necessary to be neutral.

 

[dave4868]

Since it was my 1st ocean dive and the first time I was all geared up (with 7mm suit) I think I wasn't expecting to feel so heavy at the surface. My regulator was in freeflow so as I was trying to ascend calmly, I felt like I had to really kick, if I stopped kicking I started sinking. It might of seemed more dramatic to me at the time since I knew without inflating my bcd, I would not have been able to keep my head above water and I was going to quickly be without air in my tank.

I have done a bouyancy check when I have changed from fresh to salt water (gear is the same). It just seems I have difficultly breaking the couple of feet mark. As I am getting more dive time I am trying to make slight changes in my weights. I dove with some folks a little while ago who seemed to think I was doing a good job with bouyancy control and horizontal swimming. I think I am a bit more critical (of me) and want to find the right mixture. In the end I feel it is all a part of understanding the elements of diving and learning from it. This board has been a great source of information.

What does "feeling heavy at the surface" mean? Was it the additional weight for saltwater? Were you surprised that you needed to inflate the bcd to keep from sinking?

That's how things are at the beginning of the dive. With wetsuit compression at depth, there's even more of a tendency to be negative.

Of course, you'll feel less "heavy" near the end of the dive when your tank is nearly empty and you're in shallow water.

You say you had to really kick to ascend when you had the free-flow, but again, you don't mention putting air in the bcd. Did you inflate your bcd or not? Was that the issue?

Certainly, realizing you had to rely on your bcd to remain afloat on the surface could be a little scary, but needing air in the bcd is expected until the weight of the air in the tank is almost gone.

I'll just add that my 10-year-old PADI OW manual suggests setting up the weighting a little differently, with the goal to be a bit positive at the end of the dive at the surface. I think they figure the compression of the neoprene at the 10-foot safety stop would allow one to be neutral at that depth.

That wouldn't be my preference, since I might want to cruise a bit at five feet, for instance. Or I might be in surge and needing to fin down occasionally to hold the safety stop. I'd rather have a little more weight.

Either way, you'll get used to relying on and trusting your gear and training.

Also, do you have any idea why you feel it's difficult to descend from the surface at the beginning of the dive? If you've got your weighting as I described, you'll be about 6 pounds negative with the bcd empty (assuming an al80).

Do you think your buoyancy check was off a bit? Would you be willing to share details of how you did that buoyancy check? Did you follow PADI guidelines? The old PADI guidelines would tend to keep you "lighter" than the method I suggested.

I'd check it again and just follow the basics for adjusting your weight to the minimum needed to still be about neutral with an empty tank.

It may not feel right at this point, but it will be, I think.

Dave C

 

[donacheson]

10% is a starting point, assuming a full set of gear and aluminum tank. You must then get in the water and test it. The PADI weighting check fulfills that. Empty your BC, hold a normal breath and adjust your weight till you float at eye level. Then add weight to compensate for the air in a tank that you will use during the dive, about 5 pounds. Do your dive, and when finished, write down how much weight you used, and what gear you used, and whether it was heavy or light at the end of the dive. Keep track of this and keep tweaking till you get it right.

FYI, for those new divers who think they would benefit, the PADI Peak Performance Bouyancy Adventure Dive or Speciality covers weighting in detail. [/end training plug]

The "PADI weight check", which has been around and used by other diver certification agencies for decades, makes no sense. It certainly didn't weight me correctly.

Minimal weight obtains by being neutral with an empty BC, a near empty tank, breathing normally just below the surface. While I'm not sure what "hold a normal breath" means, floating at eye level with a full tank and adding "weight to compensate for the air in a tank that you will use" means that you'll be floating with half your head out of the water at the end of the dive. Half your head weighs about 5 pounds. I don't want to be 5 pounds light when approaching the surface after a safety hang.

In my own case, I was certified in 1978 and weighted using the "PADI weight check". In retrospect I suspect it "worked" because we wore 1/4-inch wet suits, which compress rapidly with depth, and we never even heard of a safety stop. Our diving was done on wrecks hugging the bottom and grasping an anchor line to ascend.

It wasn't until I started diving in the tropics without a thick wet suit and with the need to be neutral throughout the dive that I had to learn how to weight myself properly - being neutral with an empty BC, a near empty tank, and breathing normally just below the surface. There's no problem with an extra pound or two, but underweighted by even a few pounds can be exhausting.