Diving without releasable weight

[Eric Sedletzky]

Sort of an aside, but back in the late 60's I was taught that from a full to nearly empty steel 72 tank there was about a 5 lb bouyancy swing. To weight myself properly to be neutral (no BC mind you), I was taught to weight myself with a full tank so I'd be light at the end of the dive because it was just assumed I'd have game in my bag and that weight would offset the increased tank bouyancy at the end of the dive. Never was sure if that was exactly the way it worked but I stayed pretty neutral throughout a dive and everyone I knew followed that approach.

That 5 lbs. can actually be reduced down to about 2 lbs.
First, when you start out your dive you can be holding more air in your lungs from anticipation and excitement.
Second, when you first get in the water your suit is warm and the neoprene cells are fully inflated from the warm sun and ambient topside dry temperature. When you dive for a while your suit cools and slowly becomes less buoyant as bottom time goes on. This counters the loss of air in your tank. By the end of the dive you’re also more relaxed and not holding as much air in your lungs so that further helps offset buoyancy swing.
In some cases it is possible to counter almost the entire 5 lb swing.
It helps to have huge lungs to use too, and if you have to finding the appropriate rocks.

 

[CT-Rich]

I haven’t had a chance to read this entire thread, but I have had two occasions to drop weights. My drysuit rig has a DUI weight harness that holds 24 lbs and another 12 lbs on WI BCD. Shortly after I started diving with the dry suit, I was on the surface looking at a long surface swim in fairly rough water. THe neckseal on the drysuit was quite tight, and while it wasn’t a problem underwater, trying to swim on the surface it was restricting blood flow to my head. Overtime this caused a build of CO2 with the nasty panic sensation that goes with it. The harness weights were keeping me almost vertical the water. Any air I pumped into the suit just pooled around my shoulders and wasn’t really fixing it. I opted to drop the weights for long swim in. With out the weights, my legs floated up an I was able to get blood flow to my head. I calmed down and was able to swim in.

The second time I dumped weights was on a night dive. I was in my wetsuit and had 12 lbs on my belt and 12 lbs in my BCD. I had a mostly full tank and my dive buddy was low on air. We had surfaced to take a compass baring to our exit point. My should dump on BCD jammed open and I could not stay buoyant on the surface. I had plenty of air and could have made it to shore on the bottom I did not want to separate from my buddy because it was night and open ocean and I did not want to have us separated.

Neither of these times were at depth and neither of which I could recall attribute to poor planning of the dive (that is the most common refrain I here when people talk about wanting no ditchable weight). I am doing mostly cold water dives so, there is always a lot of extra buoyancy involved in thermal protection. Removable weights are a form of redundancy, incredibly cheap and insanely reliable. Why anyone thinks it is a good place to cut corners is beyond me.

 

[Diving Dubai]

In my waters, there have been several fatalities which most probably were caused by a catch bag not being ditched.

Really, that was the cause or was there something that happen first, and then their choices were secondary causation’s

 

[Stoo]

My ADHD prevents me from reading this entire thread, but let me toss in my $0.02 worth.

In the tropics, I have 4 - 6 pounds in trim pockets on my Zeagle Sport. Can't dump them, and even if I could, I don't think it would make much difference. I shot of air into my BCD would accomplish the same thing, as would a couple of robust kicks.

When I dive at home, I'm wearing double steels and a drysuit. If I'm wearing my twin steel LP 80s, I wear 12 pounds of lead on a belt. If I'm wearing my HP 130s, and I have no weightbelt at all... so back to no ditchable lead.

The vast majority of my dives require some deco. It might be 5 minutes or it might be a lot more. Our local Dive Doc has a favorite saying: "We can fix bent, we can't fix dead!"

By that logic, if I blow off 5 minutes of deco, and get a little bent as a result, I am very confident that "Dr. George" will unbend me with a minimum fuss. Bear in mind, we have a chamber in town.

On the other hand, diving on a new wreck 1 1/4 away a couple of weeks ago, I'd spent 30 minutes in 210 - 220', and wracked up an hour plus of deco, starting at 100'. If I blew that off, I'd be bent to death (if that's a thing).

So getting back to your original question, I guess the answer for most is that dumping some lead might be ok, even beneficial. But for many others, it might be fatal.

I guess my answer then is, "It depends".

 

[rjack321]

When I dive at home, I'm wearing double steels and a drysuit. If I'm wearing my twin steel LP 80s, I wear 12 pounds of lead on a belt. If I'm wearing my HP 130s, and I have no weightbelt at all... so back to no ditchable lead.

you are either underweighted in the 130s or overweighted in the 80s.
empty both of these cylinders are not that different in buoyancy (assuming all other gear stayed the same here)

 

[Steve_C]

I have integrated weights. You pull a handle and the pocket comes out. If you wanted you could dump some of the weight and replace the pockets.

When I did some practice taking gear off and putting it back on I would take out the pockets and place in my wet suit (5 or 7mm). Then off and on was easy. Then put the pockets back in.

I have had a buddy have the total failure of the top valve on his BCD. If he would have had to stay at the surface a weight dump would have been desirable. He is a very experienced diver so by going up the anchor in a head down position he was able to keep some air in the bcd.

 

[Steelyeyes]

I have integrated weights. You pull a handle and the pocket comes out. If you wanted you could dump some of the weight and replace the pockets.

When I did some practice taking gear off and putting it back on I would take out the pockets and place in my wet suit (5 or 7mm). Then off and on was easy. Then put the pockets back in.

I have had a buddy have the total failure of the top valve on his BCD. If he would have had to stay at the surface a weight dump would have been desirable. He is a very experienced diver so by going up the anchor in a head down position he was able to keep some air in the bcd.

I had a similar issue with my BP/W which was further complicated by descending into complete zero visibility. Took me about 15 feet or so to figure out that the air I was putting in the wing wasn't doing anything. Luckily I was in a drysuit. Added air to the suit, got back to the surface and terminated the dive in good health.

 

[Stoo]

you are either underweighted in the 130s or overweighted in the 80s.
empty both of these cylinders are not that different in buoyancy (assuming all other gear stayed the same here)

LOL.. I'm good, but thanks.

If anything, I'm a little light with the 130s. If I let them get "emptyish", I am a little more buoyant than I'd like, but I never let them get that low, so no biggie.

My undies sometimes change a little with the 130s since I tend to wear those on deeper/longer dives.

 

[drbill]

In 57 years of diving I can't remember a single time when I've had to drop my weights. However, all mine are releasable. Although I don't currently do it, my preference would be for half my weight in releasable weight pockets and half on my belt.

 

[tridacna]

I don't ditch weight.

I have never seen anyone benefit from ditching weight..

I was stranded on the surface at night by a dive boat. Ditching 12 lbs was a fantastic benefit to my overall bouyancy in a BPW while waiting to be rescued. (2 hours later).