Integrated weights?

[Coldwater_Canuck]

No they are all different. I believe this is so if you need a new pocket you can only order one through them. But perhaps I am too cynical My weights are varying types and varying sizes, I tend to mix and match a bit. Some are threaded, some are not. I have 0.5kg, 1kg, 3lb and 6lb weights, and this seems to be enough these days to use all kinds of weight variations depending on my setup.

That's what I was afraid of ...

Fair enough! I did weight checks in OW (kinda) but was always finning slightly, and also holding my breathe unconsciously so I ended up quite overweighted. I think a lot of people are similar. But if you find yourself floating up it sounds like you are underweighted. Sometimes I add an extra 2lb or so when I dive shallow as often the last bit of the dive is spent at around 10ft, and I might only have 20-30bar left. Aluminium tanks are a pain I find, I hate having to wear the extra weight, and also the large buoyancy change with them. Luckily, locally steel is more common and most rental tanks are steel. Doesn't seem to be this way in other places though.

What do you mean "finning"? I've never heard that term.

I was told before that aluminum tanks were more popular in warm water spots because you don't have the thick wetsuits keeping you so buoyant, but sounds like even you in Australia find them a pain. Most the places in Seattle rent primarily steel, but one weekend there were a bunch of OW classes and I had trouble finding any place with rental gear available: the place I did find only had aluminum tanks. It was better than nothing, but in the future I'm going to try to avoid the things as much as possible (while I'm buying my own gear, I'll continue renting tanks for awhile).

 

[Sas]

What do you mean "finning"? I've never heard that term.

Finning with my fins, so like wiggling my legs to stay upright. I was doing it unconsciously. For a while I would cross my legs when descending, to help me go under. Now I no longer do it accidentally and am usually horizontal when descending so finning doesn't really make me stay on the surface.

I was told before that aluminum tanks were more popular in warm water spots because you don't have the thick wetsuits keeping you so buoyant, but sounds like even you in Australia find them a pain. Most the places in Seattle rent primarily steel, but one weekend there were a bunch of OW classes and I had trouble finding any place with rental gear available: the place I did find only had aluminum tanks. It was better than nothing, but in the future I'm going to try to avoid the things as much as possible (while I'm buying my own gear, I'll continue renting tanks for awhile).

Where I dive, temperature ranges from 8C - 21C, so most of the year is fairly cold for diving (most people I know stay out of the water over winter), hence the steel tanks. People are mainly in 7mm or drysuits. I notice further up North where the warm water is (Australia is not all warm diving! ), people use aluminum tanks.

 

[Coldwater_Canuck]

Finning with my fins, so like wiggling my legs to stay upright. I was doing it unconsciously. For a while I would cross my legs when descending, to help me go under. Now I no longer do it accidentally and am usually horizontal when descending so finning doesn't really make me stay on the surface.

Ah I see. I'll try to remember this and make sure I'm not doing it without noticing.

Where I dive, temperature ranges from 8C - 21C, so most of the year is fairly cold for diving (most people I know stay out of the water over winter), hence the steel tanks. People are mainly in 7mm or drysuits. I notice further up North where the warm water is (Australia is not all warm diving! ), people use aluminum tanks.

Ah I see, sorry didn't realize the southern part of Australia was actually that far south that it was cold water diving. So I guess the thing about aluminum tanks in warm water was correct.

 

[rstofer]

Okay thanks. What's weird though is on most of the big scuba sites (I'll probably buy the weights locally, just using the sites as kind of a price guide) I never see any weights sold that look like they belong in the BCD. Are the weight pockets the same size with the same clip across companies?

You usually use bag weights. They come with a cloth or a neoprene bag containing lead shot. These are stuffed into the weight pockets. You can use solid weights but you won't be able to fill the pocket due to form factor. This wouldn't be important if you didn't need every cubic inch of capacity.

As to that aluminum tank: get a 6# tank weight strap or a pair of 3# cam band pockets. You can use these in addition to your normal weight belt when you get stuck with aluminum tanks. FWIW, aluminum tanks are not necessarily evil. A good case can be made that with some highly negative BP/Ws, a highly compressible wetsuit and a very negative tank like an HP 100 you can be so negative at depth when starting a dive that should your wing fail (totally), you won't have enough ditchable weight to allow you to do a swimming ascent. Effectively, you're pinned to the bottom. There's a buoyancy calculator spreadsheet over on the Equipment -> BCs ... forum. It is interesting to play with.

If you are using 40# of weight, you absolutely do not want to put all of this in the BCD weight pockets for all the reasons we have been discussing throughout this thread.

First, your pack will weigh nearly 80#. Second, if you drop a pocket, no power on earth will keep you from rocketing to the surface.

Consider splitting the weights between a harness and the BC. Put as much weight in the harness as you can consistent with being buoyant at the surface in your wetsuit but without your BC. This way, if you need to adjust your BC or reattach the tank that is falling off, you can float without the BC.

Put the rest of the weight in the BC consistent with the fact that the BC must have enough lift to support the weights, the tank, the regulator and any other equipment tied to the BC. It is important that the BC be capable of supporting itself on the surface without the buoyancy of the diver in a wetsuit.

This cold water diving takes a lot more thought than warm water diving where you can just toss 6# in the weight pockets, grab an Al 80 and start making bubbles.

Richard

 

[Coldwater_Canuck]

You usually use bag weights. They come with a cloth or a neoprene bag containing lead shot. These are stuffed into the weight pockets. You can use solid weights but you won't be able to fill the pocket due to form factor. This wouldn't be important if you didn't need every cubic inch of capacity.

The BCD I used during my OW as well as the (different) one I'm thinking of buying both have those pockets at the front that fit a special type of weight that molds to the pocket with a clip. I know what these weights look like as I installed them myself for the OW course and normal rentals, but I haven't seen anything looking like them on the major scuba sites.

As to that aluminum tank: get a 6# tank weight strap or a pair of 3# cam band pockets. You can use these in addition to your normal weight belt when you get stuck with aluminum tanks. FWIW, aluminum tanks are not necessarily evil. A good case can be made that with some highly negative BP/Ws, a highly compressible wetsuit and a very negative tank like an HP 100 you can be so negative at depth when starting a dive that should your wing fail (totally), you won't have enough ditchable weight to allow you to do a swimming ascent. Effectively, you're pinned to the bottom. There's a buoyancy calculator spreadsheet over on the Equipment -> BCs ... forum. It is interesting to play with.

I'll probably just avoid the tanks, in the winter I should be able to get the gear I want easily enough, and the next possible time I'd be back in Seattle in the summer (2 summers from now) I'll probably be ready to buy my own tanks.

However, I can't say I'd necessarily agree with making all your diving less enjoyable to help in an emergency situation which is pretty unlikely to start with and that probably has other solutions. I personally have trouble seeing a tank being so heavy that after ditching any removable weight you can't kick yourself to the surface with fins, but even in this situation, can't you just hook arms with your buddy and go up together (the chances of double catastrophic BCD failure seem remote).

If you are using 40# of weight, you absolutely do not want to put all of this in the BCD weight pockets for all the reasons we have been discussing throughout this thread.

First, your pack will weigh nearly 80#. Second, if you drop a pocket, no power on earth will keep you from rocketing to the surface.

Consider splitting the weights between a harness and the BC. Put as much weight in the harness as you can consistent with being buoyant at the surface in your wetsuit but without your BC. This way, if you need to adjust your BC or reattach the tank that is falling off, you can float without the BC.

Put the rest of the weight in the BC consistent with the fact that the BC must have enough lift to support the weights, the tank, the regulator and any other equipment tied to the BC. It is important that the BC be capable of supporting itself on the surface without the buoyancy of the diver in a wetsuit.

Oh ya, I may have not been clear, I don't want all the weight integrated, I'm just saying I don't want to have a 40 pound weight belt. Preferably 20lbs integrated and the rest on the belt.

This cold water diving takes a lot more thought than warm water diving where you can just toss 6# in the weight pockets, grab an Al 80 and start making bubbles.

I really need to try this warm water diving some time

 

[rstofer]

However, I can't say I'd necessarily agree with making all your diving less enjoyable to help in an emergency situation which is pretty unlikely to start with and that probably has other solutions. I personally have trouble seeing a tank being so heavy that after ditching any removable weight you can't kick yourself to the surface with fins, but even in this situation, can't you just hook arms with your buddy and go up together (the chances of double catastrophic BCD failure seem remote).

You need to look at the numbers. For the given scenario, your buddy's lift capacity may not be adequate to lift both of you. The same situation that, theoretically, has you pinned to the bottom also requires maximum lift from your buddy, assuming equivalent configurations.

Can a diver swim off the bottom with 16# of weight? Beats me... With a 6# contribution from your buddy's flotation you would each need to lift 5#. That should be no problem. Both conscious, both kicking, no problem.

The problem is, your buddy should never be your backup plan. Take a lift bag or a DSMB with adequate lift. You absolutely want the ability to self-rescue.

The reason I bring this up is that I have (2) HP 100s, (2) Al 80s and (2) Al 50s. I need two more tanks (4 divers) but I'm torn between the higher priced and highly negative steel tanks or additional Al 80s.

Richard

 

[diver 85]

"- all your weight in one place: take off your BC and your flying! Or would this be different at depth so one's positive buoyancy wouldn't be so problematic?"...........



One of the reasons I have worn a weight belt on every dive I have ever made......Why fix something if it 'ain't broken' is my motto....

 

[rstofer]

"- all your weight in one place: take off your BC and your flying! Or would this be different at depth so one's positive buoyancy wouldn't be so problematic?"...........



One of the reasons I have worn a weight belt on every dive I have ever made......Why fix something if it 'ain't broken' is my motto....

At depth, the wetsuit is considerably less buoyant. At greater depth it is even less so. But it is never negative so even if it produces only a few pounds of lift, you still have to counteract it. And it gets more buoyant as you ascend. At some point you will not be able to overcome the buoyancy without ballast.

Weight belts work well while you still have hips. I don't; a harness works for me!

Richard

 

[rstofer]

At depth, the wetsuit is considerably less buoyant. At greater depth it is even less so. But it is never negative so even if it produces only a few pounds of lift, you still have to counteract it. And it gets more buoyant as you ascend. At some point you will not be able to overcome the buoyancy without ballast.

Weight belts work well while you still have hips. I don't; a harness works for me!

Richard

I wonder if there is a condition under which a wetsuit is compressed to the extent that it is negative. I suppose it could be possible.

Richard

 

[Coldwater_Canuck]

You need to look at the numbers. For the given scenario, your buddy's lift capacity may not be adequate to lift both of you. The same situation that, theoretically, has you pinned to the bottom also requires maximum lift from your buddy, assuming equivalent configurations.

Can a diver swim off the bottom with 16# of weight? Beats me... With a 6# contribution from your buddy's flotation you would each need to lift 5#. That should be no problem. Both conscious, both kicking, no problem.

The problem is, your buddy should never be your backup plan. Take a lift bag or a DSMB with adequate lift. You absolutely want the ability to self-rescue.

The reason I bring this up is that I have (2) HP 100s, (2) Al 80s and (2) Al 50s. I need two more tanks (4 divers) but I'm torn between the higher priced and highly negative steel tanks or additional Al 80s.

Richard

The problem with the numbers is we're not entirely sure what the values would be. I just see it difficult to believe that the tank's weight alone would make it so you couldn't kick to the surface in the first place, and also that one person's BCD with both people kicking as hard as they could wouldn't be enough to get both to the surface. There's obviously numbers you can plug in where this won't be the case: but are those numbers relistic (in particular: figuring out how much weight you can get to the surface with your fins is difficult to know).

And even if this did happen, there's other options. Switch to your pony and then hold down the purge on your main tank: getting the air out may well be enough. In the worst case, you could always take the BCD and tank off, and just use your pony to surface (of course you'd need to be careful you still have a weight belt or something so you can control your ascent - and you may never see the tank and BCD again). I guess I'm just saying I see it difficult to believe that there'd ever be a situation that I couldn't get out of where an aluminum tank would have made the difference. I get what you're saying, just not sure if it would actually come up.