Equipment Trends: The BCD

[MXGratefulDiver]

Close. Warm water but back inflate BC.

i guess I don't get the concept of how sidemount can save your back on land which is supposed to be a benefit over a traditional BC. Take the example John uses. You carry your tank/tanks down to the water, wade out, grab the tanks and clip them on. Couldn't the very same thing be done with a standard BC. Carry the tank down to the waters edge, strap it to your BC, float it out waist deep, put on the BC. The final result seems to be the same with no strain on your back.

There are options ...

- two trips, one tank at a time
- there are places where you can move your tanks to the water's edge on a dolly
- or a nice dive buddy can help you get them down there

In all cases there are trade-offs ... like most things. But it's nice to have options ...

... Bob (Grateful Diver)

 

[Locus]

This is anecdotal, but of my three friends who are newly-minted DM's, one started in a bp/w, the other two switched one at a time, and none of them has changed back to a jacket.

A newer diver recently remarked to me that "People who use a backplate dive differently", but personally I think that they're just different tools for the same job. One is just much more versatile and configurable.

 

[Eric Sedletzky]

I am curious, when you dive without a BC what is your tank / exposure protection combination?

It 's really easy to figure out.
The first thing I do is freedive with the suit combo I plan to use, or at least figure a rough idea of how much weight it will take to make that particular suit work based on experience of similar suits.
For instance, I have a 7mm two piece Yazbeck freediving suit I just started using to do shallowish scuba dives in because it's warm and flexible.
When I freedive in that suit I know I need 22 lbs. of weight to make that suit neutral at 25 feet.
So basically any additional ballast like plate, steel tank, etc. comes off the belt to keep that same 22 lbs total. So a 5 lb plate and a steel 72, I would take maybe 10 lbs off the belt and I know I will break neutral at about 25 feet maybe slightly less. The bigger and heavier the tanks I just find out the buoyancy characteristic of that particular tank plus the weight of the air and subtract it off the weight belt. One thing people don't think about is that when you freedive you have a packed lung full of air that you don't exhale at depth, and with scuba you are constantly breathing, so you have to figure that in. The other thing is the buoyancy of the suit changes with time spent at depth both in the constant pressure crushing the suit plus the drop in temperature of the suit which makes the bubbles smaller reducing the buoyancy. So this actually makes up for the lightening up of the tank as you use air. Suits don't recompress as fast as it takes a diver to resurface even with a stop.
Typically I like getting a little light at about 18 to 20 feet at the end of the dive. A lot of times I'm dragging around game so that can offset being light. The other thing I sometimes do is find a rock to hang onto and sit at 15 for a few then drop the rock and go up. Or I grab a kelp stalk and hold myself with that. It's all kind of instinctive and you make use out of what you have, around you, that's part of the fun of it. My depths and times are shallow and short enough with backpack diving that I could come straight up without a stop if I wanted. The final and last safety protocol is to simply dump your belt and go up, just like freediving.

Simply put, backpack diving is like freediving but you can breath underwater. All the same weighting, finning techniques, the same gear (except for the S.C.U.B.A.). It's like you took a freediver and stuck a tank on them, (and lightened up the weightbelt a little).

 

[cool_hardware52]

It's well to remember that the early days of scuba were accomplished without BC's. Of course the early scuba divers were drawn from the ranks of skin divers. Fit, well acquainted with the sea, and comfortable in this environment. Some how we survived.

Having said that there wasn't much hovering going on, and the available tanks were modestly sized, repurposed fire bottles or 2250 72's The fact remains however that bc's have become ridiculously huge, and are too often used an equipment "bandaid" for inadequate education about buoyancy and weighting.

Tobin

 

[Rich Keller]

i guess I don't get the concept of how sidemount can save your back on land which is supposed to be a benefit over a traditional BC. Take the example John uses. You carry your tank/tanks down to the water, wade out, grab the tanks and clip them on. Couldn't the very same thing be done with a standard BC. Carry the tank down to the waters edge, strap it to your BC, float it out waist deep, put on the BC. The final result seems to be the same with no strain on your back.

Another option would be to leave the tank on the surface and dive with an umbilical instead. It takes some getting used to but greatly reduces the stress on your back. I do this diving from a kayak so the tank follows me but there are other products on the market that do the same thing.

 

[danvolker]

[video=youtube_share;75VberZ2NkU]http://youtu.be/75VberZ2NkU[/video]

For real scuba divers, this can make sense to maybe 65 feet deep or so..but at some point, the length of the umbilical becomes drag....so high current dives like we have in Palm Beach don't make sense much deeper than 65 or so feet.....Brownies has also been developing a fiber optic link to the surface for gps, tank pressure and more..


Divers using this "learn" to go up or down by "SWIMMING", and they learn to figure ideal weighting....Wetsuit choice means deciding how light you want to be when you want to swim down, to be pretty neutral at the planned bottom depth....there is no "tank swing".

 

[Bob DBF]

Simply put, backpack diving is like freediving but you can breath underwater. All the same weighting, finning techniques, the same gear (except for the S.C.U.B.A.). It's like you took a freediver and stuck a tank on them, (and lightened up the weightbelt a little).

When I started SCUBA diving, freediving included SCUBA diving because you were not in a hard hat hooked by hose to a boat for air. Since then freediving dropped any attached air and SCUBA has become the word Scuba. Times do change.

Most of the time you can spot freedivers when they are on SCUBA because, aside from possibly having freedive fins, they continue to use freediving techniques when SCUBA diving, mostly because it is more efficient and habitual.


Bob
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Originally Posted by AfterDark
I'm in a very elite class of divers. OBDs - Old Bold Divers.

There aren't many of us which is why we're elite. We started diving when it was in some parts of the country a self taught sport. We used double hose regs no BCDs, SPGs, or PDCs. Our wet suits had no lining, we used talc to get into them. We checked our tank with a pressure gauge before we mounted our reg and made sure our J valves were in the up position. We weighted ourselves to our target depths and sometimes had a hell'va time swimming to the bottom. We used Navy dive tables for air because nothing else was available, and we used air because that's all there was to breath no matter what depth the dive. We saw our friends die from mistakes we didn't know could be made until their deaths showed us what not to do. We are in a class by ourselves. No cert or plastic card, only time, diving and luck gets you there.

 

[boulderjohn]

When I started SCUBA diving, freediving included SCUBA diving because you were not in a hard hat hooked by hose to a boat for air. Since then freediving dropped any attached air and SCUBA has become the word Scuba. Times do change.

Scuba means Self Contained Underwater Breathing Apparatus, doesn't it? How would a free diver be part of an group whose name requires a self contained underwater breathing apparatus?

I know the term skin diving used to refer to both free diving and scuba, but I have never heard that scuba included free diving under the umbrella of its definition.

 

[dumpsterDiver]

Scuba means Self Contained Underwater Breathing Apparatus, doesn't it? How would a free diver be part of an group whose name requires a self contained underwater breathing apparatus?

I know the term skin diving used to refer to both free diving and scuba, but I have never heard that scuba included free diving under the umbrella of its definition.

I thought he explained the derivation of the terms well enough. His reference to freedivers looking different than "scuba" divers (when scuba diving) resonates with me. He did not really explain what he means, but I suspect that he observes that they tend to never do feet first descents and will do a duck dive and power down with the fins head first ,, things like that...

Also, with respect to the trends in BS's... Are we starting to see a movement away from the one piece BP/W harness with no clips or adjustability? It seems like that is becoming more prevalent to me.

Recently, I modified my one piece harness to include belt slides on the waist strap, which allows me to open up and tighten the shoulder straps in an instant. I've not quite perfected my latest experiment because the weather has been bad lately, but I think it is the way to go (for me).

 

[Bob DBF]

Scuba means Self Contained Underwater Breathing Apparatus, doesn't it? How would a free diver be part of an group whose name requires a self contained underwater breathing apparatus?

I know the term skin diving used to refer to both free diving and scuba, but I have never heard that scuba included free diving under the umbrella of its definition.

Back in the 50's & 60's skindiving and freediving were interchangeable and differentiated that diving from Hard hat and suit, or attached, diving that was the norm. Snorkeling was more the term used for freedivers at the time since it gave the method of air supply as did specifying SCUBA divers if you wanted to differentiate them. Now the term snorkeling is used to designate people that mostly stay on the surface and breathe through a snorkel, and freedivers can now mean a competitive group setting depth records. Language and usage change, not to mention how local dialects, going away quickly now do to mass media, may mean the usage in area of the country might be different than another back then.

Since I was snorkeling (freediving) in the late '50's and SCUBA in the early '60's, I heard and used the terms back then and communication was not a problem that it seems to be now. I must admit the term crazy and SCUBA diving were synonymous at that time.

It is kind of like the term Tech divers. The word was made up in the '90's and specified a particular type of recreational diving. To hear some talk now you would think it is another type of diving altogether, and overlooks the fact that recreational divers have been doing that type of diving for decades before the name was applied. Most divers have no interest in the history of diving, and have no idea what diving was like before the date they started OW class.



Bob
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Trained when J-valves solved the OOA problem. Sometimes.