dropping weights

[MikeFerrara]

Angie S once bubbled...



Then, when the *new* textbook came out toward the end of our class, there was barely a mention in it about SAC rate, and certainly nothing about a time calculator. I am so glad that I got the "old" materials and the information about planning air consumption. Is the assumption now that everyone should have a dive computer? I haven't saved enough money yet for my own BC and regs, much less a computer. So I guess I'll be the slow one on the boat, sitting there with my antique planning slate!

Have a good weekend, everyone!
Angie

I'm an instructor for two agencies and I don't know what assumptions their making. Not all dive computers are air integrated so I don't think that's it. I think they just hope your shallow enough that the ascent doesn't use a significant amount of gas. Maybe they assume you'll be diving under supervision and someone else (DM?) will look out for you. But guess what...PADI dive masters aren't taught squat about gas management either. IANTD goes into it a little further at the OW level. Like many other things they seem to think OW is too soon to teach it but they don't include it in the other classes either. Like trim, most agencies don't even mention it in the OW course. Funny though it's also missing from the AOW materials and rescue and DM and the Instructor development course. To be honest I have given up trying to make sense of the logic and do what I think I should (in compliance of standards of course).

 

[Zept]

Rick Murchison said...
And while I can't think of a case offhand where it would be a bad idea to drop 'em with an emergency on the surface, I suppose there are some.

I vaguely remember a report of an incident in which a rescuer brought a victim to the surface. Rescuer ditched his/her own weights before getting the victim buoyant, the victim sank, and the rescuer was unable to get off the surface and go after them. Victim drowned.

Zept

 

[Norda]

Angie,

While it may seem slow, you will be better off doing the manual computations and I'm glad to hear your taking the dive planning seriously. While the computer is easy and will give you more dive time, nothing substitutes for learning the "manual" way.

BTW, when you feel like your ready for the next step in learning, do a search on this board for SAC & SCR and do some research. I also took the SSI course and it took me a while to figure out what people on this board were using when they quoted rates of .21 and .30, etc, when my SAC rates were in the teens and twenties.

Bill.

 

[FallenMatt]

I just switched from standard jacket bc (integrated weights) to backplate and wings and i was just thinking about the whole ditchable weight thingy.

With backplate, harness and crotch strap there is no way to quickly ditch your weights (maybe i am approaching it in a wrong way) because your weight belt will get stuck on the crotch strap. you have to open your waist belt, take it out from crotch strap loop, get the weight belt, drop weight belt...

but that's besides the point. I used to read Rodale's scuba magazine articles about scuba accidents and analysis of them (i think it is a monthly thing in there).. almost every second article would point out "remember to ditch your weights when having problems" and pointing to all different occasions when not ditching weights killed the diver...

Then i've spent last week reading "Last Dive", "Deep Descent" and "caverns measurless to man"... and saw there few extreme examples of deaths due to not being able to ditch the weights. Like a diver with very heavy steel tank setup forgets to open its air valves and not being able to inflate the wings drops right to 280 feet (Andrea Doria wreck) and dies.

Granted rec diver is not going to dive in a place with "no bottom" so it should not be a problem.. you will stop at that 60 feet and you will have time to figure this out....

So all those situations when you have punctured wing/BC or forgot to open the tank valve or your LP inflator hose is messed up .. that would be a good idea to drop the weights....

On a flip side dropping weights inside a cave would make you pined to the ceiling and immobilized... which pretty much means death if you have any kind of trouble... (i guess this is true for a wreck penetration too)

Maybe they (cert agencies) recomend ditching weights because for a beginer diver being @ 40 feet going up uncotrollably _IS_ better than drowning ?

And finally.. with my new backplate setup i have only total of 4lb on my weight belt.. that's with two piece 3mm wet suit, 80 alu tank @ 500 psi and being at 10 feet depth.
I can imagine that even if i would ditch that 4 lb i would still be able to control my ascent or even swim down against it...

oh well.. it is after 1 am .. i gotta sleep and not type longish posts

 

[detroit diver]

FallenMatt once bubbled...
.......

Granted rec diver is not going to dive in a place with "no bottom" so it should not be a problem.. you will stop at that 60 feet and you will have time to figure this out....
......

Slightly off topic, but this is one of the reasons that we practice valve drills. If you have forgotten to open your valve, and are sinking rapidly, I think you would want to know that you could reach back and just turn it on before you hit 60 feet!

 

[MikeFerrara]

FallenMatt once bubbled...

but that's besides the point. I used to read Rodale's scuba magazine articles about scuba accidents and analysis of them (i think it is a monthly thing in there).. almost every second article would point out "remember to ditch your weights when having problems" and pointing to all different occasions when not ditching weights killed the diver...

One of the problems with that magazine...

I remember some of the articles. They pointed out how many divers were found dead with their weights in place. They were found with other things in place also. They presented no argument that having weights in place had anything to do with the death. I remember arguing with DM's and instructors about it also. I'll bet they killed more divers by convinccing them to drop their weights at depth.

Reference the DAN report...Buoyancy control problems and rapid ascent to figure promenantly in dive injuries.

IMO, Rodales would serve divers best if they just shut up or at least go out and learn something about diving before saying anymore.

 

[Dryglove]

MikeFerrara once bubbled...
IMO, Rodales would serve divers best if they just shut up or at least go out and learn something about diving before saying anymore.

He he.......ya think?

 

[FallenMatt]

MikeFerrara once bubbled...

I remember some of the articles. They pointed out how many divers were found dead with their weights in place. They were found with other things in place also. They presented no argument that having weights in place had anything to do with the death.

That reminds me about something slightly off-topic... (i think from "deep descent" or "last dive".. i could find the relevant quote)..

after finding dead diver at depth the rescuers inflate the bc and send the body to the surface while they go back slowly doing their deco stops.

Back on land the doctor puts cause of death as "air enbolism". Well obviously even in a dead body during rapid ascent the gasses explode the lungs but that wasn't the cause of death.

I wonder.. how relevant are the analysis of diving eccidents done by the people who don't dive or know little about it? And how often such analysis and people who made decisions based on it mess up ? give bad advice ?

 

[FallenMatt]

Just after posting last message i started reading manual of my MC/Wing... here, on page 4:

"In an emergency such as an out of air situation or uncontrolled descent, it is important to remove and jettison weight immidiatelly. DO NOT depend solely on using your MC's power inflator to lift you to the surface." (original emhasis)

This is the manual for Halcyon MC+ Pioneer wing.

Putting aside all the usual comments about proper air management and doing valve skills:
Obviously when you are out of air you probably also can't power-inflate your wing to take you back to the surface...

 

[MikeFerrara]

FallenMatt once bubbled...


I wonder.. how relevant are the analysis of diving eccidents done by the people who don't dive or know little about it? And how often such analysis and people who made decisions based on it mess up ? give bad advice ?

The cause of death is almost always drowning and or embolism. They might be right but what we need to know is the cause for the drowning or embolism and the folks who write up the death cert don't care about that.