SAC rate question

[DA Aquamaster]

I have a low average of about .34, and a high average of maybe .42. I'd say a hoover would be anyone who cut someone elses dive short by a significant amount.

That definition is too inconsistent with too many confounding variables.

By that definition when I dive doubles, everyone else with a single tank in the group would be a hoover (ie. hoover status would depend on equipment as well as air consumption.)

Similarly, if there is one diver in the group with exceptionally low gas consumption, every other diver in the group with good to average gas consumption would be a hoover. (ie. everyone other than the 90lb female tri-athlete on board would be a hoover.)

That definition is also too subjective. Anyone who upsets us by ending a dive early becomes a "hoover". We should just round it off nicely and call them a "stroke" too while we are at it. The risk of being called something derogatory sets up some unhealthy psychological factors that in turn lead to other far more serious problems.

The numbers game consequently gets very problematic if we set the hoover bar too low. We end up with a whole bunch of divers wanting to avoid being called Hoovers or at the other extreme wanting to gain chest thumping, bragging, call other people hoover rights by consciously trying to limit their breathing to meet a mythical .4 RMV with consequent CO2 buildup, headaches, increased narcosis, greater susceptibility to an O2 hit etc. And if they still come up short, they may be tempted cut into their reserve rather than be first to call a dive.

So personally, I'd prefer my buddy just breathe normally and demonstrate a SAC of .6 or even .8 and not cause me other potential problems on a slightly longer dive. As a general rule, I do not discuss excessive gas consumption with dive buddies unless they have truly excessive consumption or they are expressing interest in improving gas consumption and are doing things in the water that increase their consumption.

Finally, in my experience, accomplished divers with RMV's around .6 are pretty much in the normal range for real world swimming intensive cold water dives.

 

[Damselfish]

That definition is too inconsistent with too many confounding variables.

By that definition when I dive doubles, everyone else with a single tank in the group would be a hoover (ie. hoover status would depend on equipment as well as air consumption.)

Similarly, if there is one diver in the group with exceptionally low gas consumption, every other diver in the group with good to average gas consumption would be a hoover. (ie. everyone other than the 90lb female tri-athlete on board would be a hoover.)

That definition is also too subjective. Anyone who upsets us by ending a dive early becomes a "hoover". We should just round it off nicely and call them a "stroke" too while we are at it. The risk of being called something derogatory sets up some unhealthy psychological factors that in turn lead to other far more serious problems.

The numbers game consequently gets very problematic if we set the hoover bar too low. We end up with a whole bunch of divers wanting to avoid being called Hoovers or at the other extreme wanting to gain chest thumping, bragging, call other people hoover rights by consciously trying to limit their breathing to meet a mythical .4 RMV with consequent CO2 buildup, headaches, increased narcosis, greater susceptibility to an O2 hit etc. And if they still come up short, they may be tempted cut into their reserve rather than be first to call a dive.

So personally, I'd prefer my buddy just breathe normally and demonstrate a SAC of .6 or even .8 and not cause me other potential problems on a slightly longer dive. As a general rule, I do not discuss excessive gas consumption with dive buddies unless they have truly excessive consumption or they are expressing interest in improving gas consumption and are doing things in the water that increase their consumption.

Finally, in my experience, accomplished divers with RMV's around .6 are pretty much in the normal range for real world swimming intensive cold water dives.

yeah, basically agree with this, but I think there was an implied "all else being equal in typical circumstances" implied in that definition.

 

[Charlie99]

That definition is also too subjective. Anyone who upsets us by ending a dive early becomes a "hoover". We should just round it off nicely and call them a "stroke" too while we are at it. The risk of being called something derogatory sets up some unhealthy psychological factors that in turn lead to other far more serious problems. .....

As a general rule, I do not discuss excessive gas consumption with dive buddies unless they have truly excessive consumption or they are expressing interest in improving gas consumption and are doing things in the water that increase their consumption.

Finally, in my experience, accomplished divers with RMV's around .6 are pretty much in the normal range for real world swimming intensive cold water dives.

On the typical warm water resort boat, 0.6cfm SAC might even be better than average, and anything lower than 0.75cfm is reasonable.

High air consumption rate isn't in itself a problem. It is more often a symptom of some other problem, such as poor trim, doing the whole dive while negatively buoyant, or a high level of excitement or fear.

I strongly agree with DA Aquamaster's comments about the potential negative consequences of derogatory comments and a divers efforts to avoid them. In particular, I've seen a diver cut into his safety margins on air supply while trying to avoid being the first in a group to call the dive. I did strongly discuss that with the diver in question.

I don't have a precise definition of a hoover, but a person who gives another diver a hard time about their air consumption is an ________ (fill in any appropriate word that can't get past the board's auto-censor program)

Charlie

 

[Uncle Pug]

I don't have a precise definition of a hoover, but a person who gives another diver a hard time about their air consumption is an ________ (fill in any appropriate word that can't get past the board's auto-censor program)

Charlie

Sorry Charlie but I have to disagree with you here... at least with the implicit sentiment that hoovers have the right to hoover without remonstration from anyone else... and the explicit sentiment that anyone who does complain about the hoover's hooverliness is a bad person.

I also disagree with the notion that hoovers need not be concerned with their hooverliness. They should be concerned. Hooverliness is often an indication of other problems that need to be corrected but even taken by itself hoovering your gas supply is an unsafe way to dive.

Now a lot of the psycho/social problems of addressing hooverliness hinge on defining what constitutes hoovering. To answer the original poster's question directly, "No, you are not a hoover with that rate of consumption."

Hoovering is going through your gas supply at an un-necessary and abnormally high rate under normal dive circumstances.

 

[The Kraken]

Do you think The Grinch will steal all of the regulators from Little Cindy Hoover and Hooverville this Christmas ? ? ? ? :evilsmile