Hey Hoover ~ Did you ruin someone's dive?

[JeffG]

Actually, you had my old recreational dive buddy on the last Toby trip where I met you. He said that you did great on the last day that you were there.

Yea...but the truth never stopped the Lawman from trolling

 

[jbd]

You can apply any which formula you want, you'll still need past dive data to work with.

So, a new diver will have to guess, based on the few dives he or she has already done. Don't expect a very accurate estimate though. Which is why a new diver should restrict himself to dives well within the NDL and with the option of a direct ascent until said diver has enough data to work with.

While it is true that with more input data (experience) you will have a more accurate assessment of SAC rate. This of course leaves student diver or a new diver with little information to work with, but, does it mean they shouldn't work with what they have?

In my OW courses I required a minimum of five scuba dives for certification. If the students calculate their SAC rate for each dive, they begin to get a feel for doing the calculations and they get an idea of what their SAC rate is. As they progress through the dives you can ask them to plan a deeper dive and see if the air suppply they are going to use will provide them enough air to dive the planned profile. By doing this during their training they begin to realize that the AL 80 that only lasts them 20 minutes at 30 feet isn't really going to do much for them on a 90 foot dive in Coz while they are on vacation. Better to put off the vacation to Coz until they have gained some experience and improved their SAC rate.

This lets the new diveer make informed decisions about their diving instead of just going along with the crowd and either cutting the dive short safely or in few cases I know of personnally completely running out of air around 100 feet down.

IMO rough knowledge is better than no knowledge.

 

[FatCat]

While it is true that with more input data (experience) you will have a more accurate assessment of SAC rate. This of course leaves student diver or a new diver with little information to work with, but, does it mean they shouldn't work with what they have?

In my OW courses I required a minimum of five scuba dives for certification. If the students calculate their SAC rate for each dive, they begin to get a feel for doing the calculations and they get an idea of what their SAC rate is. As they progress through the dives you can ask them to plan a deeper dive and see if the air suppply they are going to use will provide them enough air to dive the planned profile. By doing this during their training they begin to realize that the AL 80 that only lasts them 20 minutes at 30 feet isn't really going to do much for them on a 90 foot dive in Coz while they are on vacation. Better to put off the vacation to Coz until they have gained some experience and improved their SAC rate.

This lets the new diveer make informed decisions about their diving instead of just going along with the crowd and either cutting the dive short safely or in few cases I know of personnally completely running out of air around 100 feet down.

IMO rough knowledge is better than no knowledge.

The last is true.

But air consumption at depth is not a linear extrapolation of SAC. There are too many variables involved.

IMO, gauge monitoring - ie. gas managment - is a better option for new divers. They can compare this to SAC calculation for all I care, but as you so aptly stated: a rule of thumb is a rule of thumb, nothing more.

Those who think that SAC calcs are the alfa and omega of gas planning should rethink.

 

[jonnythan]

The last is true.

But air consumption at depth is not a linear extrapolation of SAC. There are too many variables involved.

IMO, gauge monitoring - ie. gas managment - is a better option for new divers. They can compare this to SAC calculation for all I care, but as you so aptly stated: a rule of thumb is a rule of thumb, nothing more.

Those who think that SAC calcs are the alfa and omega of gas planning should rethink.

It might not be the omega, but it's certainly the alpha.

I can't imagine how anyone could begin any gas plan without it, unless your idea of gas planning is "be on the boat with 500"

 

[Northeastwrecks]

This brings me to the nagging question, what happens if you and this Hoover are the odd man on the boat and you don't want to dive with him? What if DM insists, as happened to me in Coz a few years ago? How do you get out of it if he is all there is and you are not trained or have the proper equipment to solo dive?

The same thing I've said to operators who tried to hook me up with newbies who needed babysitting.

"Put me on the liability waivers, have the divers re-sign them and comp my dive. If you want me to work by taking care of newbies while I'm on vacation, your not going to get me to pay for the privilege."

If the person was a complete cluster, as well as a hoover, I'd thumb the dive and change operators. Fortunately, that has never happened.

 

[JimC]

SAC/RVM tell me if I have enough gas to bother getting on the boat. It estimates how long my gas supply should last but is essentialy usless once the dive starts.
Rock bottom tells me when I need to head back and is the gas management number I need in the water.

Both are (essential) parts of dive planing, both are completely separate items that have nothing to do with one and other.

 

[jonnythan]

SAC/RVM tell me if I have enough gas to bother getting on the boat. It estimates how long my gas supply should last but is essentialy usless once the dive starts.
Rock bottom tells me when I need to head back and is the gas management number I need in the water.

Both are (essential) parts of dive planing, both are completely separate items that have nothing to do with one and other.

And how do you get your Rock Bottom?

 

[wolf eel]

This is kinda like people who hate kids we all were one at some point so you must hate yourself. Like being a new diver everbody was one.
If you have to take care of a group however from a dive charter then you should be given a break on the cost and maybe a steak and a couple of beers. Or the op should have pre planned dives set out for new divers and older ones. With the right amount of DMs on board.

 

[JimC]

And how do you get your Rock Bottom?

It based on an unrealistically high gas consumption - not something you calculate based on YOUR sac rate. I should edit my original post.

 

[Kestrell]

I dive with the same buddy. I would be just as reluctant to dive with someone I don't know as I would be borrowing someone else's BC or reg. When I plan my dive I plan on who my buddy is as well. If my buddy can't dive then I'll thumb the dive before I even leave the house, unless I can subdtitute my buddy with someone I know and trust. Therefore I would not get paired up with a "Hoover", nor would I be someone else's "Hoover".

Good question though.