Average depth calculation

[Karen Cleveland]

That is what I do use (no not the wheel!!!!). I was just trying to figure out what value average depth informatio is in deco planning. None that I can see but you and others have suggested otherwise so I am hoping to learn something.

If you plan a dive to 240 ft because there is supposed to be something cool there, but when you get there you find you would rather spend time at the top of the 200ft pinnacle because there was just sand at 240ft, you would like to be able to adjust your deco for the shallower depth or the shorter time spent at 240ft . If you opt to adjust your deco you can use average depth to do it.

Or if you happen to be doing a cave dive that will require deco, you can use average depth to determine the deco plan....especially if youdive that particular cave often and know what the average depth is going to be.

Karen

 

[wedivebc]

If you plan a dive to 240 ft because there is supposed to be something cool there, but when you get there you find you would rather spend time at the top of the 200ft pinnacle because there was just sand at 240ft, you would like to be able to adjust your deco for the shallower depth or the shorter time spent at 240ft . If you opt to adjust your deco you can use average depth to do it.

Or if you happen to be doing a cave dive that will require deco, you can use average depth to determine the deco plan....especially if youdive that particular cave often and know what the average depth is going to be.

Karen

Sounds like a good way to get bent. There is not a linear relationship between depth and tissue saturation. You can't just assume average depth and dive tables for that. You have to account for each compartment and and each exposure. I am no math whiz and my math skills don't seem to improve underwater so I would be reluctant to change any dive plan underwater unless I had a really sure fire way of doing the calculation. Average depth is not going to work that way.

 

[jonnythan]

Sounds like a good way to get bent. There is not a linear relationship between depth and tissue saturation. You can't just assume average depth and dive tables for that. You have to account for each compartment and and each exposure. I am no math whiz and my math skills don't seem to improve underwater so I would be reluctant to change any dive plan underwater unless I had a really sure fire way of doing the calculation. Average depth is not going to work that way.

You're right.. which is why I suggested playing around with V-planner to see what *does* work

 

[wedivebc]

You're right.. which is why I suggested playing around with V-planner to see what *does* work

This may surprise you but I have done a few deco dives and have played with a couple of different deco programs beginning with Dr X and v-planner is my deco program of choice.
It still doesn't support your statement about using average depth to calculate deco

 

[Karen Cleveland]

Sounds like a good way to get bent. There is not a linear relationship between depth and tissue saturation. You can't just assume average depth and dive tables for that. You have to account for each compartment and and each exposure. I am no math whiz and my math skills don't seem to improve underwater so I would be reluctant to change any dive plan underwater unless I had a really sure fire way of doing the calculation. Average depth is not going to work that way.

If you don't understand it certainly don't use it. Seems to be working well for myself and MANY others for years.

 

[wedivebc]

If you don't understand it certainly don't use it. Seems to be working well for myself and MANY others for years.

As soon as someone gives me a sound explainatin I will consider what you guys are talking about.

 

[jonnythan]

This may surprise you but I have done a few deco dives and have played with a couple of different deco programs beginning with Dr X and v-planner is my deco program of choice.
It still doesn't support your statement about using average depth to calculate deco

I know you do a lot of deco diving and use these programs.

I mean run various multi-level profiles compared with an "averaged" profile for a limited depth range and see what you come up with.

 

[H2Andy]

...

 

[TwoBitTxn]

I have thought about posting this link as long as I have seen this thread. I have decided to post it.

A previous discussion

TwoBit

 

[boomx5]

As soon as someone gives me a sound explainatin I will consider what you guys are talking about.

Hi Dave,

Just as Karen said there are many people, myself included,who use depth averaging for multi-level dives. We find it works great if executed properly, but is not something someone should just jump in and do without training. There are many reef structures that we like to explore that are in the 200'+ range. However, the only way to dive them is with either a boat, or on scooters. Since we use scooters it takes us about 25-30 minutes (sometimes more) just to get where we're going. Then there's the time spent exploring, the trip back and the deco that must be completed. 5thd-x put a PDF out that gives a little bit of info on it, if you haven't downloaded it yet you may want to look into it.