Dive Planning & VR3

[Mark Chase]

Originally Posted by [b

Quote[/b] ]I use a Vytec in gauge mode. It's an excellent tool for running deco and is all that is required for even the most advanced trimix dives (with proper training). The resetable stopwatch feature is indespensible. Avoid AI!

Regards,

Mark.

Having nicked this quote of another thread I have a question. Last week on a couple of deeeeeep dives we flew the VR3 and saved a masive 30mins deco on one where the dive didnt match the plan for logistical reasions. On the 102m dive I decended to max depth before Andrew and was there fractionaly longer and I racked up an aditional 6mins deco for my additional 1min at max depth ? Fortunatly the VR3 kept tabs on every move we made.

So my question is how do you do exploritory dives without a tool like the VR3. DIR is all about Cave's so if you want to push another 1000m into a deep cave complex how do you plan it. You have little or no idea what dephs you will be faced with or how long the travers of the cave will take.

Even on a 'normal' cave dive how would you plan or cope with a lost line serch at say 80m where deco is racking up at a masive rate.

Not slagging just curious

Mark Chase

[Bob Cooper]

Originally Posted by [b

Quote[/b] (Mark Chase @ Jan. 08 2004,18:17)]

Originally Posted by [b

Quote[/b] ]So my question is how do you do exploritory dives without a tool like the VR3. DIR is all about Cave's so if you want to push another 1000m into a deep cave complex how do you plan it. You have little or no idea what dephs you will be faced with or how long the travers of the cave will take.

Even on a 'normal' cave dive how would you plan or cope with a lost line serch at say 80m where deco is racking up at a masive rate.

Mark

You know better than to say "DIR is all about caves".  DIR works for all kinds of diving blah, blah, blah!

For a regular cave dive, you will "know" the depth, because it is fixed, so the dive plan is based on time only.  The dive is called on gas, time or comfort level etc.  I have a set of tables and I select the appropriate table for the depth we are diving.  So, lets imagine we dive a cave to a max depth of 30m, we might have a 20m table and a 30m table.  We will agree in advance when to call the dive (on terms of gas or time).  So when we get to our first deco stop we look at our tables and run a schedule based on depth and time. If our average depth was 20m we would run the 20m table.  It's quite often difficult to do set stops like in the ocean because of the profile of the cave so we agree what we will do in advance.  The cave profile dictates where the deco is done.

You can communicate what schedule to run with simple hand signals (i.e. a 60 min schedule or a 70 min schedule).

Pushing "an extra 1000m into a cave" is a bit ambitious!

As far as the lost line scenario goes.....If you are lost, off the line (probably in zero vis) at 80m and you've lost your team too, deco is the least of your worries!

Hope this helps.  Happy to discuss more but I don't have any experience of cave exploration.  I can only imagine how the deco is planned for this sort of dive.

Bob

[Alan57]

Mark
DDPlan by Gordon Henderson (free software) has a table function where you can print-off different depths and times which are then laminated. This gives you the various permutations in a handy laminated slate(s). It also can produce bailout tables. Not as elegant as the VR3.
Warning: I dive D'OH rather than DIR and avoid caves wherever possible.
Alan

[Mark Chase]

Originally Posted by [b

Quote[/b] (Bob Cooper @ Jan. 08 2004,20:50)]As far as the lost line scenario goes.....If you are lost, off the line (probably in zero vis) at 80m and you've lost your team too, deco is the least of your worries!

Hope this helps.  Happy to discuss more but I don't have any experience of cave exploration.  I can only imagine how the deco is planned for this sort of dive.

Bob

Originally Posted by [b

Quote[/b] ]You know better than to say "DIR is all about caves".  DIR works for all kinds of diving blah, blah, blah!

Sorry this wasnt intended as an insult. The point was you can usualy get a depth on an OW dive with a simple echo sounder but if your exploring an undived cave  how would you know what the depths are? The next tunnel might plumet down to 200m or lead up to 20m???

Originally Posted by [b

Quote[/b] ]For a regular cave dive, you will "know" the depth, because it is fixed, so the dive plan is based on time only.  The dive is called on gas, time or comfort level etc.  I have a set of tables and I select the appropriate table for the depth we are diving.  So, lets imagine we dive a cave to a max depth of 30m, we might have a 20m table and a 30m table.

Yes this is OK for a cave that has been explored by other divers and where the details of their explorations are known but I am talking about a virgen site. Surley you would need a shead load of tables to cope with the possable permitations of the dive.

Originally Posted by [b

Quote[/b] ]Pushing "an extra 1000m into a cave" is a bit ambitious!

This just displays my ignorance of cave diving 1000m dosent sound like a lot.

Originally Posted by [b

Quote[/b] ]As far as the lost line scenario goes.....If you are lost, off the line (probably in zero vis) at 80m and you've lost your team too, deco is the least of your worries!

Yes I apreciate its a bad place to be, but have you read the Snoopyloop site dive reports. He lost the line a couple of times so it obviously does hapen. If it did and you had enough gas to get out does the DIR deco on the fly give a viable option for getting out safley?


Again I stress this is just for discussion I dont want a ruck.


ATB

Mark Chase

[db8us]

Originally Posted by [b

Quote[/b] (Mark Chase @ Jan. 09 2004,00:32)]

Sorry this wasnt intended as an insult. The point was you can usualy get a depth on an OW dive with a simple echo sounder but if your exploring an undived cave  how would you know what the depths are? The next tunnel might plumet down to 200m or lead up to 20m???

Yes this is OK for a cave that has been explored by other divers and where the details of their explorations are known but I am talking about a virgen site. Surley you would need a shead load of tables to cope with the possable permitations of the dive.

This just displays my ignorance of cave diving 1000m dosent sound like a lot.

Yes I apreciate its a bad place to be, but have you read the Snoopyloop site dive reports. He lost the line a couple of times so it obviously does hapen. If it did and you had enough gas to get out does the DIR deco on the fly give a viable option for getting out safley?


Again I stress this is just for discussion I dont want a ruck.


ATB

Mark Chase

Originally Posted by [b

Quote[/b] ]
This just displays my ignorance of cave diving 1000m dosent sound like a lot.

It is "just" another 2hours of bottom-time :-)

[Mark Chase]

Originally Posted by [b

Quote[/b] (db8us @ Jan. 12 2004,12:44)]

It is "just" another 2hours of bottom-time :-)

There you go see, no problem at all

OK perhaps that should have been 100m. My vast knowledge of deep cave exploration is limited to Billingshurst cave in Gozo. That took about 15mins to get to the end of it

Sorry, with scooters and the like being used I really thought 1000m was no big deal but I was obviously way off.

Hey De8us have you had a look at the Snoopyloop site? What did you think?

ATB

Mark Chase

[Bob Cooper]

Originally Posted by [b

Quote[/b] (Mark Chase @ Jan. 12 2004,15:26)]

Originally Posted by [b

Quote[/b] ]Sorry, with scooters and the like being used I really thought 1000m was no big deal but I was obviously way off.

As a rule of thumb, you can generally reckon on about 10-15m/min swimming (no flow) and about five times that when scootering.

Bob

[wreckweasel]

Pah bob.... I saw you on the illinois..... round and round in ickle swircles

Its that OC stuff, appalling for your sense of direction  

[db8us]

Originally Posted by [b

Quote[/b] (Mark Chase @ Jan. 12 2004,16:26)]Hey De8us have you had a look at the Snoopyloop site? What did you think?

I think they did a great job with a different approach.

Michael