DPV Diver

[jdobbertien]

For those who are DPV certified what are you thoughts? Do you feel the cost was worth it to take the class and get a scooter. I'm not saying should I take the class before I scooter in a cave; to me that's not a question. I primarily dive high flow caves that allow scooters and it's something I've wanted to do for awhile. Has scootering taken your diving to new levels which can justify the cost? How often do you scooter and if you could do it again would you?

[Kelly Jessop]

For those who are DPV certified what are you thoughts? Do you feel the cost was worth it to take the class and get a scooter. I'm not saying should I take the class before I scooter in a cave; to me that's not a question. I primarily dive high flow caves that allow scooters and it's something I've wanted to do for awhile. Has scootering taken your diving to new levels which can justify the cost? How often do you scooter and if you could do it again would you?

#1 I qualified to be grand fathered in since I got my Abe Davis before 1997,but I did take the class, and learned a tremendous amount. I don't know what a scooter class costs now,but my money was well spent
#2 A scooter allowed my to extend progressive penetration. Where some passages I would swim repetitively having seen it quite thoroughly in the past, it would allow me to skip this. Also, a scooter became a tool to facilitate survey work to get to the destination and save more time for the job at hand.
#3 I barely scooter once or twice a year,mainly because the type of diving I do doesn't necessitate it. Even when I go to high flow places now I prefer not to scooter because I like to task my ability to read the cave and flow patterns, and maintain swimming skills in different conditions.

[floridabob]

#3 I barely scooter once or twice a year,mainly because the type of diving I do doesn't necessitate it. Even when I go to high flow places now I prefer not to scooter because I like to task my ability to read the cave and flow patterns, and maintain swimming skills in different conditions.

Hilarious.

But the questions seem to be: is a scooter & class worth it; would you do it again; has it taken your diving to another level.

Yes, the class is worth it when its done well.
Yes, I would choose scootering again and take the class.
Yes, it enables dives that could not be done otherwise.

Lastly, its fun.

Bob

[Kelly Jessop]

Hilarious.

Glad that I can entertain you,but the OP question was, "How often do you scooter?", and even makes a reference to justify the cost. Good question, why invest megabucks in a something that will collect dust and take up floor space.

[Rhino]

Glad that I can entertain you,but the OP question was, "How often do you scooter?", and even makes a reference to justify the cost. Good question, why invest megabucks in a something that will collect dust and take up floor space.

Echoing Victor, and the practice of a buddy of mine, you don't absolutely have to buy a scooter to make a scooter class worthwhile or enjoy benefits of scootering. Frankly, I never thought to ask my buddy whether he thought his class was worthwhile. He just seems glad to take any opportunity to rent, even for just one dive, like the river cave we scootered to last time.

[floridabob]

Glad that I can entertain you,but the OP question was, "How often do you scooter?", and even makes a reference to justify the cost. Good question, why invest megabucks in a something that will collect dust and take up floor space.

You almost always make me laugh out-loud.

I use my scooter with a purpose quite regularly. Both of them. I am not the one that has invested unwisely....which was part of my guffaw. The other part was the premise of your predive thought "I cant wait to task my ability and pick the optimum route with which to count these crayfish in an otherwise inaccessible system..."

Yep. Funny. Not a personal attack, just what bounced into my head.

Oops. I have my retirement squandered away into dive gear. That seems the epitome of unwise. But not unused, at least.

There are dives that a scooter is an absolute must, not just a tool to make the dive less taxing.

To each his own,
Bob

[Kelly Jessop]

The other part was the premise of your predive thought "I cant wait to task my ability and pick the optimum route with which to count these crayfish in an otherwise inaccessible system..."

I can appreciate your rationale. Do I like to scooter, yeah it can be fun,just like I enjoy taking my motorcycle for a spin. Since a majority of my diving is research based, and looking at species, carrying an oversized food processor blades near imperiled species is a little counter intuitive.

[Nitrogenius]

Yes, it enables dives that could not be done otherwise.

Hi Bob,


would you care to elaborate a little bit on that?
As I have been taught you would have to be able to safely finnish a dive with the scooter not working, no matter what. This means you have to bring gas with reserve to exit + enough deco gas to safely exit with the extended time spent at depth..
So the only advantage I can see is the savings of bottom time and thus a slighter less deco obligation on the way into the cave..
Or am I overseeing something here?


Regards,
Frank

[nakatomi]

Frank, maybe this example helps?

When scootering at Jackson Blue, I can get to at least about 3300' (Source Nouveau jump) using just thirds on one stage.
If max penetration for that dive would be 4000', at 50fpm one would need 4000/50=80 minutes to swim out
Assuming a SAC rate of 0.5, 80 minutes x 0.5 x 3.7 ATM, one would require 148 cuft of gas to swim out.

Two cave filled 95s contain 259cuft of gas, add to that 53cuft left in the stage tank used to scooter in.
That gives you 312 cuft to work with, with 148 required to swim out.
I would be comfortable to have at least 1.5 times what I need to swim out, should the scooter fail.
So 222cuft would be my rock bottom turn pressure, which would equate to 3080psi in the 95s.
That would leave 3080psi in the main tanks, plus 2000psi in the stage to swim out.

If all goes well, I would then use 600psi in each LP95 (or 37cuft of gas) to swim to somewhere around 4000 and check out the passages.
With a SAC rate of 0.5, that would provide gas for a tour of 37 / 0.5 / 3.7 = 20 minutes.

Bringing a second stage or bigger main tanks, would greatly increase the time you have back in the cave. You could easily turn 20 minutes into 50 or 60 minutes.

To compare that to swimming, using one stage and LP95's, getting to the stop light (4th T) which is at around 2300' or 2400' on thirds would about as far as I would expect to swim right now.

[midway]

Frank, maybe this example helps? ...

I could be mistaken but your example, although valid as a DPV dive plan (ignoring deco gas planning), has fallacies when drawing conclusions compared to the swimming case:

... using one stage and LP95's, getting to the stop light (4th T) which is at around 2300' or 2400' on thirds would about as far as I would expect to swim right now.

In essence, you are comparing apples and oranges. In the DPV case, you calculate max penetration and turn pressure based on gas volume remaining to swim out, with redundancy (you used 1.5). In the non-DPV case, you apply the standard 1/3 rule. In high flow JB for which you performed the estimates, to make the comparison meaningful you would want to calculate non-DPV turn pressure at the point where the remaining gas allows you to swim back, with the same redundancy (say 1.5) as in the DPV case. Otherwise, all that you're stating is that (i) you're being overly conservative in gas planning when you're swimming JB -- assuming your DPV planning is considered safe (I have no problems with it) -- (ii) or your DPV planning is unsafe relative to your safety standards when only swimming at JB. You can't have it both ways.