Planning simple dives

[twistypencil]

Hi,

I'm not doing any tech diving, just OC rec with plain old air. I'm wanting to use a dive planner to plan some upcoming dives, and I've never used my dive computer or a dive planner like MultiDeco to do this. I've got a Perdix and I've looked at MultiDeco, but it all seems pretty oriented around multiple gas tech diving with deco stops and the like.

Is there a way I can do a simple plan on my Perdix, or in some dive software, doing 1-4 dives during the day on plain air, or is dive planning only for tech people and I should just pull out the trusty dive plan card and keep doing it the old fashioned way?

 

[Reku]

1. turn perdix on
1a. turn perdix into oc tech mode
2. go to DIVE SETUP
3. go to DIVE PLANNER
4. fill in required information (it uses your current active gases)
5. if there is deco it will show you - if not it shows NDL and total gas you'd use.

it can plan simple square profile dives. just like you'd want.

You should keep using your tables - the perdix doesn't really know what a group is although it has a tissue graph. It's going to be a whole lot easier for you to just use tables and calculate groups like you are used to.

You should however get to know all the different modes of your perdix and how they work and how to change settings in them - this will be very beneficial to you. Try using the OC tech mode for a dive or 2 and see how you like it - you can always go back to the rec mode if you want. You can also set different data to show up on the perdix in tech mode.

Overall regardless of the types of dives you will be doing - it's 100% worth it to learn your computer even if you don't use those features.

 

[rsingler]

Yes, you sure can, with both Multi Deco and your Perdix, using the DivePlan+ function.

The problem is in comparing the algorithm that each uses.

For example, the PADI tables allow you a single 30-min dive to 80' within NDLs.
But if you plug 80' x 29 min into Multi Deco with ZHLC-GF algorithm and Gradient Factors of 100/100, you still end up with a required deco stop of 40 sec at 10 feet.
Perdix will give you an answer based upon the Gradient Factor you have selected for your OC-Rec mode.

I might suggest you download Subsurface. This free program is a great way to graphically visualize your repetitive dives, and has a recreational mode that gets you closer to what you're doing with the tables.

I applaud your effort to see what sort of nitrogen load you are accumulating over a long day's diving. Keep in mind that unless you plug in some sort of multilevel dive in Subsurface, your actual nitrogen accumulation will almost always be less than a square profile dive. Which, of course, is why computers have been such an improvement in giving us longer bottom times.

Give Subsurface a try!

 

[twistypencil]

Yes, you sure can, with both Multi Deco and your Perdix, rising the DivePlan+ function.

I might suggest you download Subsurface. This free program is a great way to graphically visualize your repetitive dives, and has a recreational mode that gets you closer to what you're doing with the tables.

Give Subsurface a try!

Actually, I do have Subsurface! I only got a dive computer recently, so I've only managed to log two dives on it, and I've put those into Subsurface... but I didn't realize that Subsurface had a dive plan mode.

 

[twistypencil]

1. turn perdix on
1a. turn perdix into oc tech mode

I'm curious why you say to turn oc tech mode on? Does this enable things that aren't otherwise there?

I can get to the dive planner without turning it on.

Also, I'm just using Air, so what should my active gasses be set to?

 

[rsingler]

I think I said OC-Rec. Just leave things as they are, and enter gas of 21/00

Oops! That was the other poster.
Yeah, leave in Rec mode for your purposes

But you'll have more fun with Subsurface. Your Perdix will just show you completing your dive with or without a deco obligation, and then NDL times for a given surface interval. The graphics in Subsurface give a much nicer indication of how close you are coming to filling your nitrogen tank with a given dive profile.

 

[twistypencil]

It seems like planning on the Perdix only really lets me put in the bottom time and the time. Is this the deepest I will go and how long I will spend at that depth? Or is it how long I expect to spend on the dive in total? Also it asks for my RMV, which I have no idea what it is, especially because I do not have the air integration for the Perdix.

Subsurface's dive plan is nice, it lets me do multi-level things. Its too bad it doesn't work on mobile, I'd like to be able to do that on my tablet!

rsingler when you said, "The graphics in Subsurface give a much nicer indication of how close you are coming to filling your nitrogen tank with a given dive profile." what do you mean? I wont have any nitrogen tanks?

 

[rsingler]

I was speaking figuratively. I apologize.
When I referred to your nitrogen tank, I really meant seeing how much nitrogen you are putting into your body (YOUR nitrogen tank) before you incur a deco obligation.

 

[rsingler]

Plug 0.8 cu ft/min into your RMV.
Your mileage may vary

 

[Reku]

I'm curious why you say to turn oc tech mode on? Does this enable things that aren't otherwise there?

I can get to the dive planner without turning it on.

Also, I'm just using Air, so what should my active gasses be set to?

Set it to Air (21/0).
The perdix can't plan multi level dives - for multi level dive planning you need to use software. Subsurface is good for this.

What the perdix can plan is a dive where you descend to a set depth and you stay at that depth for a set time.

You don't have to use the tech mode if you don't need to view the extra data without pressing buttons.