What size doubles?

[Mr. Bubble]

Great info everyone...thanks

I''ll see what the crew says and keep this info to decide.

Thanks again

Mr.B

ps. just from my enternet research

HP100 = 7x24 33lbs
lp 85 = 7x25 35lbs
lp 95 = 8x23 41lbs
HP 100's are one inch shorter, a double set would be 4 lbs lighter and have 30 cf more gas ( a whole pony bottle). Something to concider. WIth good fills of coarse.

 

[Rainer]

Great info everyone...thanks
HP100 = 7x24 33lbs
lp 85 = 7x25 35lbs
lp 95 = 8x23 41lbs
HP 100's are one inch shorter, a double set would be 4 lbs lighter and have 30 cf more gas ( a whole pony bottle). Something to concider. WIth good fills of coarse.

A few things to consider.

This assumes 3442 fills on the HP100s and only 2640 on the LP85s (service pressure is NOT 2400). If you can't get 3400 in the HP cylinders, *and* can get around 3000 in the LP85s, the "85s" will be holding more gas than the "100s". If you do get fills only to service pressure (i.e. can't get any overfill in the LPs), then the HP100s will still be only about TWO pounds lighter, since you'll be hauling around extra gas in the bigger cylinders. The HP100s are also going to set you back an extra $200-300.

 

[xiSkiGuy]

Just clear a few things up: LP tanks are rated to 2400psi plus 10% (or 2640psi). When the volume of a LP tank is given (LP85, LP95, LP104, etc) it includes the 10%. So, LP tanks are at their rated volume when they are at 2640psi. A single LP95 that is only filled to 2400psi has a little over 86cf of gas in it.

On any tank to determine volume at any given pressure (to find out how much gas in cubic feet X tank has at Y psi): Divide the rated volume by the rated pressure and then multiply by the actual pressure (or desired pressure or whatever).

For example, a LP85 holds 85cf of gas when filled to 2640psi.
85cf divided by 2640psi = 0.0322cf/psi
0.0322cf/psi multiplied by 3600psi = 115.92cf
So a LP85 that has been filled to 3600psi has almost 116cf in it.

For example, an X8-130 holds 130cf of gas when filled to 3442psi.
130cf divided by 3442psi = 0.0378cf/psi
0.0378cf/psi multiplied by 3000psi = 113.4cf
So a X8-130 that has only been filled to 3000psi has 113.4cf in it.

 

[xiSkiGuy]

Thanks everyone....WHy do some of youadvocate the LP rather than the HP ?? I can't imagine an LP having more CF of air than a HP filled to 3442.

A HP100 filled to 3442 has 100cf in it. A LP108 filled to 2640 has 108cf in it.

Yes, both the NC coast (U352 fyi) and the North Florida springs are about the same distance. I went on a NC dive this past summer and the DM had HP95's.

If the DM was Kenny on Diverdown, they were LP95s (and I was on the trip).

 

[Mr. Bubble]

So, yeah...Hp100's at 3000psi is only 87cf and the lp85's would be 96cf. with doubles that would be 38cf less with the twin Hp100's.

Gives the argument to get good fills does'nt it? How much of a problem is it getting 3442 fills? I have not had that much trouble thus fare. Is this a rampant problem, or something you only run ito occasionally? I definately have to get them topped off, but have never had anyone say they could'nt do it, although I have heard people mention it. Then you also have to be with a shop that will over fill 5-600 lbs over rating for the lp tanks.

 

[xiSkiGuy]

Gives the argument to get good fills does'nt it? How much of a problem is it getting 3442 fills? I have not had that much trouble thus fare. Is this a rampant problem, or something you only run ito occasionally? I definately have to get them topped off, but have never had anyone say they could'nt do it, although I have heard people mention it. Then you also have to be with a shop that will over fill 5-600 lbs over rating for the lp tanks.

It depends on where you dive. You mentioned cave diving. Shops in cave country pretty much fill all steel doubles to 3600psi (or more), regardless of rated pressure. Some shops in other places will fill to rated pressure only. The occasional shop will put whatever you want in the tank once you've developed a good relationship with them. Getting fills off of a boat compressor will probably limit you to 3000psi (or less).

IMO if LP85s had an exemption equivalent, they would be just about the perfect all around doubles.

 

[Eris Lucan7*]

You need 2 off the 12liter High Polaris tanks,you can not have that......

E.L.7*

 

[Mr. Bubble]

What size wing would be best? 45,60, 85,90? Remember, I may have some stage bottles as well.

Thanks

 

[Rainer]

What size wing would be best? 45,60, 85,90? Remember, I may have some stage bottles as well.

Thanks

Add up those bits of kit that are negative and those that are positive. Your wing needs to float your rig (with you out of it) and you in the rig with maximum compression/drysuit flood. People on the internet can only guess about your rig. Do the math yourself. Stage bottles don't factor into the calcs for wing selection.

 

[xiSkiGuy]

What size wing would be best? 45,60, 85,90? Remember, I may have some stage bottles as well.

Thanks

We would need to know which tanks you would be using and what exposure protection. But you can definitely rule out anything with more than 70lbs of lift.

Most people recommend aluminum stages/deco bottles and they don't change your wing needs very much.