Should I get HP-117 or HP-120 tanks?

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12-06-2021 08:52 PM
twaldo

Quote:

Originally Posted by tbone1004

buddy of mine has a saying "when you look like a manatee, you can dive like a manatee" particularly with regards to diving in cold water in shorts. If you're only doing hour long dives and you have a lot of bioprene I can get it.

THANK YOU... because while I lived in cave country that was COMPLETELY it... I was 300+ lbs and was doing (yeah right I know woohoo) 60 to 70 minutes of dive time and toasty when I exited the water. I've been slowly moving to drysuit since having lost the weight..
12-06-2021 09:06 PM
twaldo

Quote:

Originally Posted by tbone1004

one could argue so you aren't breaking the law when cave filling them...

practically speaking the buoyancy characteristics can be better for some divers and if you are wearing lead anyway then it may as well be in the tanks.

ok, I'm guilty of doing cave fills but I also like my LP85's for open water dives at their stated fill pressure... This is the part I don't understand.

a HP 120 gets you 120cuft of gas at 3400psi but an LP120 at 3400 gets you 170cuft of gas?? I was guessing at the actual fill pressure of an HP cylinder, did I do my math wrong? Why go HP if the cylinders have the same characteristics?? A lot of places won't fill over 3200 psi no matter what cylinder you have so again LP would win out...
12-06-2021 09:23 PM
tbone1004

Quote:

Originally Posted by twaldo

ok, I'm guilty of doing cave fills but I also like my LP85's for open water dives at their stated fill pressure... This is the part I don't understand.

a HP 120 gets you 120cuft of gas at 3400psi but an LP120 at 3400 gets you 170cuft of gas?? I was guessing at the actual fill pressure of an HP cylinder, did I do my math wrong? Why go HP if the cylinders have the same characteristics?? A lot of places won't fill over 3200 psi no matter what cylinder you have so again LP would win out...

remember Z-factor and compare apples to apples
LP95=FX117 *or same capacity as HP120, just long and skinny vs short and fat*
LP120=HP149
LP85=HP100

same internal water volume means same capacity at the same pressure. LP85 and FX100 have the same water volume so whenever they are filled to one pressure they have the same capacity. The FX100 is 3lbs heavier, but if you can get full fills from a recreational ship then you get the gas, and it's also 3lbs more negative in the water so if you are wearing lead then it washes out.
https://kaplanindustries.com/wp-cont...tions-2019.pdf
12-06-2021 09:37 PM
rddvet

Should I get HP-117 or HP-120 tanks?

Quote:

Originally Posted by tbone1004

buddy of mine has a saying "when you look like a manatee, you can dive like a manatee" particularly with regards to diving in cold water in shorts. If you're only doing hour long dives and you have a lot of bioprene I can get it.

But what twaldo is saying is he?s warmer in ahorts which is complete bullsh-t. But yeah if youre fat enough you can not feel cold swimming in the caves. The laws of physics make it physically impossible for him to be warmer with shorts on bs a protective garment made to retain heat.

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12-06-2021 09:39 PM
twaldo

Quote:

Originally Posted by SUB ZERO

I could have asked this question on so many forums but I wanted to ask cave divers since you all are "masters of trim." I would like to buy a few tanks for single tank diving in wet and drysuit. I am 5.10 and wide built. Would an hp-120 tank be too long on me to make me bottom heavy and upset my trim? I was thinking of getting the HP-117 as it is shorter and fatter and holds almost the same gas but to those who use HP-120, how short can you be to still make that tank work without upsetting your center of gravity and tilting you head up?

Thanks.

Sorry for hijacking your thread, just curious though, still considering HP cylinders?
12-06-2021 09:44 PM
twaldo

Quote:

Originally Posted by rddvet

But what twaldo is saying is he?s warmer in ahorts which is complete bullsh-t. But yeah if youre fat enough you can not feel cold swimming in the caves. The laws of physics make it physically impossible for him to be warmer with shorts on bs a protective garment made to retain heat.

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Ok, you are biased in your statement. Body physiology does allow for it. I first read about this in a SCUBA specific book and it explained it in much greater detail than this article from a runners magazine.... HOWEVER the article covers most of it... it isn't just breath hold free divers. SO MAYBE you guys will STOP with the drysuit shaming...
https://www.runnersworld.com/trainin...-pearl-divers/
12-07-2021 04:35 AM
Diverlee

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12-07-2021 06:20 AM
rddvet

Should I get HP-117 or HP-120 tanks?

Quote:

Originally Posted by twaldo

Ok, you are biased in your statement. Body physiology does allow for it. I first read about this in a SCUBA specific book and it explained it in much greater detail than this article from a runners magazine.... HOWEVER the article covers most of it... it isn't just breath hold free divers. SO MAYBE you guys will STOP with the drysuit shaming...
https://www.runnersworld.com/trainin...-pearl-divers/

I wont say anymore after this. I really dont give a crap if you wear a drysuit or not. You just like to say really stupid stuff and its annoying.
That article you posted in no way is a scientific basis for what you think you feel.
I?ll just try to ignore your idiocies.

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12-07-2021 08:10 AM
twaldo

Quote:

Originally Posted by rddvet

I wont say anymore after this. I really dont give a crap if you wear a drysuit or not. You just like to say really stupid stuff and its annoying.
That article you posted in no way is a scientific basis for what you think you feel.
I?ll just try to ignore your idiocies.

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The article just touched on what the diving book elaborated on considerably, wish I could cite the book, it was on technical diving. Though I TOTALLY agree , you should just ignore any post I create... I'm tired of arguing what my comfort level is or was in 72 degree water.
12-07-2021 08:15 AM
rddvet

Quote:

Originally Posted by twaldo

I'm tired of arguing what my comfort level is or was in 72 degree water.

Then stop bringing it up or referring to your feud with Draker.
And again, I dont doubt your comfort. I can wear shorts when its 25 degrees outside. But your claims of being warmer that way are just stupid

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