Ascent from a beach dive at 20-30 ft

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ctx120

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A discussion about the way I ascent from depths of 20-30 ft make me wonder which way is correct
I have heard two different scenario about how to ascent from a beach dive.
At a depth of 20 -30 ft I watch my computer gauge while I ascent if I trig alarm I slow up .
The reason I was once told the shallower the more a chance of dcs (air expands much faster the closer we get to the surface)
The reason I asking I never heard of this before.
On a beach dive in 20-30 ft I was told I take too long, and the proper way to ascent is to release all the air in my lungs
and I would float to the surface much faster. It doesn’t matter I still going to take my time from a 20-30 ft beach dive , they can wait 1 extra minute for me .
 

Easdem

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Who told you advice #2? Tell them they need retraining. ASAP.

A slow neutrally buoyant ascent is the way to do it, try to stay slower than 30 feet per minute.

I like to slow down even more for the last 10 feet.



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ctx120

ctx120

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That exactly what I thought , she told me that as a scuba diver and free diver that the way she was taught .I taughted my son and grandson to ascent all low level dives to ascent at a slow rate no matter what other might think .Let them wait on the surface .
Thanks
 

TSandM

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I don't quite understand the original post -- was someone telling you to exhale and just let your expanding BC air take you to the surface? If so, that is VERY bad advice. It isn't just air expanding in your lungs that you have to worry about when diving; it's also the nitrogen in your blood, forming bubbles and then expanding.

You came away from your class with precisely the right understanding: The proportional pressure changes are greatest in the shallow water, and that is where you want your ascent rate to be the slowest. When we are coming up from deeper dives, we play with taking six full minutes to get from 20 feet to the surface. Not only is that good for your decompression status, it's also great practice in buoyancy control!
 

Icker96

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I think there was some confusion. The ascent she described would be from her free diving training where there is no concern for air expansion or nitrogen. When scuba diving, slower is ALWAYS better (at least almost always&#128516:wink:
 
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ctx120

ctx120

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I think there was some confusion. The ascent she described would be from her free diving training where there is no concern for air expansion or nitrogen. When scuba diving, slower is ALWAYS better (at least almost always&#62980:wink:

What everybody said is how I feel .the last post about her free diving is true and she uses it while she scuba dives , and she was trying to tell me I need to do the same .I just said sure -but under my breath I really said hope u don't end up in the hospital .

Just wanted to make sure I was on the right track , I see so many beach divers just ascenting to the surface because they forgot about a slow ascent in shallow dives .I am always the last one up , if my computer beeps I stop for a second & then proceed again .

Thanks for all information posted
 

whodunit68

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it doesn't matter if you're doing an ascent from a beach dive or you will ascend from a quarry dive or a shallow boat dive on a reef. The greatest percentage change in pressure occurs as you get closest to the surface. Very simple math will show you this.
Air Pressure at surface: 1 ATA
Pressure at 33': 2 ATA
Percent of change: (2 ATA - 1 ATA)/1 ATA = 100%

Pressure at 33': 2 ATA
Pressure at 66' (33' + 33'): 3 ATA
Percent of change: (3 ATA - 2 ATA)/2 ATA = 50%

Pressure at 66': 3 ATA
Pressure at 99' (33' + 33' + 33'): 4 ATA
Percent of change: (4 ATA - 3 ATA)/3 ATA = 33.333%.

You can see the percentage is decreasing. It means as you ascend, the reverse is true. Air will expand much faster as you get closer to the surface. Listen to what you learned in class and your gut was telling you, go SLOOOOOW. As suggested above, 30fpm ascent is the fastest recommended at that depth.
 
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Insta-Gator

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DAN | Medical Frequently Asked Questions


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BTW: on a personal note, I will take between 3 to 5 minutes ascending from 15 feet. That is 'watching paint dry' slow, but I occupy myself by looking around, checking on others, making sure I have my act together before ascending. There's no hurry. If nothing else, think about making your ears and sinuses happy.
 

HalcyonDaze

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I don't ascend quite that slow from 15 feet, but I generally dump all the air out of my BC and slowly creep upward on fin power. Overall though, slow is good there.

One beach dive experience that rankled me to no end was on a checkout dive for an aquarium's volunteer dive team. Things went badly before we even got wet; at the initial meeting when handing around our certs and logs I was critiqued for having a "low level of certification" (AOW and nitrox, plus having been an American Academy of Underwater Sciences diver with two different universities for a combined period of six years) and a "low level of activity" (14 dives in the previous 12 months, with 330 career dives over a 9-year period). The guy next to me, whom I ended up buddied with, had only done his OW course 9 months earlier ... but he had 100 dives logged and was going for instructor! Not a peep from the assistant DSO about his experience level.

On the checkout dive, we were "graded" according to the PADI manual, which was another alarm bell - I care less about how pretty my technique looks than whether or not it gets the job done, and the manual doesn't cover everything. When it came time for the shared-air ascent (me as donor for the first run) from 25 feet, my buddy does the bog-standard "clasp arms, remain face to face, hang onto buddy's BC." Well, with my wrist computer pinned against my torso and me breathing off an Air2 with no remote dump, I would prefer having both arms free. So I did what I felt was the sensible thing - ditched every last bit of air from my BC and ascended on my fins, going pretty darn slow because I couldn't see the thingamajigger telling me how deep I was or how fast I was going. Got chewed out and told I needed "remedial training" for taking so long to ascend with an out-of-air buddy. Needless to say, I decided I didn't need to go through that level of crap to dive in a fish tank.

Since then I make a point before diving with a new buddy of showing them that I have a 5' cave diving hose on my primary. I tell them that in the event of them needing air, I will give them that reg, and they will be fine. There is no need to clamber up on me like a starfish or a possessive girlfriend, and there is no need to bolt for the surface. In the three years since then, I've had to do three shared-air ascents, one of which was a buddy's reg freezing at 100 feet.
 
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