The last few feet

[rjpv]

Hi folks,

I'm a new diver with a question. I was (recently!) taught to ascend no faster than 60fpm, though after talking with some DMs I have decided 30fpm is the better rate - which is fine, I like to ascend at a slow swim that seems about right.

My question is, perhaps due to BCD air expansion, the last 5 feet or so tends to by pretty much in the blink of an eye. I'll be slowly finning upward, taking my time, when I hit a few feet from the surface and all of a sudden I'm there. (I should also note wearing a full 7mm wetsuit)

How much of a problem is this in terms of DCS risk? Is there a way around it?

Oh and yes, as a new diver these are all NDL dives no deeper than 60 feet with me staying at least 3 boxes away from the evil zone of decompression on my table.

 

[scubadobadoo]

Not much of a risk assuming you went slowly before but that doesn't mean that you should still do it. With only 0-15 dives, the last 5 feet are the hardest, but you will get better with every dive you do. Your skills will likely improve drastically with every dive you do within the first 50 or so. You will also continue to dial in the amount of weight you really need as you dive more. I remember someone once told me to make a game out of the last 20 feet. See how slowly you can do it and really concentrate on doing it so slowly that it seems silly. I did this and instantly noticed improvement in my control and how I felt after dives. Of course, this isn't always possible on every dive depending on conditions but I try to do it when I can. Have fun and welcome to diving!

 

[H2Andy]

well... the last five feet *probably* won't be much of a problem

but it tells me

a. you are not neutral or slightly negative with a near-empty tank near the surface; or

b. you are not squeezing all the air out of your BC as you ascend


try to make sure you are not doing (b) first. make sure you keep dumping that
air as you ascend. you should be able to have full control of those five feet
(i can just sit there for as long as i want, and slowly come up to the surface,
and my bouyancy isn't really that good).

if you find that you are dumping all the air and still can't control your final ascent,
then you may be a little light on weight. adding 1 or 2 lbs should take care of this.

i would recommend not adding the weight right away. you probalby don't need it.
your problem is probably not letting all the air out of the BC.

 

[Charlie99]

My question is, perhaps due to BCD air expansion, the last 5 feet or so tends to by pretty much in the blink of an eye. I'll be slowly finning upward, taking my time, when I hit a few feet from the surface and all of a sudden I'm there. (I should also note wearing a full 7mm wetsuit)

It's quite likely just the effect of the 7mm suit expanding as you rise, coupled with being weighted right on the edge.

You could add a few pounds of lead, but before doing that, try keeping your lungs closer to empty for just those last few feet. Since you will just spend 10 or 20 seconds in this real shallow area, it's OK to have a bit of an awkward breathing pattern for that short time. The tradeoff is 3 or 4 pounds less lead.

Also, rather than finning upward, try floating horizontally -- this gives a lot more up/down drag and makes control a bit easier.

 

[rjpv]

Hmm, ok. Before I load up on weight I'll try better controlling my breathing and the horizontal "drift". Thanks!

 

[DandyDon]

I try to stay slightly negative on ascent, having to fin a little to ascend without a mooring line - especially the last few feet. Another reason I like to be slightly negative at the end of a dive.

Once on the surface and sure there's not a jetski coming, I full inflate and take another 1-2 min stop before swimming.

 

[Kangy]

Hmm, ok. Before I load up on weight I'll try better controlling my breathing and the horizontal "drift". Thanks!

A) yes 30fpm is the recommended ascent rate which is for the most part accepted, there are still a few teaching 60 though but I do believe that is in the works for being revamped soon.

B) you said "due to bc air expansion" are you doing as H2Andy said, make sure you are dumping the air as needed as you ascend

C) choosing not to load up on weight is probably the smarter way, there are too many beginning divers that are terribly over weighted due to not being taught that in class. however being underweighted can also cause issues, so it's kind of the thing where you have to find your median.

Right now you should be weighted correctly so as to hold a 10ft stop with 500psi left in your tank, no air in your BC without sinking or raising to the surface? if you can't hold that stop at the end of your dive adjust your weight from there.

The horizontal ascent is great it will take some practice but will give you alot more control over your ascent