Ascent rate

[Prepare]

How do you tell your exact ascent rate?

I was just reading a post that said if your diving using deco tables and stray from the set ascent rate you will mess your profile up.

So how do you tell? I thought most computers show ascent rate as a % of max allowable?, not exact numbers like 4m/min etc.

I have only dived using 1 or 2 computers, and mostly stick to shallower dives using a bottom timer and depth guage.

Just interested to know.

 

[Uncle Pug]

Prepare once bubbled...
a bottom timer and depth guage.

Take 20 seconds to ascend 10 feet and you are ascending at 30fpm.

Do the same ascent in 10 seconds and you are ascending at 60fpm

Do the same ascent in 30 seconds and you are ascending at 20fpm

Do the same ascent in ...ect. ect. ect.

Get used to ascending in 10' steps and pay attention to your timing.

 

[Alban]

Hello Prepare

If you come up using a smb and reel you could put some marks on the line this may help with a visual reference .If you have come up to a mark a little fast wait there until the elapsed time before moving on and as Uncle Pug said pay attention to your timing Also what is helpful is a nice size reel as you wind the reel in you can judge your ascent speed by how fast your cranking the handle , keep the line reasonably taunt but obviously not to the point where you are winching yourself up.

Some computers and timers have a variable ascent speed so they will bring you up a little quicker from depth and slow you down in the shallower range.

Uwatec computers are shown here http://www.uwatec.com/english/m08-faq.htm

Yours Alban

 

[SSIdiver02]

I have recently read "The Last Dive" by ernie Chowdury :book2:. If his Computer is messed up or he is in trouble he uses the "stay below your bubbles technique", saying that yo shouldnevr ascendfaster than your bubbles do. By the way if anyone has not read the book...please do yourself a favor and read it...you will learn a lot! :grad:

 

[dmdalton]

Back in '62 when I started diving they taught the no faster than your smallest bubbles which worked out to about 60 fpm. If you stop each 10 ft for 20-30 seconds it slows your overall assent to roughly 30 fpm.

Dave D

 

[AquaTec]

In the early days you where taught to ascend no faster than your smallest bubbles. or if you can see you bubbles while ascending then you are going to fast. this method works out to about 60 feet per minute.

Today of course most computers will tell you if you are going to fast, and most are set at 60 feet per minute.

most dives require a slower ascent rate than 60 feet per minute

I use different ascent rates at different stages of a dive so I will use way points.

meaning I should be at a certain depth at a cetain time

some examples of ascent rates

400 to 200 at 75 ft/min with deep stops in between
200 to 100 at 30 feet/min with deco stops in between
100 to 20 at 15 feet/min again with deco stops in between
20 to zero at 2 foot/min on dives in the 300 foot range, as i go deeper i will slow this ascent down to 1 foot/min
my last deco stop is always at 20 feet

My descent rates are general 100 feet/min for divers over 100 feet. but thats a different topic

 

[SM Diver]

AquaTec once bubbled...

Today of course most computers will tell you if you are going to fast, and most are set at 60 feet per minute.

I'd be surprised if most were set at 60/min. Both of mine will give you a slow down alarm at a rate faster than 33.

By the way, there is a well written article in this month's Diver's Alert on ascent rates.

 

[Atticus]

For what it's worth - the Aeris 750GT signals an ascent rate alarm if you exceed 60fpm. There is a "yellow" range that you pass through before setting off the alarm.

 

[Big-t-2538]

Pay attention to your bottom timer, and your depth. If you are diving deep (consider 80 ft. deep...not everyone is a tekkie) and you want to to a 30ft/min ascent to 20 ft. it should take you 120 seconds to go from 80 to 20...watch yourself at intervals, say at 70 ft, you shold be a 20sec., at 60 ft you should be at 40 sec....get the picture?


For the record, my computer's alarm is set at 30ft/min...which goes off when I'm playing around in say 60 to 40 feet of water chasing fish or toypedos or something else.

 

[Scuba]

Prepare wrote:

I thought most computers show ascent rate as a % of max allowable?, not exact numbers like 4m/min etc.

My computer has an ascent meter which shows if ascent rate is below 20 fpm, between 20-30, 30-40, 40-50, 60 plus. Other computers measure smaller increments but not exact numbers.