Perfect ascents - your view

[Dr Deco]

That is interesting, Mrs Mares, concerning exercise , slow ascents, etc. I would like to see a copy of that British PADI book.

Mike P (Dr Deco)

 

[Mrs Mares]

That is interesting, Mrs Mares, concerning exercise , slow ascents, etc. I would like to see a copy of that British PADI book.

Mike P (Dr Deco)

I must apologise, my Instructor must have tokd me, although there are small references to these points, and in the recreational dive planner it states that 'No decompression table can guarantee that decompression sickness will never occur even though you dive within the limits.'

 

[Dr Deco]

Mrs Mares:

Thanks for the update. Clearly your instructor is well informed. :1book:

That is a very fortunate case, indeed.

Dr D.

 

[eponym]

Hello, Helen.

As you seem to be absorbing the information you've received so far, I'll add one more item which might help you when thinking about your safety stops.

The depth at which you take your safety stop (or any decompression stop, for that matter) is a balance, a trade-off, between competing forces. On one hand, you don't want to be too shallow, which can increase your chances of getting bent. On the other hand, the deeper you are, the longer you'll have to stop there in order to get the same off-gassing benefit.

When a dive site permits it, a slow meander in the shallows, moving from the bottom to the top of your safety stop depth range, can be much more interesting than finning in place and looking at your watch. Where in the UK are you diving?

Cheers,
Bryan

 

[Doc Intrepid]

Helen, just to climb onto the bandwagon, for recreational no-decompression limit diving I also advocate not exceeding 30 fpm during your ascent, and halting your ascent at 10'. Some recommend a minute at 20' and two minutes at 10', others 3 minutes at 15'. To some extent, if diving in open ocean the surface conditions may influence where you choose to do your safety stops. Just ensure you do them. The final point is that from 10' to the surface should be an extremely slow, controlled ascent. Its as important if not moreso than any other portion of the dive.

In terms of practical application, 30 feet per minute (sorry, I'm metric challenged) = ascending 10' every 20 seconds. Getting anal, thats about 1' every 2 seconds. The point isn't to get obsessive over it, but over time you'll identify this steady constant upward drift that roughly allows you to rise at a controlled rate of 10' every 20 seconds.

From a dive to 120', then, you would ascend for approximately two minutes to arrive at 60', where you would pause for a deep stop of perhaps two minutes (so four minutes total so far), then continue to take approximately another two minutes to ascend to 10', where you might pause for another three minutes (so nine minutes total so far). That last 10' of ascent, however, might take you up to another 40-60 seconds to drift up very slowly and surface. Possibly 10 minutes total - 5 actually ascending, 5 pausing for safety stops.

In terms of muscles and diving, etc., Cameron Martz (on this board) has a very useful site to review:
www.divefitness.com

Hope this helps,

Doc

 

[ihh]

Mrs Mares:

Thanks for the update. Clearly your instructor is well informed. :1book:

That is a very fortunate case, indeed.

Dr D.

Mike,

The PADI OW manual (english 2003) lists without much explanation vigorous exercise before, during or after the dive as one of a number of secondary factors that can contribute to DCS. More detail in later courses, Advanced, Deep Diving specialty and DM.

As to assent rate 60 FPM but slower is OK. The continuing Slowly Ascend From Every dive campaign pushes "slower than 60". As a recent IDC student, our Course Director and all of the students talked about 30 FPM, particularly from 15 feet up.

Hugh

 

[baitedstorm]

Helen,
Just wanted to chime in on these great responses and remind you, if your boat diving, make sure your aware of the current before you start doing 10 min safety stops at 15-20ft and such. You'll end up pretty far of course, best to speak to the captain before planning your dive. We (hubby and I) will usually do several safety stops (1 minute each) if we are deep (below 60 feet) and limit the 15-20ft safety stop to 3 minutes. If the current is mild, you should have no worries at all doing however many safety stops you want.
Good luck, keep us updated.
Vickie