Kray_Z
Guest
Meng_Tze:I thought BT was the time you spent lying on the bottom?
no its the time spent sitting around on the boat waiting to dive... duh
what is bottom time?
- Thread starter bob1dp
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no its the time spent sitting around on the boat waiting to dive... duh
Mauifish
Contributor
Bottom time is what I had with my girlfriend last night, I tell ya what, bottom time IS my favorite time!!!
Kray_Z
Guest
Mauifish:
shes my favorite bottom time too!
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U.S. Navy (old school) says 30:10.
Mauifish
Contributor
Hey!! you plan your own dive!!!:no I am a territorial fish!Kray_Z:shes my favorite bottom time too!
Kray_Z
Guest
Mauifish:
oh come on... ill just be the third wheel in the dive buddy situation... cant wait for some ooa drills
A square profile assumes a direct ascent
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"Crawfishdiver's answer was correct under the definition of bottom time SSI uses and he said he was using SSI tables. Bottom time is the time from the beginning of the descent to the beginning of the direct ascent to the surface. to the surface only begins after the safety stop. Other agencies may define it differently. "
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A 60 ft/min or a 30 ft/min ascent is a direct ascent and is not included in bottom times regardless of what an agency states.
Many divers who have done mutlilevel diving for many years WITHOUT a computer develop (secret) methods. Several of us have such methods and they are not discussed as to the exact method. Why are they secret?
1) they evolve and change as more is leanred
2) we (me) would wish to take no responsibility in getting somebody hurt using our (my) method as there is simply no way to transfer the knowledge completely via the internet in a chat forum.
N
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"Crawfishdiver's answer was correct under the definition of bottom time SSI uses and he said he was using SSI tables. Bottom time is the time from the beginning of the descent to the beginning of the direct ascent to the surface. to the surface only begins after the safety stop. Other agencies may define it differently. "
----------------------------------------------------------------------------------
A 60 ft/min or a 30 ft/min ascent is a direct ascent and is not included in bottom times regardless of what an agency states.
Many divers who have done mutlilevel diving for many years WITHOUT a computer develop (secret) methods. Several of us have such methods and they are not discussed as to the exact method. Why are they secret?
1) they evolve and change as more is leanred
2) we (me) would wish to take no responsibility in getting somebody hurt using our (my) method as there is simply no way to transfer the knowledge completely via the internet in a chat forum.
N
OP
bob1dp
Contributor
So when I look at my PADI Dive planner it says the no deco limit for 110 is 16 minutes of BT. So does that mean if I start my stop watch when I start my dive to 110 and when I hit 16mins at 110 I start up my bottom time is 16 minutes? Therefore the dive is within nodeco limits and I only need to stop at 15 for 3 minutes.
bob1dp, I am not going to specifically answer your question because it uses a PadI dive table which I have never seen and apparently does not agree with the original Navy Tables I use as my baseline table regardless of what additional safety stops, reduced ascent rates, deep stops etc and etc I might add.
Bottom time in every book I have read on it for a square profile dive as you just described is from beginning of ascent until your beginning of a standard rate ascent to surface or first stop.
The Navy Tables show 20 minutes at 110 feet (which includes the descent time) with 60 ft/min ascent direct to the surface, no safety stop is implied or requested. While safety stops are SOP these days they have not always been. In any case, a safety stop and a slower ascent rate of 30 ft/min does not alter the basic table requirements.
Here is a better way of looking at all of this from a physical standpoint. Bottom time is the on gasing portion of the dive and standard rate direct ascents/safety stops/ deco stops are assumed to be off gasing and therefore are not included in bottom time. Therefore when you stop on gasing nitrogen your bottom time effectively ends. Now, imagine, if over many years you had worked out a strategy that acounted for off gasing and on gasing (tissue loading) in a multi level profile. That is really what your interested in, when your taking on nitrogen and when your giving it up so that you end up with either no deco required or at least a minimum amount. Maybe I don't explain that well. N
Bottom time in every book I have read on it for a square profile dive as you just described is from beginning of ascent until your beginning of a standard rate ascent to surface or first stop.
The Navy Tables show 20 minutes at 110 feet (which includes the descent time) with 60 ft/min ascent direct to the surface, no safety stop is implied or requested. While safety stops are SOP these days they have not always been. In any case, a safety stop and a slower ascent rate of 30 ft/min does not alter the basic table requirements.
Here is a better way of looking at all of this from a physical standpoint. Bottom time is the on gasing portion of the dive and standard rate direct ascents/safety stops/ deco stops are assumed to be off gasing and therefore are not included in bottom time. Therefore when you stop on gasing nitrogen your bottom time effectively ends. Now, imagine, if over many years you had worked out a strategy that acounted for off gasing and on gasing (tissue loading) in a multi level profile. That is really what your interested in, when your taking on nitrogen and when your giving it up so that you end up with either no deco required or at least a minimum amount. Maybe I don't explain that well. N
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