Deepest Dive First, no exceptions?

[tbone1004]

Based on five whole dives with the oldest (our current big breather) I figure we'll get 40 mins max on our AL80s. And as you said, that wouldn't be a square profile either. He doesn't seem to be nervous breathing, he just burns through it by: sprinting, turning to check on his buddies (me and the youngest, so far) and then repeat.

I appreciate your write up. I am reading all of the posts. Not because I need it this weekend (I now know) but because I do like understanding what I am getting into as our skills/comfort/depths increase.

also of note is that when you dive Nitrox, even if planning on doing identical dive profiles, it is important to calculate your EAD for each bottle and dive the "deeper" mix first to maximize your bottom time. I.e. if doing identical dive plans with one dive on air, one on EAN32, you'll want to dive the air tank first since it's "Deeper".

 

[tursiops]

also of note is that when you dive Nitrox, even if planning on doing identical dive profiles, it is important to calculate your EAD for each bottle and dive the "deeper" mix first to maximize your bottom time. I.e. if doing identical dive plans with one dive on air, one on EAN32, you'll want to dive the air tank first since it's "Deeper".

?? Maybe this is backwards?
80 ft on air is 30 mins max (PADI RDP), group R, 45 mins >> SI group I, 2nd dive to 80 ft on 32% allows 22 mins, thus 52 mins total BT at 80 ft.

But 80 ft on 32% is 45 mins max, group T, 45 mins SI >> group J, 2nd dive to 80 ft on air allows 11 mins, thus 56 mins total BT at 80 ft.

 

[tbone1004]

?? Maybe this is backwards?
80 ft on air is 30 mins max (PADI RDP), group R, 45 mins >> SI group I, 2nd dive to 80 ft on 32% allows 22 mins, thus 52 mins total BT at 80 ft.

But 80 ft on 32% is 45 mins max, group T, 45 mins SI >> group J, 2nd dive to 80 ft on air allows 11 mins, thus 56 mins total BT at 80 ft.

PADI RDP is very different than the NAUI tables that I'm used to. They are optimized for very different things. PADI for repetitive diving, NAUI for one long dive. When doing exercises like this it is important to choose the tables that best suit the diving you are doing instead of subscribing to one flat out. Adapt. It is also important to try to dive with similar tables, otherwise you're going to get all sorts of annoying things going on.
EAD is 65ft

For NAUI you get 35 mins on air at 80ft, then after 45 mins you get 8 minutes on EAN32. Do it backwards and you get 45 mins on the first dive and can't make a second dive. Being based on the USN tables the NAUI tables are optimized for one long dive per day, so SIT's kill you. If you made that SIT 1:10 instead of 0:45 then you 35:14 and 45:8.

 

[boulderjohn]

PADI RDP is very different than the NAUI tables that I'm used to. They are optimized for very different things. PADI for repetitive diving, NAUI for one long dive. When doing exercises like this it is important to choose the tables that best suit the diving you are doing instead of subscribing to one flat out. Adapt. It is also important to try to dive with similar tables, otherwise you're going to get all sorts of annoying things going on.
EAD is 65ft

For NAUI you get 35 mins on air at 80ft, then after 45 mins you get 8 minutes on EAN32. Do it backwards and you get 45 mins on the first dive and can't make a second dive. Being based on the USN tables the NAUI tables are optimized for one long dive per day, so SIT's kill you. If you made that SIT 1:10 instead of 0:45 then you 35:14 and 45:8.

This is exactly what I referred to in a previous post. Back in 1972, the first time the suggestion for doing the deepest dive first appeared, everyone was diving the US Navy (and current NAUI) tables. As indicated above, they had extremely long surface intervals, which did not concern the Navy because they usually only did one long dive a day anyway. That is not, however, how recreational divers dive. They like to do 2 or more shorter dives a day, and those long surface intervals were really screwing up dive schedules. The practice of doing the deepest dive first made a huge difference, but the surface intervals were still very, very long. Doing the deepest dive second really put many of those second dives out of reach on a given dive day.

That is why PADI did the research that led to its RDP. It wanted to see if those surface intervals were necessary for the kind of dives being done by recreational divers. The research showed that those long surface intervals were not at all necessary--they could be based on theoretical tissues that saturated in 1/3 the time of the theoretical tissues used by the Navy. They chose to be more conservative than that, though. This led to more manageable dive schedules for recreational divers, and it really should have put to rest the deepest dive first "rule."

 

[drbill]

I've done reverse profiles many, many times but almost always stayed within the parameters indicated on my dual computers. Occasionally I'd end up in deco, but I don't consider that a problem since I always extend my deco time 2-4X what my computer recommends.

Since your dives will be shallow, I don't think you should worry too much in the event you do a reverse profile.

 

[tursiops]

PADI RDP is very different than the NAUI tables that I'm used to. They are optimized for very different things. PADI for repetitive diving, NAUI for one long dive. When doing exercises like this it is important to choose the tables that best suit the diving you are doing instead of subscribing to one flat out. Adapt. It is also important to try to dive with similar tables, otherwise you're going to get all sorts of annoying things going on.
EAD is 65ft

For NAUI you get 35 mins on air at 80ft, then after 45 mins you get 8 minutes on EAN32. Do it backwards and you get 45 mins on the first dive and can't make a second dive. Being based on the USN tables the NAUI tables are optimized for one long dive per day, so SIT's kill you. If you made that SIT 1:10 instead of 0:45 then you 35:14 and 45:8.

So why are you talking about repetitive dives with the NAUI tables? Seems like you are "subscribing to the NAUI tables flat out."

 

[tbone1004]

So why are you talking about repetitive dives with the NAUI tables? Seems like you are "subscribing to the NAUI tables flat out."

I teach for NAUI, don't have much of a choice. I am thoroughly opposed to their use of RGBM and the old tables, but such is life. Can't change a dinosaur

 

[tursiops]

I teach for NAUI, don't have much of a choice. I am thoroughly opposed to their use of RGBM and the old tables, but such is life. Can't change a dinosaur

I teach for PADI and SDI/TDI, but I don't feel obliged to use their tables unless it is a class.

 

[tbone1004]

I teach for PADI and SDI/TDI, but I don't feel obliged to use their tables unless it is a class.

i don't use anyones tables, ever... I use the rule of 130 if for whatever reason I have lose computers, but use gradient factors for all of my diving. For recreational diving I will "ride" the computer, and since my technical diving is usually one big ass dive per day, the plans are easy enough to not worry about

 

[BoltSnap]

i don't use anyones tables, ever... I use the rule of 130 if for whatever reason I have lose computers, but use gradient factors for all of my diving. For recreational diving I will "ride" the computer, and since my technical diving is usually one big ass dive per day, the plans are easy enough to not worry about

What do you use in your teaching NAUI courses?