1000RR
Contributor
New here... recently certified... me and my daughter (13) did our first independent shore dive (Blue Heron Bridge) a week ago (tons of fun). I seem to spend a LOT of time reading a LOT of things here on Scubaboard and have also read Bob's article on dive planning as well. I wanted to find out if I'm thinking about our upcoming (1st for us) boat dive this coming weekend in the right frame of mind in regards to planning.
First, there will be a DM in the water, although this person will be there for the boat, not just us. We'll be diving out of West Palm Beach, FL: and will be doing what they consider their shallower reefs (45'-60'). It is a 2-tank dive and I am pretty sure the dive outfit pretty much made it 2 shallower reefs (as opposed to one deep, one shallow) because of my communications with them and having us as two new divers, one being a Jr. This dive op came recommended for that reason as well (they're good w/new divers and Juniors). Also, there is a good chance our instructor from our OW class may try and join us to to tag along (and provide support in however it might be needed). Very awesome of this fella to go out of his way to do this.
We are both comfortable in the water so that is not of concern... but being new divers, we don't know what we don't know (or have not yet experienced). So this first boat dive I plan to let my daughter know that our focus will be being good buddies (side by side, paying attention, etc.) and paying attention to our ascent rate as well as safety stop. Routinely checking pressure and working on buoyancy are givens we'll be working on. I also want to not rely on our instructor or DM to understand when to turn around and would like to have our own target so in case something happens, we have the context in which to fit our reactions in to. I've only got two data points for each of us for RMV rates. One was during training, one was on our own shore dive when we were exerting ourselves quite a bit early on. Daughter was 0.50-0.70, I was 0.72-0.89 with the higher numbers being when we were exerting a bit more.
I'm renting her AL80's w/Nx and me HP100's w/Nx since she seems to breath like a mouse (and I do not). We have all our own gear aside from tanks. So here are my thoughts. I am going to assume at this point, that it'll be a drift dive and the reef will be under the boat when we begin (ie. there's no navigating out and back). So for our turn around pressure, I was going to use 60' (figuring that should keep us on the conservative side) and figure that we'd use a combined RMV of 1.75 cf/min (I just added our higher RMVs and then added a tad extra on top of that).
- Assent from 60' to 15' = 1.75*(37.5/33+1)*1.5min = 5.61cf
- Safety Stop for 3 minutes = 1.75*(15/33+1)*3min = 7.64cf
- Assent from 15' to surf= 1.75*(7.5/33+1)*0.5min = 1.07cf
- Total = 14.32cf
- For the AL80, 14.32cf translates to ~555psi, add 500psi for minimum ending pressure, my daughter's turn around pressure is 1,055psi.
- For the HP100, 14.32cf translates to ~ 493psi, add 500 psi for minimum ending pressure, my turn around pressure is 993psi, call it 1,000psi.
Do you guys/gals agree with this? Should I have additional considerations? I would mentioned we have AI dive computers too... but those only assume they're going to get me back to the surface, not both of us since they calculate ATR based on my consumption rate (not our combined).
Thanks in advance... new to all this and want to begin our journey with good habits.
First, there will be a DM in the water, although this person will be there for the boat, not just us. We'll be diving out of West Palm Beach, FL: and will be doing what they consider their shallower reefs (45'-60'). It is a 2-tank dive and I am pretty sure the dive outfit pretty much made it 2 shallower reefs (as opposed to one deep, one shallow) because of my communications with them and having us as two new divers, one being a Jr. This dive op came recommended for that reason as well (they're good w/new divers and Juniors). Also, there is a good chance our instructor from our OW class may try and join us to to tag along (and provide support in however it might be needed). Very awesome of this fella to go out of his way to do this.
We are both comfortable in the water so that is not of concern... but being new divers, we don't know what we don't know (or have not yet experienced). So this first boat dive I plan to let my daughter know that our focus will be being good buddies (side by side, paying attention, etc.) and paying attention to our ascent rate as well as safety stop. Routinely checking pressure and working on buoyancy are givens we'll be working on. I also want to not rely on our instructor or DM to understand when to turn around and would like to have our own target so in case something happens, we have the context in which to fit our reactions in to. I've only got two data points for each of us for RMV rates. One was during training, one was on our own shore dive when we were exerting ourselves quite a bit early on. Daughter was 0.50-0.70, I was 0.72-0.89 with the higher numbers being when we were exerting a bit more.
I'm renting her AL80's w/Nx and me HP100's w/Nx since she seems to breath like a mouse (and I do not). We have all our own gear aside from tanks. So here are my thoughts. I am going to assume at this point, that it'll be a drift dive and the reef will be under the boat when we begin (ie. there's no navigating out and back). So for our turn around pressure, I was going to use 60' (figuring that should keep us on the conservative side) and figure that we'd use a combined RMV of 1.75 cf/min (I just added our higher RMVs and then added a tad extra on top of that).
- Assent from 60' to 15' = 1.75*(37.5/33+1)*1.5min = 5.61cf
- Safety Stop for 3 minutes = 1.75*(15/33+1)*3min = 7.64cf
- Assent from 15' to surf= 1.75*(7.5/33+1)*0.5min = 1.07cf
- Total = 14.32cf
- For the AL80, 14.32cf translates to ~555psi, add 500psi for minimum ending pressure, my daughter's turn around pressure is 1,055psi.
- For the HP100, 14.32cf translates to ~ 493psi, add 500 psi for minimum ending pressure, my turn around pressure is 993psi, call it 1,000psi.
Do you guys/gals agree with this? Should I have additional considerations? I would mentioned we have AI dive computers too... but those only assume they're going to get me back to the surface, not both of us since they calculate ATR based on my consumption rate (not our combined).
Thanks in advance... new to all this and want to begin our journey with good habits.
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