Blackwood
Contributor
Would I dive what profile?
Three depths alone aren't enough for me to conclude whether I'd do it.
Three depths alone aren't enough for me to conclude whether I'd do it.
Would you dive this profile?
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Supershark
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I regularly do 3 dive days with the following profile:
Dive 1 Wreck BOTTOM 35 metres, top 18 metres, if dived properly 45 min dive.
Dive 2 Pinnacle BOTTOM 25 metres, top 5 metres, if dived properly 60 min dive.
Dive 3 Wall BOTTOM 20 metres, end dive 5 metres, if dived properly 60 min dive.
1 hour 15min SI between each dive.
I stress the word bottom here to show that you do not always have to do the max depth. I get new buddys everyday. I have found that in any buddy team both members need to be pro-active. If your buddy is very quiet is he showing signs on pre-dive stress. Talk and learn about your buddy. Remember you and your buddy are there to help each other and to share a dive experience, by getting to know them improves safety and increases the fun. I don't know about everybody else but I got into diving for enjoyment, not stress!
Dive safe
Dive 1 Wreck BOTTOM 35 metres, top 18 metres, if dived properly 45 min dive.
Dive 2 Pinnacle BOTTOM 25 metres, top 5 metres, if dived properly 60 min dive.
Dive 3 Wall BOTTOM 20 metres, end dive 5 metres, if dived properly 60 min dive.
1 hour 15min SI between each dive.
I stress the word bottom here to show that you do not always have to do the max depth. I get new buddys everyday. I have found that in any buddy team both members need to be pro-active. If your buddy is very quiet is he showing signs on pre-dive stress. Talk and learn about your buddy. Remember you and your buddy are there to help each other and to share a dive experience, by getting to know them improves safety and increases the fun. I don't know about everybody else but I got into diving for enjoyment, not stress!
Dive safe
You are obviously not comfortable with this dive arrangement. You are also missing some key details for this dive. Deep diving is nothing to be taken lightly and there should be a reason for the dive to begin with. In other words is it a wreck dive, a creature dive, ect. ect. I personally would find a more experienced buddy for this type of dive. It can be done but with extreme caution.
As the saying goes, "If it feels wrong, it is".
As the saying goes, "If it feels wrong, it is".
Randy43068
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Take the lead. The depths aren't a problem as I see it, so you tell him how long you're going to stay at the perticular depth, and also tell him what SI you ARE going to do.
If you've used a computer forever and don't recall the tables, we'll help out.
Also, you control the nice slow ascent and stops. If he doesn't agree, and this is what you are asking, no I wouldn't dive with him, which is the root of the question.
If you've used a computer forever and don't recall the tables, we'll help out.
Also, you control the nice slow ascent and stops. If he doesn't agree, and this is what you are asking, no I wouldn't dive with him, which is the root of the question.
ArcticDiver
Contributor
Like everyone else has said: This is a no dive situation. Two reasons: First, you haven't talked it over enough, or had enough experience with each other. Second, your main concern appears to be the other person's age. That tells me there is an attitude problem on your part and maybe the other person's also that puts a big Red X on you two being dive buddies on any dive.
nereas
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These depths are definitely nitrox depths, so if you have access, then you surely should use it for 3 repetitive dives like this.
If all you have is air, then I would highly recommend long surface intervals together with your NAUI, SSI, or PADI air tables, which are shortened over USN tables.
Otherwise, no big deal, as long as you do it right the first time.
If all you have is air, then I would highly recommend long surface intervals together with your NAUI, SSI, or PADI air tables, which are shortened over USN tables.
Otherwise, no big deal, as long as you do it right the first time.
I'm going to take a slightly different tack in answering your question...
Regardless of whether the profile is *technically* do-able or not... if YOU can't answer your own question, you shouldn't dive the profile. If you *older* buddy feels comfortable with it and understands it... that's his call... not yours... you make the call for you.
As others on this list have pointed out... there are a lot of other 'depends upon' elements to making the call... how you feel on a specific day, current, activity to be undertaken, how your buddy feels, temperature, whether or not you *feel like it* on the day of the dive, etc., etc... so while I can comment on whether or not the profile is *technically feasable* or not... yea... of course it is... as to whether or not *I* would dive it... "depends"... on whether I would recommend YOU to dive it... "nope"... and I say so because by asking the question you're stating you don't understand the dive or the dive plan... and that, in my book is a good foundation for "calling the dive" right out of the gate...
... no disrespect ment... just trying to give the best advise I can...
... my two pence.
The first dive is to be on a wreck in 120 ft
Second dive is a reef with what he describes as a shelf in 80 ft
Third dive is also a reef with sandy bottom in 80 ft
Yes I would, on nitrox, a minimum 1 hour SI, and I wouldn't remain at maximum depth during my whole dive. Quite often on these types of dives I hover 10 feet above my buddy to be more conservative, and I do a deep stop, and a safety stop. I tell my buddy ahead of time this is what *I* will be doing. Nothing wrong with diving with your buddy, but tell him ahead of time what minor modifications you will be doing.
Second dive is a reef with what he describes as a shelf in 80 ft
Third dive is also a reef with sandy bottom in 80 ft
Yes I would, on nitrox, a minimum 1 hour SI, and I wouldn't remain at maximum depth during my whole dive. Quite often on these types of dives I hover 10 feet above my buddy to be more conservative, and I do a deep stop, and a safety stop. I tell my buddy ahead of time this is what *I* will be doing. Nothing wrong with diving with your buddy, but tell him ahead of time what minor modifications you will be doing.
Blackwood
Contributor
Wait, that's conservative how? Is your buddy your decompression algorithm?
rstofer
Contributor
First, as to Nitrox: you could use EANx 30 for the 120' dive and EANx 36 for the 80' dives. You would want to be ABSOLUTELY CERTAIN you didn't use the tanks with EANx 36 for the 120' dive by mistake. I would use air for the first dive.
If there was some legitimate reason for diving to 120 feet, I would treat it as a square dive unless I had a lot of confidence in my computer. Since the EAD for EANx 30 is 103' the table entry would be 110' and the NDL would be 16 minutes from the time you start the descent until the time you begin a direct ascent to the surface. A 3 minute stop at 15 feet is required. I might stop at 60' for a couple of minutes and spend some additional time at 15 feet.
Remember, narcosis comes along at this depth. Using Nitrox is not a solution to this problem.
Since you come out as just an 'M' diver, plan to spend about 1:26 of SIT to get back to a 'B' condition - more is better, try for 2:00. Then from your handy EANx 36 RDP, your ANDL for the first 80' dive as a 'B' diver is 44 minutes with 11 minutes of RNT. Assuming you use up all of the ANDL then you surface as a 'V' diver. I might stop at 40' for a couple of minutes and definitely stop at 15' for at least 3 minutes. Plan to spend 2:00 (or more) of SIT to get back to a 'B' condition.
The final 80' dive is the same as the first. You have 44 minutes of ANDL and you exit the water as a 'V' diver.
I like the tables. But the examples above all hit the NDL. That's not a good thing. You might consider backing off on the bottom time and extending the 15 foot stops.
But this points out the futility of deep dives. If you descend at 60 feet per minute, it will take 2 of your 16 minutes ANDL to get to the site. If you decide to decrease your allowable bottom time by, say, 4 minutes (25%) for safety, you only get to spend 10 minutes on the wreck. What's the point?
If you are using a computer, fine. But I would start with these depths and times on a slate so that I could check the computer. Better yet, calculate the (A)NDLs for yourself. You absolutely don't want to depend on my work. Make sure you and your buddy agree on the plan - tables vs computer(s), etc. This should be decided long before you get wet!
Technically, there is no issue with this series of dives. I would extend the 15 foot stops and the SITs. I think I would use air for the first dive and EANx 36 for the last two. I would watch for signs of euphoria on the first dive.
If the first dive uses air, the NDL is 13 minutes (subtract 2 minutes for descent and 3 minutes for safety and you only get 8 minutes on the wreck). You leave the water as a 'K' diver and need 1:17 (minimum) to get back to 'B'.
As to the wisdom of these dives: Well, something must be wrong! You asked the question rather than just making the dives. Either you don't like deep diving (I don't), don't like planning deep dives or you don't trust your buddy. If the dives make you uncomfortable, don't make them.
But you should certainly have a written plan that doesn't rely on a computer. I have always written the (A)NDLs on a slate. But then, I don't trust computers.
This could be an excellent exercise for checking your computer(s) against a square profile using tables. The dives are so deep that you probably wouldn't be inclined to diddle around during ascent and try to turn it into a long multilevel dive. Even your computer will see it as a square dive with a little deco stop at mid-depth. A great exercise...
Bottom line: skip the dives and go for something more mellow. I like 30-40 feet. Lot's of neat stuff to see and enough light to see it.
Richard
If there was some legitimate reason for diving to 120 feet, I would treat it as a square dive unless I had a lot of confidence in my computer. Since the EAD for EANx 30 is 103' the table entry would be 110' and the NDL would be 16 minutes from the time you start the descent until the time you begin a direct ascent to the surface. A 3 minute stop at 15 feet is required. I might stop at 60' for a couple of minutes and spend some additional time at 15 feet.
Remember, narcosis comes along at this depth. Using Nitrox is not a solution to this problem.
Since you come out as just an 'M' diver, plan to spend about 1:26 of SIT to get back to a 'B' condition - more is better, try for 2:00. Then from your handy EANx 36 RDP, your ANDL for the first 80' dive as a 'B' diver is 44 minutes with 11 minutes of RNT. Assuming you use up all of the ANDL then you surface as a 'V' diver. I might stop at 40' for a couple of minutes and definitely stop at 15' for at least 3 minutes. Plan to spend 2:00 (or more) of SIT to get back to a 'B' condition.
The final 80' dive is the same as the first. You have 44 minutes of ANDL and you exit the water as a 'V' diver.
I like the tables. But the examples above all hit the NDL. That's not a good thing. You might consider backing off on the bottom time and extending the 15 foot stops.
But this points out the futility of deep dives. If you descend at 60 feet per minute, it will take 2 of your 16 minutes ANDL to get to the site. If you decide to decrease your allowable bottom time by, say, 4 minutes (25%) for safety, you only get to spend 10 minutes on the wreck. What's the point?
If you are using a computer, fine. But I would start with these depths and times on a slate so that I could check the computer. Better yet, calculate the (A)NDLs for yourself. You absolutely don't want to depend on my work. Make sure you and your buddy agree on the plan - tables vs computer(s), etc. This should be decided long before you get wet!
Technically, there is no issue with this series of dives. I would extend the 15 foot stops and the SITs. I think I would use air for the first dive and EANx 36 for the last two. I would watch for signs of euphoria on the first dive.
If the first dive uses air, the NDL is 13 minutes (subtract 2 minutes for descent and 3 minutes for safety and you only get 8 minutes on the wreck). You leave the water as a 'K' diver and need 1:17 (minimum) to get back to 'B'.
As to the wisdom of these dives: Well, something must be wrong! You asked the question rather than just making the dives. Either you don't like deep diving (I don't), don't like planning deep dives or you don't trust your buddy. If the dives make you uncomfortable, don't make them.
But you should certainly have a written plan that doesn't rely on a computer. I have always written the (A)NDLs on a slate. But then, I don't trust computers.
This could be an excellent exercise for checking your computer(s) against a square profile using tables. The dives are so deep that you probably wouldn't be inclined to diddle around during ascent and try to turn it into a long multilevel dive. Even your computer will see it as a square dive with a little deco stop at mid-depth. A great exercise...
Bottom line: skip the dives and go for something more mellow. I like 30-40 feet. Lot's of neat stuff to see and enough light to see it.
Richard
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