Is this doable?

[AceszHigh]

This saturday I am trying to do four boat dives, but the tables only go up to three repetitive dives. Here's what the schedule would look like, and I am wondering if this is safe enough to do.

My LDS banks 36% nitrox (which I'd be using on all dives), but if i really needed to I could probably get a higher mix

8:30am - 1st dive, max depth 80fsw (probably about 40min of BT)
~1 hour S.I.
about 10:30am - 2nd dive, same thing
~2 hr S.I.
1:30pm - 3rd dive, max depth 70fsw (about 50min BT)
1 hour S.I.
3:30pm - 4th dive, max depth 70fsw (about 50min BT)

I'm sure there has to be some kind of calculator on the internet somewhere for this type of thing..but anyways, input would be appreciated!

 

[SailNaked]

Tables only go up to three repeat dives? what does that mean? is it doable, I do not know I will have to go look at my tables.

 

[Thalassamania]

I know of no tables that stop with a dive and then two repetitive dives. What tables are you talking about?

 

[SailNaked]

Ill go out on a limb here.
your OTUs are fine, your CNS% is fine. you may need a bigger tank, would depend on your SAC. Unless there is something about tables that I did not learn I see no problem using them for this. what are you asking? do it if you feel it is safe I might be wrong and it might not be doable, who knows, I certainly do not. you are responsible for your profile.

 

[overkillphil]

Are you using a computer? If so, it will correct for multi-level diving, and give you a more accurate play by play. Plan by the tables for extra safety, but unless you are diving square profiles, it won't be very accurate.

 

[Bubbletrubble]

I find the initial post troubling. Perhaps the OP should consult the instructional materials from his nitrox class. The answer should be clear. AceszHigh, when you get the chance, please let us know which tables you are using.

 

[Eric Sedletzky]

This is what the PADI 36% tables say:

If you are doing square profiles you would be a little over on a couple of the dives with the info you provided.

The first dive is fine. With only an hour out you would have a 37 minute max on the second dive. If you stayed out 1.5 hours you would be allowed 41 minutes on the second dive. Staying out for 2 hours after the second dive would put you in pressure group B which is fine for the third dive. One hour SI after the third dive is not enough to do 70 feet again for 50 minutes, you would have to give it another 10 minutes on the SI, then you would be allowed 52 minutes.

Me personally, if I was doing these dives on tables, I would depth average unless they are indeed going to be square profiles, and I would also include a few deep stops and extend out my 15 foot stop as long as gas allowed.

 

[gcbryan]

I'd drop one of the dives and/or cut back on some of the times/depths for the later dives.

Sometimes "undeserved hits" aren't all that undeserved.

 

[AfterDark]

This saturday I am trying to do four boat dives, but the tables only go up to three repetitive dives. Here's what the schedule would look like, and I am wondering if this is safe enough to do.

My LDS banks 36% nitrox (which I'd be using on all dives), but if i really needed to I could probably get a higher mix

8:30am - 1st dive, max depth 80fsw (probably about 40min of BT)
~1 hour S.I.
about 10:30am - 2nd dive, same thing
~2 hr S.I.
1:30pm - 3rd dive, max depth 70fsw (about 50min BT)
1 hour S.I.
3:30pm - 4th dive, max depth 70fsw (about 50min BT)

I'm sure there has to be some kind of calculator on the internet somewhere for this type of thing..but anyways, input would be appreciated!

If you need to ask maybe you should rethink it or at least think a little more about it.
As stated eariler you need to know on your own for sure, it's your a**.

 

[scubadiver888]

This saturday I am trying to do four boat dives, but the tables only go up to three repetitive dives. Here's what the schedule would look like, and I am wondering if this is safe enough to do.

My LDS banks 36% nitrox (which I'd be using on all dives), but if i really needed to I could probably get a higher mix

8:30am - 1st dive, max depth 80fsw (probably about 40min of BT)
~1 hour S.I.
about 10:30am - 2nd dive, same thing
~2 hr S.I.
1:30pm - 3rd dive, max depth 70fsw (about 50min BT)
1 hour S.I.
3:30pm - 4th dive, max depth 70fsw (about 50min BT)

I'm sure there has to be some kind of calculator on the internet somewhere for this type of thing..but anyways, input would be appreciated!

You could try to find an online planner for air then use something like the DSAT cards for EAN. They have tables for converting EANx to air equivalents. e.g. 80fsw on EAN36 is equivalent to 59fsw on air (EAN21). You can then plan the nitrogen loading using an air planner. You'll also have to calculate the O2pp as well.

I'd still do the EAN36. If the MOD is 80' then you can go to EAN40 but (a) what if you go a little deeper by accident or have to go deep to save your buddy and (b) I'd worry more about an oxygen toxicity than nitrogen loading.