Timing of Dives

[fred32176]

I would not want to do that many dives in that short of period. It would seem like work rather than a vacation. Space out your dives, so you are always refreshed and eager for you next dive. On 3 - 5 day vacation to the keys, I do two 1/2 day 2 tank boat dives for a total of 4 dives. Stuff happens, conditions can be bad some days, Trying to cram in a maximum number of dives in a short period of time can be less enjoyable than having a more relaxed less hurried schedule. Last fall when we were in the keys, two dive days in a row were canceled because of conditions and my diving was shifted back two days. You need to be able to adapt to things you can't control. Be mellow and enjoy a margarita, your on vacation.

I did AOW in January, 5 dives in a weekend. 3 deep dives over 90' on Saturday and 2 dives on Sunday. After doing 5 dives in a weekend, I was happy to not dive for a week. Enjoy a dive, take time to refresh yourself and enjoy other stuff as well. Don't burn yourself out trying to do too many dives in a short period of time, it it is a vacation if you can do you deep dive cert, cool, but a card is not worth making a vacation less enjoyable.

 

[Angelo Farina]

We will be going to Cozumel in a few weeks and will be able to dive 4 days. We have to complete our SSI Deep Diving Specialty Diving certification so will need to do 4 deep dives. If we do two of those dives each day on consecutive days but also want to do 2 fun dives each day (so total 8 dives over 2 days), does it matter which dives we do in the morning vs afternoon? I vaguely recall reading that if you want to do 4 dives in a day, you do the deep dives in the morning and then the shallower dives in the afternoon. Is that correct? Also, would diving with Nitrox on the non-deep dives be a good idea?

If the deep dives are not exceeding 40m and well within NDL (reaching your safety stop with at least 5 minutes before hitting NDL), and you can use a proper Nitrox mixture also for them, at that point these are all "normal" recreational dives, they should not be classified anymore as "deep".
So you can do 4 in a 24h frame, for multiple days.
Of course the standard concepts apply: try to distance the dives as much as possible, start with the deepest one in the morning and then shallower and shallower.
Nitrox is great for all dives in this case, and the oxygen percentage should be adapted to the planned max depth of each, so you could start at 26% or 28% in the morning and end up at 40% for the last dive of the day.
Of course your compiter must be set properly for each dive, so it can track correctly the amount of residual nitrogen.

But if instead your deep dives are like MY deep dives, in air, reaching 50+ meters and with a few minutes deco, or riding the edge of NDL (which, as you should know, is even worse) then 4 dives a day becomes a dangerous stretch.
My training (which I admit, is a bit outdated) allowed to make only ONE shallow depth repetitive dive, after such a demanding first dive. And with a long surface interval of 4+ hours.
So you have a deep/deco dive in the morning, then wait, have lunch, some after-lunch siesta, and a single shallow dive in the afternoon (for which Nitrox can be in some way beneficial, but in this case it changes very little).
Probably with modern deco theory and procedures (which is not part of my training and expertise) it is possible to create a third intermediate dive plan, allowing for 3 dives per day, working on some additional safety buffers (GFs or the like), and perhaps employing two different gas mixtures in the deep dive.
But, as said, this goes beyond my knowledge, so I cannot comment on this.
In any case, I judge your program with two deep dives per day and 2 additional shallow dives each day too risky.
I would not do that, even if I was qualified for those advanced deco procedures with gas switching (which I am not, and from what you wrote you aren't too).
The only way your plan is feasible is if the "deep" dives are in reality not deep, less than 40m and with optimised Nitrox.

 

[DiveLikeAMuppet]

We will be going to Cozumel in a few weeks and will be able to dive 4 days. We have to complete our SSI Deep Diving Specialty Diving certification so will need to do 4 deep dives. If we do two of those dives each day on consecutive days but also want to do 2 fun dives each day (so total 8 dives over 2 days), does it matter which dives we do in the morning vs afternoon? I vaguely recall reading that if you want to do 4 dives in a day, you do the deep dives in the morning and then the shallower dives in the afternoon. Is that correct? Also, would diving with Nitrox on the non-deep dives be a good idea?

On a more pragmatic note, there are two ways to teach a Deep diving course.

One is a guided excursion. Simply drop to the target depth for a minute, do the minimum number of skills required (usually something simple to see how impaired are you at depth) and then continue with the dive shallower. Easy diving, pat on the back at the end, another card, no new skills learned. In this case, four dives would be perfectly fine.

Another way is to treat the deep dives as "bigger" dives. So a proper briefing and dive plan (prepared by students), equipment check, drop down to target depth, track your gas consumption (planned/expected vs. actual), maybe some wetnotes math to see impacts of nitrogen narcosis. React to one or two emergencies on ascent, deploy a DSMB (each student) and hold a simulated decompression stop. Theory should include nitrogen and CO2 narcosis, basic problem solving, dive planning and what happens when you put your computer into deco. A good debrief after each dive. Some of these skills might be new or need reinforcing, so lots to learn on the course - which is a good thing.

If you get lucky with a good instructor to get the proper course (or if you kick your instructors butt to get it), you will learn a lot but you would be quite tired at the end.

 

[L13]

I would think the main problem with 4 dives/day from shore would be that with roughly 1 hour dive time and 1 hour SI this will add up to 7 hours at a minimum and the whole thing will feel like work rather than "recreation".

On my last vacation to Cozumel, I did 19 dives in 4 days. It was one of the best vacations I've had, nothing like "work". But not everyone enjoys the same things. I happened to be with a buddy that had just as much fun doing this as I did.

On my second best vacation to Cozumel, I did 6 dives in a week. My buddy that time only did 4 of those dives (different buddy), and we again had a great but different vacation. It wouldn't have been as good a vacation if I had pushed for more dives.

Don't be too sure you will enjoy doing 4 dives a day for 4 days. It is a lot and most people don't enjoy it as much as they think they will. You don't get much beach time if your are doing 2 boat trips a day.

If it is your first time, I would plan only 1 morning boat trip (2 dives) the first day, with an optional shore dive after if you are feeling it. Then after that, if you are still feeling it, you can up your next few days to 2 boat trips (4 dives). I would only do 1 morning boat trip your last day of diving, unless you are taking a complete day off after before flying.

To qualify as "Deep Dives" for certification, I believe the depth must be >60ft. Most of the good boat dives in Cozumel will start at least that deep. Many will go to >80ft. Though it will depend on the average experience level of the divers on your boat. Some dive ops that focus on newer divers never do dives deeper than 60ft.

If you are doing 4 dives per day in Cozumel (especially if you are doing the deeper dives) for more than a few days, you should use Nitrox otherwise you will be hitting your NDL limits on the last days.

 

[Pulmcc]

perhaps consider doing a 2 dive morning trip each of the 4 days (deep first dive / shallower second dive). then add in a really shallow shore dive in the afternoons?

i personally would not be doing 4 dives in a day.

nitrox never hurts as long as you are within your max depth. you can also dive nitrox but plan your dive time as if you were on air for extra conservatism.

my wife and i did this whenever i was on nitrox as she was never nitrox certified and was on air.

We did 4 dives a day when we were getting certified on a liveaboard but those were not deep dives obviously. With the shop that we are using in Cozumel, they always go out on 2 dive trips so it's either 2 in a 4 or 4 in a day. The morning pickup is shortly before 9 and the afternoon shortly after 2 pm so a 3-hour surface interval between morning and afternoon.

 

[Pulmcc]

The order of the dives doesn't matter but if you are using certain computer brands and algorithms (Suunto and RGBM), you might get a very low no-stop time on the subsequent dives if they are deeper, as these computers tend to punish you for reverse profiles.

Your deep dive course should include a bit of theory that would explain why it would be safer to limit yourself to 2-3 dives per day at these depths with sufficient surface interval.

Nitrox is always a good idea, especially with many repeated dives, just pick the right mix for the right dive site.

We have Shearwater Peregrine.

1 hour SI between dives, 3 hours between morning and afternoon sessions.

 

[L13]

We did 4 dives a day when we were getting certified on a liveaboard but those were not deep dives obviously.

A bigger difference than the depth is the time consumed loading on and off the boat, and the trip to the dive site. 2 boat trips a day doesn't leave much time for relaxing on the beach. That maters more to some than others.

With the shop that we are using in Cozumel, they always go out on 2 dive trips so it's either 2 in a 4 or 4 in a day. The morning pickup is shortly before 9 and the afternoon shortly after 2 pm so a 3-hour surface interval between morning and afternoon.

That is the normal schedule for most shops in Cozumel. The morning boat won't be getting back to the dock until almost 1 pm. The afternoon one won't be getting back till after 5 pm.

 

[Pulmcc]

If you are diving with the same op for all of your dives, including the course, I would expect that your instructor or the shop will keep in mind which sites to go to for your dives. In Cozumel there is quite a variety of depths available.

For the SSI deep specialty, not every dive is super deep. A Google search returned these results of the depth range for each dive in the SSI Deep Diver Specialty.

• Dive 1: 18 to 30 meters
• Dive 2: 24 to 30 meters
• Dive 3: 30 to 40 meters

I Cozumel, the Nx options are 32% and 36%, so Nx is definitely a good idea for most of these. For your deepest dives, you will need to dive air.

Yes, going with Salty Endeavours our entire trip.

When we are in French Polynesia last year, we averaged 20 m during our dives. We went down a little further to 25 m once but didn't notice any difference.

 

[Pulmcc]

Four dives in a day is quite a bit of diving and you will want a decent surface interval between the two deep dives. Three dive in a day and an option on night dive would be what I would do. Nitrox will be good for the shallow dives. If you are in good shape I think it will be fine, but if you aren't, I would avoid making it too demanding.

Saving our night diving for Maldives in July. The place we will be staying at there offers night and fluorescent night diving so figured we would try that.

 

[L13]

I Cozumel, the Nx options are 32% and 36%, so Nx is definitely a good idea for most of these. For your deepest dives, you will need to dive air.

Why would you need to dive air on the deepest dives?