Do you mean you won't be bringing your laptop, or your dive computer? I hope not the latter! There are internet cafes around which will enable you to get your www fix if you need it.
The reality is that you won't be in charge of your diving profile, your dive guide will be. I'll be surprised if your first dives of the day, after the first, are as shallow as 70ft. The BH dive is generally to just above the shelf, so you will probably go to around 145ft. How long they'll be I can't say, but I've seen dives where the divers were at 130-145ft for 10-12 minutes (not including the time of descent), so way beyond recreational limits on both depth and time. My computer has gone up to 40+ mins of deco in those circumstances, but the customer divers haven't had computers. I usually find myself limited by available no-deco time on the subsequent dives, though again the divers haven't known that as they haven't had computers. On all three dives on that day I strongly suggest you DO carry your own computer and that you stay around the "safety stop" depth for 10-15 minutes, or longer if your computer tells you to. And avoid any alcohol from the evening before to the morning after - don't drink alcohol on the boat on the way back, even though most other people may.
Your breathing rate doesn't particularly affect your nitrogen absorption, though it has a considerable effect on how long your tank will last. I don't understand what your reference to "SI" means - I know what the letters mean, but not the reference. Don't forget that your breathing rate will be greatly affected by what you are doing underwater - easily rising by a factor of 7 or more when you're working hard or very stressed. Too many inadequately trained recovery divers have paid with their lives for forgetting that basic fact. Of course your nitrogen absorption is mostly affected by your depth.
I hope the dives are conducted in a way that enables you to get decent photographs. Have you done much U/W photography?
---------- Post added at 12:31 PM ---------- Previous post was at 12:25 PM ----------
All of which is in the manual as is the cardinal rule that you, the diver, are ultimately responsible for your own safety, which is why you must have a way to verify the blend so you can plan accordingly.
As in, bring your own analyzer if your shop doesn't have one.
Can't agree more. I had several analysers for customers to use when I ran my tech dive shop and if I were now running a shop I would always have at least two. I don't understand how anyone can run a dive shop and NOT have an analyser, though I do know that very few shops here DO have them. Perhaps it's just another hidden way to reduce costs, like not having proper insurance or contributing to the local Chamber, or skimping on maintenance of boats, compressors and tanks. Customers rarely ask up-front, and by the time they learn the hard way it's too late. Analysers are quite expensive toys and once unsealed are time limited, so they make more sense for a shop than for the individual diver. Though when I dived recreationally around Britain years ago, long before I ever got into the business of diving, I always had my own. Once I started diving trimix I also had a helium analyser - now that IS expensive. My last one was lifted by a staff member in my dive shop, and I've never bought one since.
---------- Post added at 12:45 PM ---------- Previous post was at 12:31 PM ----------
Yes I have; however, for me, if I don't use it I lose it. I need to go back and do some intensive review before diving in Belize.
On another note, since you are familiar with a number of dive shops on AC, do you know if they have analyzers available to test air and Nitrox? The more I read on other forums about having one's own analyzer, the more I think I should buy one for air and Nitrox. Comments?
If you learned to use the sorts of formulae that PADI have in their text book, I'm not surprised you don't retain it. That's learning by rote, not comprehension, and it never works. Understand the principles which are very simple, and then work everything out from those principles. Once you've done that a few times you'll never forget it, and far more to the point you'll UNDERSTAND it.
I covered the point about available analysers above. If you dive at all frequently (or even if you don't!) - if you dive nitrox, get your own analyser. It's also a good idea even for air diving - in fact expecially for air diving - to get a carbon monoxide (CO) sensor. A compressor system designed to produce nitrox should have appropriate filters with checks in place to prevent significant levels of carbon monoxide, but be very suspicious of a cheap (small) compressor being used to pump air, especially if the operators don't seem to know much about the subject. It is PROBABLE that unsafe levels of carbon monoxide are being put into the tanks. There's nothing you can do about it - if there's more than a very small %age of carbon monoxide in the tank don't use it, and don't use any other tanks filled from the same compressor. Remember - there's only one letter's difference between DIVE and DIE. I once checked over a compressor installation that too often (but not always) produced bad air. I discovered that they were using a diesel motor to drive the compressor, and the exhaust was too close to and often upwind from the air inlet. Very often the problem is unintelligent installation rather than some intrinsic fault with the equipment. With an compressor driven by an electric motor that doesn't arise, but if the compressor is situated on a dock there's a very real risk of sucking in exhaust from boat engines - or sometimes just people smoking too close to and upwind from the air inlet.
