A lot of real world diving is
guided diving, often in places the divers aren't particularly familiar with (& may be diving one time in their lives). And multi-level diving at that. Often a 2 tank trip diving AL 80 cf tanks, likely with an instruction to not go over a given depth (if the site doesn't have a hard bottom preventing that, like many reef sites at Key Largo). The guide is leading a group of divers, has to plan conservatively to avoid anyone running out of gas well out from the boat, and leads groups often enough to have a good handle on how to make this work.
The customer knows what region of the world is involved (e.g.: Grand Cayman) & maybe a site name. He's likely new to the site & probably doesn't know in advance how much of the dive will be spent near max. depth, etc
And if he's a good auditory learner with good retention on hearing it once, the briefing given right before gearing up & jumping in will still be a bit hard to effectively digest.
This guy is probably not going to pull out tables or try to get his computer into a dive planning mode. His odds of being NDL limited are quite low. His gas he'll watch on-the-fly as he goes through the dive, likely signaled by the guide intermittently to communicate his remaining supply.
This would be an unfamiliar dive to the likely limits of recreational depth or NDL. A recreational dive that I would formally plan would be if I ever actually get to dive the NC coast.
Yes,
on my trip I encountering potentially NDL limited diving, which I seldom do. Even there, diving with Olympus Dive Center, a few others factors came into play (which you might even call a form of planning):
1.) I dove a Faber steel 120 cf tank with EAN 30 to extend bottom time.
2.) There was a hard bottom (sand), typically around 120' or so.
3.) A mate drops down to tie off the anchor to wreck, and uses a wreck reel to lay a colored line & show a path divers can follow if they wish. Some wrecks are in pieces and navigation can become an issue if you get off the main 'piece,' or the wreck is really large.
4.) I still paid for a guide (money well-spent).
None of this is what many people think of as planning. But from dive op. selection to which services/gear one pays to use, there's more to planning than just advance planning of NDLs at a max. depth.
Richard.
---------- Post added August 24th, 2015 at 04:39 PM ----------
It would appear that when it comes to dive planning... the majority of recreational divers are simply winging it or doing trust-me dives.
Here's an idea for a simple poll on an important topic related to your current study. How confident are you in your navigational ability?
I suspect the prevalent level of navigational competence in the larger rec. diving community would fall short of what the forum membership would hope. It's a weakness of mine. For example, would you...
1.) Always rely on a guide or buddy to navigate, or stay very close to a major landmark, such as an anchor line or small wreck, or in sight of the boat?
2.) Willing to run a short range reciprocal course?
3.) Willing to run a longer range reciprocal course?
-----2.) & 3.) assume no significant current to compensate for.
4.) Willing to run a simple geometric shape (e.g.: square), but crudely (e.g.: using set compass bearings like 90 degrees, 180 degrees, 270 degrees, 0/360 degrees, a set steady finning or time frame each leg of the journey,
no deviation from the plan, don't go far & nervous the entire time, will little observation of reef, wildlife, etc
?
5.) Capable of comfortably running a square or rectangular pattern with moderate ability (e.g.: stick to the plan but enjoy the scenery, or able to use 'non-right angle bearings')?
6.) Capably run simple geometric patterns while maintaining good situational awareness, can modify the plan for conditions & desire, generally have a pretty good idea where you are with regard to the boat. Stopping, changing finning speed or other such things don't throw off your execution too much.
Somebody who's not level 5.) or higher is likely relying on a guide or buddy. Aside from a pre-agreed max. depth & maybe turn pressure, and some pre dive discussion (e.g.: I'm an air hog, I like to dive shallow), there are limits to how much planning they can do since they're following someone else around.
Richard.
