I think of them as passion points!!!! And I am very passionate about my diving;)
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I think of them as passion points!!!! And I am very passionate about my diving;)
I definitley agree with getting the proper training portion of your post papa. However, in a perfect world everyone would be diving the same tanks, this isn't the case however. When planning ANY dive turn pressures/volumes should be calculated based on the person with the smallest amount of breathing gas and/or the highest sac rate.Quote:
Originally Posted by Papa Bear
I'm not a cave diver..........yet, but I have heard of cave divers re-calculating 3'rds/6'ths and heading back in for a little jaunt in the cave so I'd say these folks are heading in with a less than full gas supply. For any overhead diving, the team should be configured the same with redundant gas supplies, proper training.
If I am in A OH environment with a diver with a 63 and their sac rate is great and they get into trouble we have no problem, unless I screw up, but if have a problem and have to put my life and theirs on whats left in their tank we have a big problem. It happen in Caving where the team is H & W or B & G and one sets up with twin 72s or 80s and the the hog sets up with 105s or 120s! The trouble is on the horizon, what happens if you just before turn around and the hog has a major problem with the air supply? Is 2/3rds of a set of 72s enough to get both of you out? Maybe, and I am not putting my life on the line for a maybe! Never go in an Overhead environment unless planned and with the amount of air you planned on! So its not about her or her sac rate, its about the dive, and where your going and what your doing!
from the sounds of it maybe some proper overead/dive planning training would be in order for you;)
Really? Why do you say that? I was trained by Bill Rennaker and John Orlowski can you think of any two that are better? If you have some constructive criticism of my explanation then post it! Otherwise I don't see the reason for your statement? Even with a wink? You lost me some where deep in the cave I guess? Or maybe its your rant?
now who needs to lighten up ROFL
I have been working on that! Yo Momma! :p
SAC rates have no affect here, you simply calculate your turn pressure based upon the minimum capacity within the group. If diver A starts the dive with 90 cuft and diver B starts with 250 cuft, diver A's supply would dictate turn pressure, in this case 30 cuft. Convert that back to PSI and note your turn pressure. Thus both divers are limited to using 30 cuft of gas before turning the dive. It makes no difference who has the highest SAC rate, as when the number is hit by either diver, the dive gets turned. Nothing at all wrong with recalculating as long as you adhere to your rule of thirds (the dives will be shorter in duration, but just as safe.) :)Quote:
Originally Posted by scuba smurf
You make use of your SAC rate to determine the minimum gas requirements for your dive. If you want to dive to x feet for y minutes, you would make use of your SAC rate to determine how much gas you will need to accomplish the dive. You would then calculate thirds as usual, with no reference to individual SAC rates.
Thanks Bama, my bad, you explained it much better
Bama, you did make it simple! You did a better job of explaining it than I did! Thats for sure, but the out come is the same! ;)
Of course I carry enough air for my buddy! & yes, we follow the rule of 3rds & dive our plan. Whoever first uses 1/3 of their starting supply & we turn back regardless. I do agree with you about the pitfalls of H&W, B&G buddies, so that is why planning is important. In a perfect world, we would be buddied-up with those who have the same dive-style, SAC rates, air supply & gear. [I think we're starting to get into DIR territory here....]Quote:
Originally Posted by Papa Bear
& for an overhead environment, I would not buddy with a known hog, or potential hog (aka he/she-who-becomes-a-hog-when-conditions-are-less-than-ideal). In my limited experience, I've seen such individuals not follow basic rules/common sense much less the rule of 3rds b/c they are so focused on trying to entend their time/depth/range with little thought of the consequences. These are the same people that routinely ask for air at the bottom of the line & surface at barely 500psi. These are the people I'm kvetching about.Quote:
Originally Posted by Papa Bear
& as for diving in an overhead environment with a 60cuft remaining air supply & a buddy with 120cuft - now what is the point in that?
Quote:
Originally Posted by littleleemur
Now there is nothing wrong with surfacing with less than 500psi if the site and conditions allow.
Two points, one overhead and the other open water! In open water my feeling as long as your breathing when you hit the surface you have enough air! Overheads a lot different! Requires planning and understanding of all the factors!
If a woman has a sixty and her buddy (male) goes in on 120 if stuff hits the fan with her no problem, but with him big problem because she has to have enough to get both out! She won't! In overhead you have to carry enough for your buddy otherwise go solo! If she has 120 and he has a problem then there would be plenty of air to get both out! A miss match in overhead does spell potential disaster! If you share usable are on the bottom I see no problem at all and if they end with 500psi its 500psi they didn't need!
Note the OP is from Canada. I'm not sure how litigious that country is compared to the US.
Unless I planned a very short dive to retrieve something, I always prefer descending with a full tank. Over the 47 years I've been diving, I've had enough situations where a partially emptied tank might have made the dive less safe. Having said that, I used to do two, sometimes three dives off one HP120 tank.