Fist time I called a dive at depth...

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Diver0001:
I've been thinking about this. It sounds to me like you're trying to make the descent too deep. If you're not supposed to make a descent to more than 20 metres without supervision then making one to almost 30 without a reference isn't a good idea. I think you should make your descent to 18 metres and work down along the bottom from there. Maybe this can be done without a reference but I still think that rigging a shotline is possible and a good idea.
I completely agree. And it is what we have decided with the course director, to do my next deep dive at a site where we are not obliged to dive that way.

Diver0001:
In terms of setting the shotline you don't want to have a dedicated team to do that and (this is the part I've been thinking about) you don't want to have to use too big of an anchor.

My idea is to still use a 20 kg float but instead of a grapnel use a 10kg anchor. You can rig it as follows: Under the float hang a long line, almost twice the length to the bottom, along a series of rings or caribiners, using a weight like maybe a couple of 2 kg scuba weights to keep the line straight enough to use as a reference. That way the anchor will stay on the bottom even if the float get lifted by a wave (ie, you don't need to set it) and you'll have your reference for descending. You'd have to remember to grab both parts of rope if you needed to hang from the float but this is a workable solution for a zodiac as long as the surface current isn't ripping.

I don't know if you can follow what I mean from my description so PM me with your email address if you want me to draw you a picture of what I mean. If you're not interested we'll leave it at that.

One word of disclaimer. I'm sure I could get this to work but it may take a little refinement.

R..
Thanks for your proposal of help, but as I won't be in charge of the setting, I think that wel leave it at that. Nevertheless, I will discuss it next time I dive there (surface current is always ripping at least a little bit, remember, huge tide heigths in the Channel between Atlantic and Mont Saint Michel)
 
^*^BATMAN^*^:
just check your bouyency before your next dive, at the surface, with you BC empty, you should float around eye level with full breath, when you exhale, you should start sinking, then you are properly weighted. Also you need to be adding little bits of air to your BC the whole way down to stay neutral, but you seem to know this so.....

I know bouyancy is important, but after you've done it the PC (PADI Correct) way, it would seem better to fine-tune this by checking at 15ft, at the end of the dive. I carried some of my lead in the BC pockets, and at the 15ft level, with about 750PSI left in the tank, proceeded to let all air out of the BC. I took one pound out at a time. If I was still sinking, one more pound. I found at what point I became neutrally bouyant at 15ft. That is what I dive with when using Aluminium tanks. Checking at the surface doesn't take into account the change in bouyancy in the tank itself, and the effect on the diver, by the end of the dive. Anyway, I dive steel 12L most of the time (3500PSI). Do a rough bouyancy at the surface, I guess, but I prefer fine tuning it my way.
 
Jeddah Aquanaut:
I know bouyancy is important, but after you've done it the PC (PADI Correct) way, it would seem better to fine-tune this by checking at 15ft, at the end of the dive. .

Since about a year ago I've started to hear a lot of people saying this. In my opinion you need to be able to control your ascent *all* the way to the surface. If you don't then you'll be making a buoyant ascent through the last (most important) 15 ft of every dive.

R..
 
Diver0001:
Since about a year ago I've started to hear a lot of people saying this. In my opinion you need to be able to control your ascent *all* the way to the surface. If you don't then you'll be making a buoyant ascent through the last (most important) 15 ft of every dive.

R..

Right, what you don't want to do is shoot to the top. You also don't want to drift upwards to the surface because you're underweighted. If you are diving with Aluminium tanks, your bouyancy is going to be affected by several pounds by the end of the dive. You might float at eye level on the surface at the beginning, but that will not do you at the end. That's one reason why I like my steel 230 BAR tanks. Regardless, I always carry a few extra pounds, either two 1lb softies or a clip on 2lb, since I often am with friends who have newbies, and often they need a few extra pounds by dive's end. I still get plenty of dive time, and my bouyancy is fine. Regardless of how one weights up at the beginning, all divers need to better tune their bouyancy towards the end of a dive. A few pounds extra won't hurt, but if you've got 4 or more pounds of extra lead you're carrying around,....Why? Anyway, that's what I do.
 
Bretagne:
<SNIP>

A N4 is not a professionnal, but it is a necessary stage to become professionnal.

<SNIP>

While not entirely on topic, that statement is not entirely true: a N3 can commence on his BEES and become professional.

It's probably true that the french FFESSM do not allow you to go from N3->MF1 -- but then again, an MF1 is *not* a professional (he's an instructor, but only allowed to act in clubs etc. without getting paid)
 
divenut2001:
Your DM did not make a mistake by not letting you put air in your BC. He probably felt you were on the verge of panic and wanted to control your ascent so you didn't bolt to the surface. It's too difficult to control 2 BCs and prevent a run away ascent. Once he got you to a shallow depth and felt you could handle it he let you go.
You were NARCED...:)

Yes, Bretagne might have been narc'ed, and the N4 (as such) did correctly in "taking over" to finish the dive safely. While I write "correctly", this is one of my big(gest) issues with the French system of diving instruction: that essentially, all dives are "trust-me-dives" -- or, at least, that's the impression that it seems to leave on many divers.

I do have an issue with what method was used to egress Bretagne: the N4 essentialy used his BC as a lift-bag for both divers, which could have had dire concequences. What if something had caused the N4 and Bretagne to loose grip of each other? If the N4 controlled bouyancy through only venting his own BC on ascent, he would sink (but probably could swim up) while Bretagne (who wasn't actively in control of the bouyancy) might do the polaris-misile-ascent. Or, alternatively, if the N4 completely vented the BC of Bretagne and used his BC for lift: should the grip slip, he'd polaris to the surface, and Bretagne would sink like a rock.

When I egress a a diver from depth, I try to ensure that he's neutral and I'm very very slightly negative (and slightly finnng) for the ascent. Should the grip slip, noone would sink or bolt. (And the chances of a grip slipping would be less, since there'd be nothing pulling up or down).

I agree that controlling two BC's at once is more complicated than controlling just one. However it's easilly learned (pratice, pratice, pratice,...) and something which an N4 definitely has been through in his training.

Anyways, enough ranting. Bretagne, when're we going diving together -- seeing as we're both in France :)
 
Bretagne:
Mike, for now, I have felt that I need less weight because my wet suit does not yet regain as much volume as I went up. But it could change when it gets older and get more permanent compression, I do not say that it is a general rule. Nevertheless the difference is not very huge.
It is from the difference when I reach the surface that I have felt a need of less weight, not from the behaviour at the bottom.

It makes no sense that your suit should magically loose bouyancy when ascenting after a deep dive -- at least, I cannot find any rational explanations that would make sense. Nonetheless, you feel what you feel, so let's assume that the hypothesis is correct about your suit.....

In that event, always plan for contengencies: you should be weighted such that you can hold your stops, even if you should find your suit at its "most floty". So I'd reccomend -- as have others -- that you do the weight-check with an almost empty tank.
 
wolf eel:
I agree with you. I know they are not students but they are in essence as you must dive with a n4 rating or better to dive that deep. Or prove with logs that you can.

The law may not be literal law but I think it has too do with insurance and rescue costs.

Ontario is trying something like it soon Quebec already has a Provincial dive law. I think it limits where and how you can dive by your logs.

Cheers
Derek

Quick tutorial on the French dive system, which is indeed litteral law.

The french dive law covers all diving in structures (clubs, shops, ...), but not diving "between friends".

By law, in France, there are 4 levels of "divers" and 4 levels of "instructors":

Divers:

P1: ~Padi Scuba Diver. Can only dive with a P4 or instructor, limited in depth
(<20m, I think), and a "directeur de plongee" (dive director) on the surface.
No/very-limited table/deco understanding.
Dive parameters fixed by the dive director and ensured by the P4.

P2: Independant to 20m, guided by a P4 to 40m. Always with a "dive director"
on the surface.
Limited table/deco understanding.
Dive parameters fixed by the dive director and ensured by the P4 (if present)
or the P2's (if diving independantly).

P3: Independant to 60m. No guide needed, no dive director needed.
O2 deco and surface O2 deco is taught.

P4: Like P3, but can also act as "guide de palanque" -- dive guide.

Sometimes, you see P1, P2, P3, P4 written as N1, N2, N3, N4 too.

Instructors"

E1: diver P2 with a small "instructor course", that allows instructing basic skills
E2: diver P4 with same course as E1 -- CMAS * instructor. Can't certify students.
E3: Can teach & certify P1-P3 independantly. CMAS ** instructor
Can act as "dive director"
E4: Can teach & certify P1-P3 independanty. Can also teach P4, E1, E2, E3 --
but certification/exams for these levels are centrally organized through
an incomprehensible hierachy of comittes.
Can act as "dive director".

There are a couple of extra wrinkels in the system (a P5 exists somewhere, a level over E4 exists too etc), but the above is the essence of the system.

Anyways, a P2 with 500 logged dives to 60m outside of France cannot, within the French system, be taken to depths beyond what's outlined in the above.

Cheers,
 
Bretagne:
<SNIP>

I never turn on + on surface, otherwise there is a huge risk of free flow. I usually turn it in the first meter down, this day I forgot. At small depth it is of no consequence, I breath easily on -.

<SNIP>

I dive essentially the same reg (Aqualung Legend LX Supreme). If at the surface you're being careful to put the mouthpiece such that it faces downwards, you should have no freeflow-problems.

Also, if the reg is correctly maintained and functioning, even in the - position, you should breath easilly at depths much greater than 40m.
 
Bretagne:
A steel tank is always negative.

Yes, but it's less negative at the end of the dive when it's empty, than it is when it's full of gas. That's why you should do your bouyancy/weight check with an empty tank.
 

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