Don't know what happened

[scubadada]

Ok, how much weight do you take on that dive you just finished then?

You quickly learn how much weight you need for the exposure protection that you are using and the cylinder you are using. I generally use a rental AL 80. With my 3 mm, I use 8 lbs, for my 5 mm, I use 14 lbs, for my 7 mm, I use 20 lbs. Works perfectly, I'm a little heavy, but that's better than being too light. I often dive with a 5/3 mm hooded vest with each of the above.

 

[Coztick]

You quickly learn how much weight you need for the exposure protection that you are using and the cylinder you are using. I generally use a rental AL 80. With my 3 mm, I use 8 lbs, for my 5 mm, I use 14 lbs, for my 7 mm, I use 20 lbs. Works perfectly, I'm a little heavy, but that's better than being too light. I often dive with a 5/3 mm hooded vest with each of the above.

Wow.
The question was assuming you Needed to do a weight check.
Let's pretend you're helping a new diver in unfamiliar gear...
How do you determine how much weight he should carry when tanks are full?

 

[David Novo]

Wow.
The question was assuming you Needed to do a weight check.
Let's pretend you're helping a new diver in unfamiliar gear...
How do you determine how much weight he should carry when tanks are full?

The way you mentioned is a good place to start but does not replace a buoyancy check to confirm in the end (for a reference for future dives).

 

[Coztick]

The way you mentioned is a good place to start but does not replace a buoyancy check to confirm in the end (for a reference for future dives).

That's the goal. A safe amount to start with. It should get you within a few pounds. Some of us account for a complete loss of gas or a buddy needing a few lbs.
Tune as you like but you have to start somewhere safe.

 

[poseident]

to the OP....

I skipped most of the thread since it got heated. Up to the point where I skipped, I didn't see your profile/body position mentioned. It sounds like this was a wall dive. Walls usually have current. You want to be as close to "horizontal" as possible. The more "upright" you are, the more the current will push your body. If going against the current, that can significantly slow you down. If going WITH the current, it can help you. So "---" not "/" is usually what you want.

Not to be indelicate, but body size is also a factor here. More girth means more water resistance, so take that, or ignore it if you are blessed to be thin at 69.

Also the points about kick are probably worth investigating. Most people with really inefficient kicks have NO IDEA their kick needs work. As for fins, that's a touchy topic. If you were all in the same/similar fins, then technique or body position is more likely the issue.

But, there are some fins that exacerbate certain kicking issues. I almost exclusively frog-kick, and prefer fairly "normal" long-ish paddle fins. I've had good luck with certain split fins, but others just don't work as well for me. I've tried ForceFins multiple times, and they just don't work for me at all. Everyone's mileage varies.

Good for you asking questions. You might want to do a dive with a different instructor and ask feedback. The group of instructors I used to teach with would "rotate" Divemaster candidates for the express purpose of "pointing out issues" that the candidates "usual" instructor had missed. There was always something that could be improved, and nobody took offense. If that advice isn't practical, on every dive, pick who looks the best in the water and who ends the dive with plenty of air. Those folks probably have decent technique to emulate, whether they are pros or not.

Good luck!

 

[Dody]

Really, that was not such a big issue. After that day, I did 4 dives. I systematically did a buoyancy check at the beginning of the dive but the result was not what was expected. My head was submerged with 6 kg and exhaling but I could not descend until I had 8. It’s not a big deal really. It is just that the pre-dive check seems to be not reliable. But doing the check after the dive does not seem logical to me either.

 

[diver0008]

Really, that was not such a big issue. After that day, I did 4 dives. I systematically did a buoyancy check at the beginning of the dive but the result was not what was expected. My head was submerged with 6 kg and exhaling but I could not descend until I had 8. It’s not a big deal really. It is just that the pre-dive check seems to be not reliable. But doing the check after the dive does not seem logical to me either.

Pre-dive weight check works fine if you do it properly. As does proper finning technique and trim for efficient swimming. Keep diving; you will figure it all out for yourself eventually, like everyone else.

 

[scubadada]

...It is just that the pre-dive check seems to be not reliable. But doing the check after the dive does not seem logical to me either.

You should rethink that. At the end of the dive, you have used up the majority of your gas and have lost that extra weight. At the safety stop, suit compression is less. You should be able to hold that depth with little to no air in your BC and then make a nice, controlled, slow ascent to the surface. Doesn't that make sense to you?

 

[Edward3c]

Really, that was not such a big issue. After that day, I did 4 dives. I systematically did a buoyancy check at the beginning of the dive but the result was not what was expected. My head was submerged with 6 kg and exhaling but I could not descend until I had 8. It’s not a big deal really. It is just that the pre-dive check seems to be not reliable. But doing the check after the dive does not seem logical to me either.

Last Saturday I took a 12Lt 232bar down to 45bar. I off loaded 2kg at 2.5m. Without the 2kg I was slightly buoyant. I’ve now taken 1kg off my weighting for that configuration.

 

[Dody]

[QUOTE="Dody, post: 9369112, member: 520741"...It is just that the pre-dive check seems to be not reliable. But doing the check after the dive does not seem logical to me either.

You should rethink that. At the end of the dive, you have used up the majority of your gas and have lost that extra weight. At the safety stop, suit compression is less. You should be able to hold that depth with little to no air in your BC and then make a nice, controlled, slow ascent to the surface. Doesn't that make sense to you?[/QUOTE]
Yes. What I meant is doing a check after the dive as opposed to before did not make sense. If I always have the same gear, it might only be useful for the next dive.