How to shed those kilos?

[Jim Kerr]

I beg to differ. It is NOT transferring weight. A steel HP tank is at least 2 lbs negative when empty, while an aluminum tank is often 2 lbs positive when empty. Subtract the two, and you will SHED about 3 to 4 lbs from your weight belt.

Everything else is the SAME. Same suit, fins, BC, and mask. Only difference - you just shed 3 to 4 lbs off your weight belt.

Look it up yourself, Jim, Scuba Cylinder Specification Chart from Huron Scuba, Ann Arbor Michigan

Yes I know what you're saying but I believe he's trying to get his weighting down so that he's not over weighted. He can still be over weighted diving with a steel tank. So whatever he's diving with he needs to find his right weight and then he will easily be able to adjust to what ever tank size or type he's going to be diving with. I know that with my configuration it's only a matter of +/- 4lbs diving with AL or Steel..

 

[fisherdvm]

Simple math, going from a Luxfur 80AL to a PST 80 HP:

Weight empty 31.38 - 28 = 3.38 lbs
Buoyancy empty + 4.4 - (-2.5) = 6.9 lbs.

Total weight shed 6.9 lbs + 3.38 lbs = 10.28 lbs. 4 lbs by using a lighter tank, and 7 lbs off your weight belt.

10 lbs off your back and knee! That is alot more than 4 lbs you just mentioned.....

Heck, if you dove double with AL tanks, you will be lighter than helium.... Just kidding.

 

[hvulin]

stop waiving your arms and legs and breath out... (tie your legs together - one around the other, to be sure you're not fining)

relax and you'll be able to dive (make a safety stop) with a 1-2kg less

 

[TSandM]

Depending how your inflator hose is secured near your shoulder, you should be almost vertical, or slightly tilted backward to empty that last few cc of air out.

Really, this isn't true! I don't have to be vertical to empty my wing; I don't even have to come very much out of trim to do it. If a diver has to be vertical to empty his BC, it's a very poorly designed BC.

There are two places where a new diver finds himself needing weight. One is to descend at the beginning of the dive. This is one of the places were people end up overweighted, because their technique for descending isn't good. I had a lot of problems with this in the beginning. Many people, when they begin to descend, are unconsciously finning, and the finning drives them back upward. This leads to the perception that they aren't carrying enough weight. Crossing your ankles as you vent your BC can help stop you from doing this. Another thing is that, if you vent your BC and exhale at the same time, by the time your head gets underwater you generally need to INHALE, which brings you back up. A better strategy is to INHALE as you vent your BC, and as your head goes underwater, sharply and fully EXHALE, and it will continue to drive you downward.

If the problem that makes you feel as though you need that much weight is holding a stop at the end of the dive, it may be an issue of adequate venting. One of the things about ascending (or descending, for that matter) is that you have some momentum to deal with. If you don't begin to vent your BC until you're AT the depth where you want to stop, you can't stop there. As my Fundies instructor chanted to us, "Anticipate, anticipate, anticipate!" When you begin to move up, start venting right away, in very small amounts and frequently. Stay close to neutral. Jonnythan on this board gave me the advice to take a deep breath and start to move up; exhale, and see if I stop, and if I didn't, to vent. It worked very well. Staying close to neutral means it's always easy to change your momentum when it's needed.

And, of course, the final thing is that we need the weight we need, and there are no prizes for the person who needs the least. I am intrinsically very buoyant, and I've had instructors who have been floored at the amount of weight it actually TAKES to weight me properly. Doing a good weight check in shallow water is the best way to be sure you have the amount you need and not a lot more. Frankly, I'd rather dive a couple of pounds overweighted than too light; a couple of pounds doesn't make that much difference in the effort it takes to swim, or in my streamlining, but it makes me warmer in my drysuit and ensures I don't spend the last part of a dive uncomfortably swimming downward to avoid a too-rapid ascent.

 

[fisherdvm]

Really, this isn't true! I don't have to be vertical to empty my wing; I don't even have to come very much out of trim to do it. If a diver has to be vertical to empty his BC, it's a very poorly designed BC.

Might be due to design. But I see it all too often in the 3 OW courses I have assisted, and in my earlier dives. What I see is as followed:

1. Inexpensive BC's with no butt dump, with only the inflator hose base pull dump.

2. Larger BC than the indidual size, resulting in adjustment strap pulling the attachment site of the hose low in front of the left chest.

3. Poor design of BC inflator hose attachment, mounted low in front of the left chest.

4. Few BC's made today having an independent right shoulder dump with its own dump string.

These 4 factors, combined with the PADI standard that you descend feet first and ascend in the "superman" headfirst position - result in total uselessness of the butt dump. I read the same advise even in the deep dive specialty book. Whereas, Lynn, you probably descend and ascend horizontally, and well versed in using your inflator dump and butt dump, right? I see this "superman" position as being silly. It might be fine for the last 10 ft, but the student is so ingrained with having both arms above their head, they forget that the most important skill in the ascent is watching your ascent rate... Can't be done unless you have your timer/depth gauge where you can look at. And all I see is that their SPG is dangling below their waist.

When the student try to dump his/her air, there is an U shaped kink in the BC inflator hose, trapping air inside the hose. While this amount of air is small, it is even worse when in the less than vertical position, because now the student can't elevate the tip of the inflator hose above the highest point in the BC, resulting in even more air trapped in the BC.

The only way that the studen't can dump the remaining air is by pulling on his/her BC inflator hose.

Butttt...... the instructor tells them not to do that, as it will harm their BC. So, you wonder why students are overweighted? They simply can't dump the air out of their BC!! It is funny, I keep on telling a student yesterday that he needs to ascend slowly. He keeps on being the first to surface. Why? He can't dump his air from his BC, and the bubble pulls him straight up.

So, the solution? Tell the student to use his BC inflator pull dump? The instructor kept on telling the student - use it only in emergency. So they don't use the BC pull dump. I can see their dilemma. Can't use the BC inflator hose activated pull dump, but the BC really isn't designed for any other way, unless they ascend and descend horizontally, making it easier to get the tip of the inflator hose above the BC; and also in this position you can also use your butt dump.

Hopefully someone can tell me how to use these restrictive devices better? If you watch the students... hardly any of them use their butt dumps at all...

 

[fisherdvm]

So, my advice to the OP?

If you find that you are floating upward at the safety stop?? Learn how to get rid of the last bit of air in your BC when you do your ascent - and use your leg and fins alot more to get to your safety stop while ascending quite negatively buoyant. At least at first... Until you learn how to use your BC better, and can dump air more efficiently for the last 15 ft. Then you don't need as much weight to maintain a safety stop with 500 psi. And again, keep still, like other have said, if you are perfected weighted and neutral at 15 ft.... But if you are not perfectly weighted, use your feet to maintain the safety stop, until you figure the buoyancy thing out better. Remember to make sure you dump more air out when you ascend the last 15 ft, if you are neutral at safety stop with some air in your BC. But the ability to be neutral at 15 ft might come later, early on, just use your feet to keep at 15 ft. It is safer to ascend the last 15 ft finning hard and ascending slowly, if you don't know how to dump that last bit of air out well.

If you find that you're floating upward when underwater at the bottom, be aware of all of your air dumping ability (where the butt dump is, where the shoulder dump is, if there is one), be aware of where the air bubble is. Reach back, and touch your BC, to feel where the bubble is at different position. Learn how to elevate the inflator hose just above your BC when horizontal - you can dump air this way, even when not in the superman position. If all fail... It is OK to pull on the inflator hose to get rid of that last bubble... So what if your BC fail in 4 years instead of 10? And you really don't have to tug on the hose hard, just slightly, and it will release air.

If you find yourself with difficulty diving under the water at the beginning of the dive? If someone assisted you to find perfect weighting with a just dove wetsuit and gear, and an empty tank from a previous dive... You are correctly weighted, and should be able to enter the water and dive. AS YOU ARE NOW TRULY 6 lbs NEGATIVE with a full 80 cu ft tank. The next time you dive with the same gear, you WILL find it difficult to descend, unless you did a pike dive, a deadman or spread eagle dive, and kick hard, all the while exhaling, to break the surface and do your descend. Even with the extra 6lbs of weight from a full 80 cu ft tank, you might have 8 lbs worth of positive bouancy from the air trapped in your suit, BC padding, and a fully expanded neoprene wetsuit. It is completely different than when you are in your OW class 10 lbs over weighted, and sinking like a rock at the surface.

 

[Jim Kerr]

Simple math, going from a Luxfur 80AL to a PST 80 HP:

Weight empty 31.38 - 28 = 3.38 lbs
Buoyancy empty + 4.4 - (-2.5) = 6.9 lbs.

Total weight shed 6.9 lbs + 3.38 lbs = 10.28 lbs. 4 lbs by using a lighter tank, and 7 lbs off your weight belt.

10 lbs off your back and knee! That is alot more than 4 lbs you just mentioned.....

Heck, if you dove double with AL tanks, you will be lighter than helium.... Just kidding.

Well, I only have to add 4 lbs to my weight belt when diving with Al 80s to what ever I use with Steel 80s, and I am not over weighted with either.

 

[Rosbif71]

I dive in the Indian Ocean (water temp 25 deg C at the moment) with 26lbs and no suit.
I'd rather be a little over weighted than have trouble making my safety stop.

 

[fisherdvm]

Well, I only have to add 4 lbs to my weight belt when diving with Al 80s to what ever I use with Steel 80s, and I am not over weighted with either.

I just wanted to point out that there is an objective way to determine these numbers rather than just guessing and eyeballing. You might have different tanks thatn a Luxfer and a PST HP.

 

[Diver Dennis]

I dive in the Indian Ocean (water temp 25 deg C at the moment) with 26lbs and no suit.
I'd rather be a little over weighted than have trouble making my safety stop.

Wow...