weight

[badgers]

maybe this is the wrong forum for this question but, how do you figure out how much weight to put in you BC?

Dive instructors have alway given me a weight to use but I don't know how they figured it out.

Do you put weight in the trim pockets first? it seems that it would make it more comfortabe to keep the weight off my mid section.

PS zeagle escape.

thank you for your time and have a good day

 

[JamesK]

Well, the easiest way to figure out how much weight you need is to deflate your bc and hold a normal breath. You should float at eye level. The water should be about halfway up your mask. If you go down further, you are overweighted, if you do not go down, add more weight.

I recommend putting in a little less than you think you will need. Then, if you need more, hold onto the weights until you find the right amount. Then you can add them to you weight belt or pockets.

 

[donacheson]

Originally posted by Big James
Well, the easiest way to figure out how much weight you need is to deflate your bc and hold a normal breath. You should float at eye level. The water should be about halfway up your mask. If you go down further, you are overweighted, if you do not go down, add more weight.

With a full tank or a near-empty tank? There's about a 5 pound difference in the case of an Al80.
With what kind of a wet or dry suit?

A much more accurate approach is to carry enough weight to be neutral at 10 or 15 feet with a near-empty tank, say one with 500 psi left in it.

Proper weighting can easily be determined in a pool. Put on all gear and a tank with about 500 psi in it, empty one's BC completely, and take weights of the edge of the pool until one sinks.
Alternatively, put on a weight belt with too much lead, sink to the bottom, and remove the weight belt while holding on to one end. The weight left on the bottom is unnecessary.

Add 2.5 to 3 percent of body weight for salt water.

This approach also works well in salt water if there's a shallow bottom available at the end of a dive.

One can easily make allowances for a partially full tank - just add 1 pound for each 500 psi over 500 psi if using an Al80.

 

[JamesK]

Very true.

I dive steel hp 100's though. I guess I never thought about AL, and just went with what I do.

 

[badgers]

bottom line is I need to get into the pool and test things out.

I always wondered how the dive instructors knew to give me X amount of weight.

I will need to try my rig out with different tanks to see.

I try to rent steel 100's but some times I get 80's

thank you for your time and have a good day

 

[sumguy]

I think this was just discussed on another thread, and it was debated whether it's best to be neutrally buoyant at fifteen feet (with a near-empty tank) or at the surface. The point was made that if you're neutral at fifteen feet, you'll be positive during the final part of your ascent, and the last fifteen feet is where you should be ascending the slowest.

As far as whether to load your trim pockets first, Rodale's (or maybe another publication) had a good article. Basically, it boiled down to experimenting. If you turn belly-up, move some weight to the front, etc. Everyone's different.

 

[scorpiofish]

I don't understand how you don't already know how to check for neutral buoyancy. Checking for neutral buoyancy is done during confined water and rechecked during every dive in open water.

It's also in your open water manual.

As far as tank buoyancy, it doesn't matter whether it's AL or steel. Air has weight. As you use the air in your tank, it becomes more buoyant. The amount of weight swing is determined by the total volume of air from beginning to end.

How you split your weight depends on how much total weight you carry plus your individual tastes and center of gravity. Start by putting all of it your normal weight pockets or weight belt. Check your trim. Move weight to trim pockets as needed. I carry little lead and none in the trim pockets. Too much in the trim pockets tends to make you roll too easily.

 

[badgers]

scorpiofish: I do know how once I am in the water

I was looking for the secret that the dive instructors know.
Ever dive instructor I have dove with told me how much weight I would need in the dive shop, not at the dive boat.

it is not practical to get on the dive boat with more lead then I need and with all the waves check for neutral while dropping lead on the reef

the neutral at 15' was not discussed in my OW course.
also:
rechecked during every dive in open water.
I do not sit next to the boat and ask for more lead on every dive untill I figure out I have enough. I put the estimated weight on and then go. I have never been on a boat where someone took 5 min while they rechecked their weight once in the water.

 

[donacheson]

Originally posted by badgers
scorpiofish: I do know how once I am in the water

I was looking for the secret that the dive instructors know.
Ever dive instructor I have dove with told me how much weight I would need in the dive shop, not at the dive boat.

it is not practical to get on the dive boat with more lead then I need and with all the waves check for neutral while dropping lead on the reef

the neutral at 15' was not discussed in my OW course.
also:
rechecked during every dive in open water.
I do not sit next to the boat and ask for more lead on every dive untill I figure out I have enough. I put the estimated weight on and then go. I have never been on a boat where someone took 5 min while they rechecked their weight once in the water.

Getting neutral at 15 feet at the end of a dive with an empty BC and near-empty tank wasn't discussed in my class, either. I found, however, that the technique discussed, enough weight to sink one to mid-mask at the beginning of a dive, left me under-weighted, especially in the tropics with no wet suit compression to keep me down at depth. Naturally, I then overweighted myself.

When I started decom diving on wrecks in North Carolina, it slowly dawned upon me that to minimize weights, I wanted to be neutral with an empty BC while doing my last (10 foot) hang. Of course, there was no bottom on which to place weights, but I found that I could empty my BC on the anchor line and feel whether or not I was heavy. If so, I'd remove a few pounds between dives and repeat the process on the next dive. It only took a few dives to get close to the minimum. Once known for a specific gear configuration, a note in the back of one's logbook is helpful.

I think the penalties for carrying too much weight are the increased difficulty with buoyancy control and holding a horizontal position, although the latter also depends upon weight distribution. Of course, there are good reasons to overweight; I once dived in Palau with a professional photographer who carried an extra 10 pounds so he could kneel or lie on the bottom in surge or current while waiting to get the photo he wanted. Interestingly enough, he carried much of his weight in special pockets sewn into the chest of his 1 or 2 mil suit. I have no idea how tech divers weight themselves.

 

[herman]

Bager,

I actually check my weight AFTER the dive on a lot of dives, at least once a trip, sometimes more if I have new equipment or in a new diving situation. If I am diving an unknown, I take my best guess based on similar dives from my logbook and maybe add a couple of pounds and go diving.I am almost always within a couple of pounds this way. I put some of the weights into my BC pockets and at the end of the dive while waiting for the rest of the divers to exit the water, I can check my bouyancy, removing weights from my pockets and handing them to my buddy as necessary. After figuring out the correct weight, it gets logged with all the details, water, wetsuit ,ect,ect. It does not take too many dives to build yourself a good guide for you. If nothing else, it gives me something to do while waiting for the ladder to clear.

As for the neutral at 15 ft, there seems to be 2 schools of thought on this. One says to be neutral at 15 ft and the other at the surface, both of which with about 500 psi remaining. I prefer the surface to be neutral at. If you are neutral at 15 ft with an empty BC, a low tank and any sort of wetsuit at all, you will be positive above 15 ft and the only way to stop an uncontrolled accent is finning. I don't like having a zone in which I have to fight to keep control.

I suspect the "secret" is just experience. After getting a lot of new divers geared up, it should not be too hard for an experienced instructor to make a educated guess at what a diver should need.