Getting Your Weighting Right For Proper Buoyancy

[The Chairman]

I teach this a lot. First, trying to assess your weighting at the end of your dive is putting the cart before the horse. Think about it.

I recommend doing your first weight titration in a pool. Empty your weight pockets, so you have no weight in your BC. In the deep end of the pool, breathing normally on your regulator, cross your legs and arms. Have your buddy guesstimate how far you're sticking out of the water. Add a pound (0.5kg) for every inch (25mm) the top of you're head is above the water. Re-assess and keep adding weight until the top of your head is just awash. Stop. Exhale. You should be descending. That's it. Stop futzing with it.

Add 4 or 5 pounds (2-3kg) for salt water. You should be fine.

Now, if you already have your weights figured out, remember that the more relaxed you are, the less weight you need. Try dropping 2 pounds every now and then. If you're floaty at your safety stop, add it back. Remember, your breathing affects your position in the water column considerably. It's all about where you pause your breathing cycle. Pause with a full breath and you'll be the floatiest you can be unless you take a superbreath. Pause on the exhale and you'll be the sinkiest you can be unless you do a superexhale.

CAVEAT: Never, ever hold your breath!!! That means don't occlude your epiglottis at any time while you're at depth. BOYLES law really stands for "Breathe Or Your Lungs Explode, Stupid"

 

[tursiops]

I teach this a lot. First, trying to assess your weighting at the end of your dive is putting the cart before the horse. Think about it.

I recommend doing your first weight titration in a pool. Empty your weight pockets, so you have no weight in your BC. In the deep end of the pool, breathing normally on your regulator, cross your legs and arms. Have your buddy guesstimate how far you're sticking out of the water. Add a pound (2kg) for every inch (25mm) the top of you're head is above the water. Re-assess and keep adding weight until the top of your head is just awash. Stop. Exhale. You should be descending. That's it. Stop futzing with it.

Add 4 or 5 pounds for salt water. You should be fine.

Now, if you already have your weights figured out, remember that the more relaxed you are, the less weight you need. Try dropping 2 pounds every now and then. If you're floaty at your safety stop, add it back. Remember, your breathing affects your position in the water column considerably. It's all about where you pause your breathing cycle. Pause with a full breath and you'll be the floatiest you can be unless you take a superbreath. Pause on the exhale and you'll be the sinkiest you can be unless you do a superexhale.

CAVEAT: Never, ever hold your breath!!! that means don't occlude your epiglottis at any time while you're at depth. BOYLES law really stands for "Breathe Or Your Lungs Explode, Stupid"

So you think a pound is 2kg?
And you don't care how much weight is in the air in the tank?
Seriously?

 

[The Chairman]

So you think a pound is 2kg?
And you don't care how much weight is in the air in the tank?
Seriously?

A pound is 0.453592 kilograms, so 2 is close enough for me. An inch is actually 25.4 mm, so 25 is also close enough for me. Each inch above water is probably a bit more than a pound, which is why you add and assess until the diver's head is awash (just under the surface). Too many variables to do it otherwise.

If your head is just awash with the surface of the water, not eye level which is about 4/5 inches higher, then you've compensated for your full tank. But, you've done this at the beginning of your dive before you get to the point where you wished you had compensated for it.

You can always over complicate a simple process, but I don't see any merit in that. I try to simplify complex processes within reason, often separating them into discrete actionable tasks.

Ya, srsly!

 

[miked]

Pete, with all due respect, your post is backwards regarding lbs. vs kg. A kg is~ 2.2 pounds, "2" is close, but in your post you state that 1 lb ~ 2 kg. it should be reversed, namely 1 kg~2 lbs.

 

[The Chairman]

Oops... sorry. I'm suffering from surface narcosis! Maybe I should start drinking coffee in the morning after all! I'll edit the post to reflect reality!

 

[Diamond Reef]

Great information. Simplify, simplify simplify. Twenty years ago we took the concept of determining proper weighting to a slightly different place. At the time, divers' general buoyancy performance especially in shallow water, nearing the end of the dive was akin to a human 'strike indicator' or for you non-fly fisherman a 'bobber'. I think the rule of thumb up here in the Northwest wearing 1/4" neoprene wetsuits in cold water, and depending on the gear we were wearing was take 10% of the weight of the diver and add 10-15 lbs, then perform the surface/top of head/half breath estimate and adjust over the next few dives. My take on this then however, was and remains today, that most divers are not well practiced in free hovering with a near empty cylinder. As a starving dive instructor, I decided that figuring out how to motivate students to perfect that skill would make them safer, in the long run more confident, and would insure we filled the next stage of training after basic certification. Killing multiple birds with one stone... You may have read about the Diamond Reef® System and Challenge Course on Facebook. Part of the system included offering students the Simulated Empty Tank™ weighting procedure.

The ultimate goal, performing a 3 minute safety stop using only a depth gauge was always tough to master with a near empty cylinder due to mis-weighting, ever changing breathing patterns, cold and varying stress levels. The SET™ Procedure is as simple as it gets yet it takes planning, and an assistant to make it happen. Since inexperienced divers need time to practice this stop, it's clear you don't want them bobbing around in the open water with an empty cylinder. So we first computed the buoyancy factors of the divers' cylinders and initially added a pound or two due to air getting trapped in the old style bc's... Still happens. We established a staging area called a SET™ Line in 20-30' of open water (with an oversized custom inner tube/flag). Next we took a few one gallon milk jugs (Tuning Containers™ TC) down to 15' and added sufficient air to each to neutralize (between 5-8 lb weights). So the deal is, we have the student drop down to 15' of water with a full cylinder to reduce all of our stress and liability issues, then we simply attached for example, a predetermined 6 lb TC to their pack. Voila; a simulated empty tank and ample time to practice the safety stop. We would remove weights from their pockets or add small weights back. All weights can be hooked via snap clips to the SET™ Line. Involved yes, but well worth it. Students always came out of the lesson (cold) with a heightened respect for what skills to master and why. Our continuing-ed classes were sought after as we added value to the simple specialty outlines and always well populated. This practice remains to be a win win not just for the student and instructor (or our DiveMarshalls™), but for the Dive Center and the industry as a whole.

 

[The Chairman]

The ultimate goal, performing a 3 minute safety stop

First, the ultimate goal should be to have a fun, uneventful and neutrally buoyant dive, including the safety stop.
Second, five minutes will make you less tired after the dive.

 

[tursiops]

Great information. Simplify, simplify simplify. Twenty years ago we took the concept of determining proper weighting to a slightly different place. At the time, divers' general buoyancy performance especially in shallow water, nearing the end of the dive was akin to a human 'strike indicator' or for you non-fly fisherman a 'bobber'. I think the rule of thumb up here in the Northwest wearing 1/4" neoprene wetsuits in cold water, and depending on the gear we were wearing was take 10% of the weight of the diver and add 10-15 lbs, then perform the surface/top of head/half breath estimate and adjust over the next few dives. My take on this then however, was and remains today, that most divers are not well practiced in free hovering with a near empty cylinder. As a starving dive instructor, I decided that figuring out how to motivate students to perfect that skill would make them safer, in the long run more confident, and would insure we filled the next stage of training after basic certification. Killing multiple birds with one stone... You may have read about the Diamond Reef® System and Challenge Course on Facebook. Part of the system included offering students the Simulated Empty Tank™ weighting procedure.

The ultimate goal, performing a 3 minute safety stop using only a depth gauge was always tough to master with a near empty cylinder due to mis-weighting, ever changing breathing patterns, cold and varying stress levels. The SET™ Procedure is as simple as it gets yet it takes planning, and an assistant to make it happen. Since inexperienced divers need time to practice this stop, it's clear you don't want them bobbing around in the open water with an empty cylinder. So we first computed the buoyancy factors of the divers' cylinders and initially added a pound or two due to air getting trapped in the old style bc's... Still happens. We established a staging area called a SET™ Line in 20-30' of open water (with an oversized custom inner tube/flag). Next we took a few one gallon milk jugs (Tuning Containers™ TC) down to 15' and added sufficient air to each to neutralize (between 5-8 lb weights). So the deal is, we have the student drop down to 15' of water with a full cylinder to reduce all of our stress and liability issues, then we simply attached for example, a predetermined 6 lb TC to their pack. Voila; a simulated empty tank and ample time to practice the safety stop. We would remove weights from their pockets or add small weights back. All weights can be hooked via snap clips to the SET™ Line. Involved yes, but well worth it. Students always came out of the lesson (cold) with a heightened respect for what skills to master and why. Our continuing-ed classes were sought after as we added value to the simple specialty outlines and always well populated. This practice remains to be a win win not just for the student and instructor (or our DiveMarshalls™), but for the Dive Center and the industry as a whole.

Wow! Hard to see how this fits "Simplify, simplify, simplify!"

 

[Diamond Reef]

You're right. Should have said; Simply attach a 5-8 lb buoyant milk jug to your buddy's cylinder, based upon its buoyancy characteristics at the end of the dive to see if he can successfully perform a 3 minute stop. Adjust weights and breathing accordingly. Mia Culpa.

 

[The Chairman]

I have to agree with Tursiops here: Yours ain't a "simple" approach.