Question regarding the way PADI teach how to weight oneself properly

Hi, I am terribly sorry in advance if this is a silly question, but I just can't wrap my head around it.

According to my PADI book, properly weighted means: " When weighted properly and holding a normal breath, you should float at eye level. " . That's it. They don't talk about adding more weight afterward to compensate for consumed air, etc.

Right, so say I'm diving wearing just a rashguard and short, in the tropics, with an AL80, an ALU backplate and that as a human being I'm born neutral. So I go in the water, with my weights and all, and I take my 'normal breath', hold it, and I float at eye level. So I'm theoretically all good. But now I want to dive. So I exhale, exhale, I'm 2 meters down and I have nothing left to exhale (ex smoker here ), so it's uncomfortable, so I breath in, and at that point surely I at best become neutral, at worst come back up because I inhaled 'too much'.

What I don't get, is that my BCD is empty, I'm not wearing a wetsuit, so there's nothing to compress and reduce buoyancy apart from controlling my breathing.

Surely it should say 'take a FULL breath', make sure you're eye level, THEN add 2kg to compensate for lost air. But then in that case surely in order to float at surface I'll need to inflate my BCD. Which renders the point about the breath moot.

Grrr I'm so confused

Well... two things... 1- When you weight yourself, according to PADI, you should have approx. 500psi in your tank, not a full (3000psi) tank (you'll have to do the PSI to BAR conversion). When you actually splash at the beginning of your dive, you'll ostensibly have a full tank, so you won't be neutral, you'll be considerably negative depending on the buoyancy characteristics of the tank. 2- A "normal" breath is, for all intents and purposes, a 'full' normal breath.

Dive safe...

P.S. Not a silly question... Welcome to the board...

You are close, either eye level with a full breath- lungs at max comfortable inflation OR eye level with 1/2 a breath and then add 2kg (assuming you are starting with a full tank) to compensate for gas use.

You weight yourself according to the gear you will actually be using for the dive. If a rash guard - rash guard; if a wetsuit - a wetsuit. You don't weight check in a rash guard and then go put on a wetsuit for the dive.

Weighting can become something of a fine art that takes either a patient mentor/instructor or time to develop. Most OW courses overweight divers a.) because they are rushing through the course material and want to charge you for a latter PPB course fee) and b.) want to make sure a new diver with poor bouyancy control can hold a safety stop. With better bouyancy control you will be able to dial in your weight to within a pound or two of neutrality.

For the life of me, I cannot figure out why people make this so difficult. It's brain-dead easy.

1) Put on enough weight such that you're descending without having to fin down.
2) At the very end of your dive when you're at 500-700PSI and at 15 feet, hand a 2 pound weight to your buddy or the DM.
3) Vent enough air out of your BC to compensate.
4) Still hovering at 15 feet? Repeat steps 2 and 3 until you can't hold depth with no air in your BC.

Done.

Moral of the story : If you don't need the weight at 500lbs and 15 feet, you don't need it at all.

Oh, last step: Make a chart on the first page of your logbook that covers the current gear config (Aluminum or Steel tank), Wetsuit, BCD if you have more than one, fins if you have more than one set, salt water or fresh, etc. Write down the weight needed for that config. Lather, Rinse and Repeat for your additional configs as you get to them.

Now you're all set. As soon as you get to the dive shop, you only need to refer to your chart to know exactly how much weight you need.

-Charles

charlesml3:

For the life of me, I cannot figure out why people make this so difficult. It's brain-dead easy.

1) Put on enough weight such that you're descending without having to fin down.
2) At the very end of your dive when you're at 500-700PSI and at 15 feet, hand a 2 pound weight to your buddy or the DM.
3) Vent enough air out of your BC to compensate.
4) Still hovering at 15 feet? Repeat steps 2 and 3 until you can't hold depth with no air in your BC.

Done.

Click to expand...

Although I agree with you that it is not rocket science, I see one potential problem with Step #1 of this method. Presuming we are talking about beginner divers trying to figure this all out (and the OP has 0-24 dives), I could see some divers way overweighting in Step 1. I say that because oftentimes beginners have a problem descending (and thus will think that, say, double the necessary weight is "right" in order to descend). (I know if I had used this when I was first starting out, I would have had 20# on. Well... I DID, actually.)

I wish I had been instructed in a proper weight check in my first OW dives. Proper meaning getting the basic weight from just floating on the surface and not from trying to descend. I'm sure it was in the book, but we were not shown that and did not do a proper weight check in class at all. I later read more on SB and did one myself by renting a tank for a day and going to a shore area where I could just get in the water and float, with weights I could grab from shore. After that I knew I was in the ballpark and if I was not sinking at the beginning of a dive it was something I was doing or not doing (yep). That made a huge difference in the success of my diving. I was rather overweighted before then.

I could see dives/climates for which the overweighting I suspect would result from beginners doing step #1 being somewhat dangerous, or at least sub-optimal. So I would say it's better to do a "proper" weight check at the beginning, (floating at eye level with normal breath and adding for gas to be consumed), and then possibly fine tune it later via the "check it more closely at 500 psi" method.

Blue Sparkle

With my method you won't be overweighted for more that ONE dive.

You have to start somewhere. It may be from an overweighted situation. If you're light at the surface, get another 2 pounds from the boat captain or whoever is still on the boat.

This nonsense of sitting on the surface and trying to decide if your eyes are above or below the surface if you have a full breath or not.... Jeez, you have to be kidding me. Take a stab at their weight and get the new diver down where they can have some fun.

At the end of the dive, pull some weight off at 500psi at 15 feet. That's where it really counts anyway.

-Charles

Take a deep breath and relax... it's only a weight check.

The potential problem with doing a weight check at the end of the dive is how are the weight attached during the dive. If they are on a belt they will be hard for a novice to remove one at a time. If they are in a weight integrated pocket the novice may risk dumping them all by mistake (depends on the pocket design). If they are loaded all loose somehow the novice must still be able to effectively dump them easily during the dive. The devil is in the details.

I don't have a problem with this method but it does represent issues for someone who is new to most aspects of the sport.

You can also do a surface check with a full tank by achieving neutrality and then adding enough weight to compensate for the air in the tank. For an Al80 this will be about 4-5lb's. Put a couple of 1 lb bullet weights somewhere safe on you and at the end of the dive remove these till you achieve the desired result.

I wrote a blog article that describes the different methods for precisely confirming your weighting:

Scuba Buoyancy Masterclass 4of9 - Assessing Your Weight Requirements

The PADI Basic Weighting Guidelines and Pre-Dive Weight Check are a simple methods of estimation and confirmation. Not the most accurate, but an effective tool to confirm the general effectiveness of your weighting before descent. Good if you're using unfamiliar rental equipment on a regular basis.

If you want to get your weighting established precisely, when using your own equipment, it's worth the effort to do a full shallow water weight check. Too few instructors teach this IMHO.