New Diver, Weight Questions...

[el_guapo]

Hola,

Just completed my OW in Monterey.

On my dives, I wore a 7mm jacket/john combo with 34 lbs of lead. I am buying gear now, and at one of the local shops, the gentleman behind the counter said that I was probably over-weighted.

I am 6', 185 lbs. He told me I should be diving with around 20 lbs, but I did have a pretty tough time getting below the surface as I was. Once I was under (about 10-15' down) I was fine, and even a little surprised at how well I could control my buoyancy.

Should I buy less weight than the instructors fit me with? I know there will be trial-and-error involved in this until I get myself trimmed out, but just looking for input.

Second question:
He also mentioned that in addition to having weight in the integrated pockets of my BC, that I should distribute some on a weight belt. Sounds rational to get some of that weight off my upper back, but what do you, the reader, think? And if you agree, how much do you think I should move to the belt?

Thanks,
Chris

 

[The Kraken]

Chris,

Take the opportunity on a dive in the near future to develop your proper weighting profile.

Weighting, like a major battle, is planned in reverse.

With a good dive buddy, your dive weights in as small increments as you can arrange, a bag or something into which you can place unnecessary weight, and just a teeny bit heavy at the beginning of your dive . . . end your dive with about 500 psi. At your 20-15' safety stop, empty your BC/wing bladder completely. If you start ascending, while taking normal breaths, add a pound or two until such time you can maintain neutral buoyancy. If you see that you're heavy, remove weight just a little bit at a time until you can maintain neutral buoyancy through your breathing. It's generally considered to be a good thing if you just so sliiiiiiiiiiiightly heavy.;

The weight you dive is predicated upon the amount of weight required to keep you neutrally, or very slightly negatively buoyant, AT THE END OF YOUR DIVE AT YOUR SAFETY STOP.

As you progress in your diving, that end of dive weight requirement will, more than likely, shift to the lighter side. But at this point, that is how you should weight yourself for a SPECIFIC RIG.

You will be your most buoyant at the end of your dive. Why? Because you've depleted the gas in your tank and it becomes more positively buoyant.

I tend to stay away from categoric statements such as, "You were overweighted!" because I am not personally familiar with your personal physical configuration.

Just suffice it to say that, if you can maintain neutral buoyancy and the end of your dive with about 500 psi in your tank, and an empty B/C or wing bladder, then you are correctly weighted.

the K

 

[ToPpS]

From my personal experience. When i was training (OW & AOW) we all started on 4 weights each. Throughout the open water dives we did a buoyancy check before climbing aboard the boat at the end of each dive. Each time i was told to take a weight off, until i was only left with 2 weights on my belt.

Having bought my own gear now the buoyancy of the new equipment doesn't match that of the equipment that I trained in. When i did my first dive in the new kit I still assumed that 2 weights would be sufficient.... I was wrong! It would seem that i need to go back to 4 weights and maybe wean myself off of the additional weights as i get used to the new kit.

So to cover your questions... i would say that being slightly overweighted is arguably better than being under-weighted. Purely because you can counteract the weight with a few presses of your inflation button. If you instructors gave you 32lbs then maybe that is a good place to start?

In terms of your new kit.... maybe an option is to buy everything you want and hang back on the weights of the moment. Borrow some weights for the dive operator and see how much lead you need for the new kit.

The idea of "spreading" the weight all over your body.... i'm personally not a big believer of it. And having weights on a belt and integrated into the BCD doesn't make much sense in terms of spreading the weight. I mean it's still all around your midriff! Some divers go as far as to place weights around their ankles as well....

In the end it's up to what you feel comfortable with. If 32lbs works for you then great!

 

[TMet]

The way I get my weighting in a new rig is pretty simple. Go to a pool with water up to your shoulders. Put on your wetsuit, booties, and any other exposure protection you use. Then grab a bag and add weight until you can just sink with empty lungs. (This is the part that messed me up when I started, I did weight checks while holding my breath with full lungs, this will overweight you) This will give you the buoyancy of your exposure protection. From there you just have to add/subtract weight to compensate for an empty tank. e.g. +4.4lbs for a Luxfer AL80 or -2.5 for a PST E780. This will give you a pretty good baseline to start with. You may end up adding a couple more lbs if your BC is really buoyant. I suppose you could do it with an empty BC without a tank as well, but I haven't tried it.

Here is a site with tank specs for most tanks you will find.
Scuba Cylinder Specification Chart from Huron Scuba, Ann Arbor Michigan

 

[The Kraken]

Yep, if you can get to a pool that's about 12 feet deep, that will be a great help.

the K

 

[rstofer]

As you will probably be diving at Monterey (cold water), you can consider (and choose to ignore) the following:

I'm 6'1" 210# and I have an AquaLung SolaFX 7/8mm one-piece wetsuit. With a 6# stainless steel backplate and a tank that is -2.5# at the end of the dive (HP 100), I need 20# of lead in a harness.

If I use a 2# stainless steel plate, I have to swim down the first few feet. So, maybe I am a couple of pounds overweighted.

I sink like a stone when the tank is full so I could potentially lose a few pounds. Tobin at Deep Sea Supply recommends a different initial weighting. Full tank, empty wing, float eyeball level at the start of the dive. That means, with an HP 100, you will be 8# light at the end of the dive, at the surface. It also means you have to swim down (or jump up and bounce down) the first few feet. Holding your safety stop and not having a runaway ascent is based on the idea that the neoprene compresses and doesn't uncompress for quite a long time after the dive. I haven't tried this approach yet, but I will.

Now, if I were to integrate my weights, my rig would weigh 43# (tank) + 6# (plate) + 20# (ballast) + 2# regulator or just over 70#. I can't (or don't want to) lift that much weight. I prefer my ballast in a DUI Weight & Trim Classic harness.

FWIW...

Richard

 

[GrumpyOldGuy]

The way I get my weighting in a new rig is pretty simple. Go to a pool with water up to your shoulders. Put on your wetsuit, booties, and any other exposure protection you use. Then grab a bag and add weight until you can just sink with empty lungs. (This is the part that messed me up when I started, I did weight checks while holding my breath with full lungs, this will overweight you) This will give you the buoyancy of your exposure protection. From there you just have to add/subtract weight to compensate for an empty tank. e.g. +4.4lbs for a Luxfer AL80 or -2.5 for a PST E780. This will give you a pretty good baseline to start with. You may end up adding a couple more lbs if your BC is really buoyant. I suppose you could do it with an empty BC without a tank as well, but I haven't tried it.

Here is a site with tank specs for most tanks you will find.
Scuba Cylinder Specification Chart from Huron Scuba, Ann Arbor Michigan

Adding extra weight for tank bouyancy is not necessary when you are wearing 7MM FJ+J. The compression of the suit at 15' may completely compensate for empty tank bouyancy. When wearing this much neoprene, there is simply no subsitute for checking your weight at the end of your dive and adjusting unless you desire to dive overweight. Been there, done that, lost 6lbs of lead.

 

[spectrum]

el_guapo

Your weight of 34 pounds in salt water may have been OK for you now in the gear you were diving at the time. Nobody here can say. 34 pounds with an AL80 and a nice buoyant suit is within the realm of possibility. In addition to the gear most new divers keep their lungs on the full side and that adds to the weight requirement by a few pounds.

What you need to do is get into whatever gear you plan to dive, be it rental gear for now or a whole set of new stuff you buy and do a weight check.

You mention noticing your buoyancy changes with depth. That's good, you're paying attention. Remember that neoprene will compress and change buoyancy with depth. Also as you deplete the air in your cylinder you will gain buoyancy. The point here is that there is no such thing as a constantly perfect weight to carry. That is why you have a buoyancy compensator, to add lift when you are too heavy.

So the next question becomes, when do I need the most lead? The answer is at the end of your dive as you approach the surface. By then your cylinder is light and your neoprene is rebounding. You never want to be in a situation where you helplessly float to the surface. Here is a technique for arriving at that weight.....

Remember to set your weight so that you bob vertically at eye level at the end of your dive with an empty BC, an average breath, your feet still (crossed) and about 500 PSI in your cylinder. A deep breath should get your mask out of the water and a deep exhale should sink your mask. Do all of this while breathing from your regulator. The end of the dive is the defining moment for your weight requirement and you want just enough to let you stay down in the shallows with a light cylinder.

You can make the same test pre-dive with a full cylinder and add 5 pounds to compensate for the buoyancy gain you will experience as you breathe the tank down. Be sure to repeat at the end since you are apt to have some stowaway buoyancy (trapped air) in your gear early in the dive. You are safer being two pounds heavy than 2 pounds light.

You need to repeat this with changes in gear and as your gear ages and your comfort increases. With experience you will be able to make judgments just from how things feel at the end of your dives as you surface with a light tank. Slowly you may drop 4-6 or even more pounds of weight as you gian experience.

Now to question 2.

Between how much to wear and where to put it we must realize the concept of trim. Trim means having your weight distributed so you naturally dive in a prone form. Not foot heavy, not foot light. Trim may be influenced by a number of factors. Some things like your suit and fins we will accept for what they are.

The major "knobs you can turn" include how high you wear your cylinder and where you put your lead. Some may be on a belt, your BC may include ditchable hip pockets and you may had some fixed pockets up near your shoulder blades. There are other options you probably don't need to consider like ankle weights and strapping weights elsewhere.

In my opinion all of your weight except any you need to carry higher for trim should be on your belt. If you ever need to remove your BC underwater you will be glad to be one with your weight. If your hips do not provide a secure perch for a belt get a weight harness. The other advantage is that with a lot of weight in the BC it's a bear to handle, especially if you need to hand it up to a boat or otherwise handle it all decked out.

When buying weight be sure to include some pairs of lesser amounts so you can wean weight away as able.

Pete

 

[TMet]

Adding extra weight for tank bouyancy is not necessary when you are wearing 7MM FJ+J. The compression of the suit at 15' may completely compensate for empty tank bouyancy. When wearing this much neoprene, there is simply no subsitute for checking your weight at the end of your dive and adjusting unless you desire to dive overweight. Been there, done that, lost 6lbs of lead.

I agree with you. My advice is more to get a good starting point that can be tweaked on following dives.

 

[diver 85]

Sounds like for now you'll need 34--everything staying equal...Over time it'll(probably) get less, could get alot less maybe......Remember this, you can always sell or give away the extra weight you end up with......

On the 2nd part, my 1st almost thousand dives I wore 100% wt belt........since I changed BCs(with wt pockets on the rear) I generally go with about 50-50 now.....