How Much weight???

[flots am]

How much weights should you have? in relation to your weight?

I weight around 170 lbs. wearing a 0.5mm wetsuit. wearing jet fins (negatively bouyant)

Im using 10 lbs weight. Now dropping to 9.6 lbs. How far can I expect to loose?

is there a percentage?

Nobody can tell you. The only way to find out is to do an actual buoyancy check, for yourself, as described in your OW book.

You need just enough weight to sink you with a nearly empty tank and no air in your BC. Anything more is too much and anything less isn't enough.

flots.

 

[RonFrank]

I don't mind being a few lbs over weighted. It really does not impact me much.

I'd rather be over weighted that under weighted.

But most think over weighted is like devil worship or something.... I just don't think a lbs or two matters much.

 

[ajtoady]

As you probably have gathered it depends on the individual and his outfit or gear. Me personally in a 3/2/2 with my Faber HP 117 use no weight and at the end of the dive still am negative with about 700psi. In my 5 mm farmer john I use about 9-10lbs and that will get lowered as the wetsuit ages. Best thing as stated is do a weight check at the end of your dive. By doing that you usually have all the voids filled and the air pockets out of your wetsuit and gear.

 

[Juardis]

Informative thread. As a yet to be certified diver (take the OW test this Sunday), I have a billion questions. But the one pertaining to this particular thread is this. When is it best to do a weight check when you go on a "real" dive?

Let me elaborate. In a pool with my 3/2 wetsuit and AL tank, I use 4 lbs, and that may still be too much. This past weekend we put hoodies on as well as a 7mm farmer john over my 3/2 suit and I still used 4 lbs and was still able to get to 15 feet (and stay there with 500 psi in my tank). A tad more difficult, but still possible for me. Had to exhale extra long and extra hard for a few breaths, but that seemed to do the trick. So anyway, in a pool, about 2-4 lbs seems right for me.

Now in 1 months time wife and I are going to St. Lucia (Sandals). This will be our first experience diving let alone in salt water. So as to not tick off the more experienced divers by us testing different weight amounts after jumping in the water, when is it best to do the weight check? I've read here where you can ask Sandals (or the boat operators) to take you on a check out dive where you do all that bouyancy checking. Is that possible? Would you recommend that? Or do the experienced divers understand when there's a newb that there might be a bit of a delay starting the dive as they try to get their weights correct? I already feel like we're going to hold everyone up regardless of when we do a weight check, just trying to be considerate and not such a clueless newb.

thanks

 

[flots am]

When is it best to do a weight check when you go on a "real" dive?

Any time you have access to the equipment, the water and some weights is a good time.

Now in 1 months time wife and I are going to St. Lucia (Sandals). This will be our first experience diving let alone in salt water. So as to not tick off the more experienced divers by us testing different weight amounts after jumping in the water, when is it best to do the weight check? I've read here where you can ask Sandals (or the boat operators) to take you on a check out dive where you do all that bouyancy checking. Is that possible?

Ask them when you get there. I'm pretty sure they'll be very happy to let you get your weighting figured out when they're not staring at a boat full of divers that want to get started. You don't need a boat for this, just access to water that's deeper than you are tall. A beach is just fine. And they don't even need to be there. You just need your buddy, your equipment and an assortment of weights.

Depending on your body composition and size, you'll probably come in somewhere between 12 and 22 pounds, so if you borrow an assortment of various sized weights that add up to about 22 Lbs, you should be able to mix and match to get the right amount.

Also, you don't need to actually empty the tank to do your test. A full 80 cubic foot tank contains just about 6 pounds (by weight) of air, so once you know what it takes to sink you with your tank, just add about 6 pounds, and you should be very close what you'll need when it's empty. You might find this weight goes down a little over the week as you relax.

Also, in general, don't worry about annoying other divers just because you're new. We were all new once, and everybody has done their share of dumb things and has annoyed their share of other divers, whether they admit it or not.

flots.

 

[Blue Sparkle]

A while back I was in a similar situation: I had new equipment (my own, finally!) and no way to do a weight check before I left home.

What I did was rent a tank/weights the day I arrived (not diving 'til the next day) and go to a nearby place where I could get into water that was over head deep. I guessed on weighting and put the rest of the weights where I could get to them (also my buddy was there so only one of us did the weight check at a time).

I had a full tank, so I did the usual "add weight until I float at eye level with a medium breath and an empty BC." Then I just added 6# to that (mentally) to get my total for diving. The 6# was because that is the weight of the air that is in an AL80. By adding the 6# I ensured that I wouldn't be too buoyant when my tank was low at the end of a dive and I needed to hold a safety stop.

The above was summer warm water dives with no exposure protection to account for.

I always make notes in my log about equipment/tank/weighting so that by now, unless something changes, I know just about what I need for various combinations of tanks, exposure protection, etc. Of course one can always make another weight check too.

There's nothing to say you can't do the weight check at the beginning of the dive either, although I could see where rough conditions, or a group-led type dive might make it less desirable. In my case I wanted all the time I might need for checking out my new gear, tweaking, etc.

(By the way, I don't mean to insult your intelligence because I'm sure you learned this in OW class; I'm just describing what I did when I went on a dive trip and wasn't sure about my weighting).

 

[boulderjohn]

I had a full tank, so I did the usual "add weight until I float at eye level with a medium breath and an empty BC." Then I just added 6# to that (mentally) to get my total for diving. The 6# was because that is the weight of the air that is in an AL80. By adding the 6# I ensured that I wouldn't be too buoyant when my tank was low at the end of a dive and I needed to hold a safety stop.

This is, indeed the recommended method, and it works pretty well. There is a little touch of controversy about it, though, because some people think it is not necessary to add the weight for the air, at least no the full 6 pounds. Their thinking is based on the belief that when you do the standard weight check such as you describe at the very beginning of a dive, there is a lot of trapped air in the BCD, the wet suit, etc. that will go away during the dive. Additionally, the wet suit compresses during the dive and will not totally come back to form until some time after the dive is over. The thinking, then, is that there is enough additional buoyancy in your system during the weight check to take care of the loss of the weight of the air in the tank.

Notice that I did not take ownership of that theory. That is because I don't know exactly where I stand on the issue and have no plans to do any kind of testing to find out.

That is because I usually have to dive overweighted, and I have gotten used to it. When I dive with a backplate and steel doubles, I have no choice. Even empty, they weigh more than the weight I need at the end of the dive. When I have dived with a BCD and 3mm suit in the ocean, I have learned that it is more important to me to have the weight properly distributed so that I can swim easily in proper trim during the dive. That means I am at the mercy of whatever sized weights are on the boat. I normally end up a couple of pounds over ideal. One time the boat had nothing but 4# weights, and I was pretty sure I needed 8# to be perfectly weighted. I needed to distribute that weight in four places if I wanted to have good trim, but that would mean I would have 16#, or double my needed weight. I did it that way and did not regret it.

 

[Blue Sparkle]

Good points, John. A couple of notes:

1) I was wearing no exposure protection at all - just a Lycra shirt and shorts - so there were not too many places for trapped air.

2) I did, after a few dives, reduce my weight by a pound or two. Of course I don't really know if that was "adding less per pound of air" or "me getting a bit better at diving and weighting."

3) Now that I have dived more in my various typical configurations, I have had chances to hold my stop (on a line, just in case) while breathing down air to 500psi. So now I go with just enough weight at that point to be able to comfortably hold the stop, plus a touch more, in case I did get below 500psi.

I find it fun to keep track of the various combinations of exposure protection, tanks, etc. and getting my weighting just right. To that end I carry four 1# weights of my own, because I have found - like you - that while dive boats usually have a great selection of larger weights, the 2-pounders go fast, and the 1-pounders are non-existent on many. I also spread the weights around, so one 4-pounder is not idea.

The one time I was really thrown for a loop was my first freshwater dive. Just to add to the "fun" it was a one-day class that had been changed at the last minute. I was supposed to have a day to dive on my own and get things sorted out and then the class the day after that. Instead the class was the first day. Not only did it take me some time to get sorted out, but I swear it never did feel as "steady" as salt water (I know salt water is more buoyant, but it just surprised me how it felt "different" as well). I hope to do some more fresh water diving

 

[Juardis]

Ask them when you get there. I'm pretty sure they'll be very happy to let you get your weighting figured out when they're not staring at a boat full of divers that want to get started. You don't need a boat for this, just access to water that's deeper than you are tall. A beach is just fine. And they don't even need to be there. You just need your buddy, your equipment and an assortment of weights.

Outstanding idea. Never would've thought to just walk out into the bay and test it. Thanks for that.

 

[fisheater]

When I test out my weighting with a new gear configuration, I make an educated guess as a starting point and do a shore dive. With a sandy bottom at 15 ft. I purge my tank down to about 500 psi and remove weights by placing them on the sand until I'm no longer neutral. I pick up enough weight to be neutral again and that's my future weighting for that configuration.


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