Weighting

[tombiowami]

Ok, let's say my primary concern is being able to swim my rig up from 120' with no help from the bc or wing inflation. It decides to go kaput. At that depth I am assuming that all buoyancy from my 5mm wetsuit has been crushed out. (in addition, can some one let me the corresponding depths and wetsuit loss of buoyancy? Just curious, it seems it would be the same as standard gas, like losing half at 33', etc. but I do not know.)

How much weight could a typical diver swim up, if there were no ditchable weight? I am 38 in good shape cardio and all. I know it would be different for different divers but just looking for ballpark figures or input. (I also carry a dive alert marker with 52 lbs lift as backup, but do not want to depend on that)

The issue driving my question is that I need about 9 lbs of weight with my 5mm suit to keep down at 300psi at 10'. If my bp weighs 6 lbs, I carry 4 of ditchable. I am considering a single tank adapter which would weigh 3 lbs, and I would carry no weight. I have not been very deep but will start this spring. I know one option is to get an aluminum bp, and carry the 6 lbs on my belt, but I don't want to get it if I do not need it.

Any help...

Tommy

 

[Lost Yooper]

What kind of tank are you using?

Mike

 

[100days-a-year]

Tommy,it doesn't have to be real complicated.I add my swing weights from wetsuit compression and air consumption ,subtract the b/p and stuff and wear that amount of weight ditchable.Ditching when wet is bad at depth unless you are about to die or are in serious danger.The added speed at about 60' or so as the suit starts to expand could(has for me)cause a rapid ascent.The balanced rig is a serious misnomer as at the begining of the dive you'll be pretty heavy.If we assume an al80 and 5lbs of wetsuit compression with 4 ditchable leaves you swimming up around 8lbs.With doubles or bigger tanks a "balanced rig" is more difficult as the air swing can be as great as 15lbs or so even with 1/3s.That is the reason wetsuits are less desirable at depth when diving doubles steel or not.Don't let anyone talk you into believing there's some sort of way to cheat physics,it's just easier to do the math.

 

[tombiowami]

Aluminum 80, I thought of that later after the posting and the significance due to the swing weight.


100 days- Thanks for the reply. I am not sure what you mean about cheating physics. I understand the wetsuit being not the best due to the compression aspect. I also understand the idea that dropping weights does not necessarily put you in a better position, as shooting to the surface you can entail bubbles fairly easily.

I am just trying to figure out if I could swim up 9 lbs. of weight plus a full alum80 of gas.

Which brings up another topic, anyone have stories of uncontrolled ascents due to weight belt dropping, either on purpose or not?


Tommy

 

[BadFish]

Well sort of, i did catch a guy once at 70'. I was just hitting the bottom at 70' at the anchor line when i saw a guy messing with his camera, this was his first day diving since his OW class and the third dive of the day, his wife (buddy) was cold so she sat this one out.

Anyways as i dropped down behind him i noticed that his weights were sliping down around his waist, so i swam towards him when BANG! they sliped, and i had just enough time to catch the weight belt with my left hand and his BC with my right. My buddy then grab the diver and help me put his belt back on. When we got him to the surface we talked to him about how much trouble he had been in and what could have happened to him.

I also explain that, that is why a buddy is so important. If My buddy and i had not been there.

Anyways.

 

[100days-a-year]

Tommy,I was referring to the difficulty invoved in swimming up the swing weight if the dive is aborted early(most dives are)With your situation I can do it but as the swing gets higher due to more air or wetsuit compression(even neoprene drysuits)it become difficult .In the technical arena where you may swing 15-20#s just in air it is little harder to call that rig balanced even tho at 1/3s you may be weighted properly.I dive an 80 to depth with an S/S b/p ,STA and am nuetral in skin,tank empty.With rubber on and up to 16 lbs I can swim it up no prob.

 

[tombiowami]

100 days, thanks, that is what I was looking for. I guess it also begs the question concerning dropping weight and its true value. By dropping a belt and rocketing to the surface you definitely put yourself at risk for dci and age in a big way. Even if someone finds you unconcious, and they drop your belt, they end up rocketing to the surface with you.

It really illuminates the fact that all dives are decompression dives as the ceiling would be the ascent rate.

In what instance would any of you all out there drop your or someone else's weights?

Tommy

 

[Liquid]

I belive, that giviven the data you showed, you should be able to lift yourself with you legs. Remember that when filling your lungs you get a positive bouyancy of about 10 lbs that helps you, and that after the first 20 feet it will get a lot easier.

As 100 days said- the reall problem is that usualy it happens not when you tanksempty, but before.

If you are going to do deep open water dives (rather than wrecks or caves) it is better to use aluminum tanks.

 

[Lost Yooper]

That's why we carry a lift bag and reel.

Ideally, you want to have just enough ditchable weight so you can swim up with full tanks. I really don't know how much weight that is as I don't even own a wetsuit. I think ditching a weight belt should be the absolute last option too, but should remain an option if wearing wetsuit. A good buddy will be able to get you up if your BC fails as well.

Mike