Weighting systems, trim and weight distribution ideas

[Storm]

Weighting systems....they got me curious.

First off, we're not getting into (I hope) an integrated vs. non integrated debate. Don’t care one way or the other to tell you the truth. Here's the question....

If you're trimming out using tank weights, how much of your overall weight can/should be shifted from your belt to the tank pouches.

I have heard that placing a third of your overall weight in the tank bags, with the remainder on your belt is not a bad combination, and is used by some who have weight integrated BCs but prefer not to have a single point of failure (dump) for all their weight.

Now that the question has been asked, let me explain.

Judy and I are moving toward soft weights (personal preference), and we have also been thinking of reducing the amount of weight we carry around our waists. The BCDs we have are not weight integrated, but do have dual tank straps, so there an opportunity to migrate some of the weight from our belts to the tank straps and potentially trim out a bit better.

For the purposes of this discussion, we're using full 7MM suits,, her weight requirements are about 20 LB total, and mine runs around 24 pounds total (Both are probably a bit high, but that where we are right now...we're hoping for some weight reduction in the future due to a new weight training plan and gaining more experience, etc.)

We were thinking of distributing our weight in the following manner.
Both - 8 LBS on the tank straps. (2 lbs per pouch per strap)
Judy - 12lbs on her weight belt
Rick - 16 lbs on my weight belt.

I know we have to hit the pool and test the trim to see if it works, but in the event that is does work I was if we would be breaking some safety rule with this configuration.

Please remember that we are fairly new divers, and are asking these questions, not to frustrate you more experienced divers, but to learn the best way to trim out and distribute our weighting.

Thanks in advance for you input.

 

[TSandM]

The two keys in weight distribution, as I understand it, are these:

1) In the event of a catastrophic failure of buoyancy (big rip in the BC bladder), could you swim your rig and any unditchable weight to the surface? You don't say what kind of tanks you are diving, and that makes a difference here. Eight pounds on the tank straps and 7 pounds negative from tanks, as my tanks are, is 15 pounds you have to swim up. You just need to know if you can do that. (BTW, this is based on losing your buoyancy compensator at max depth with max compression of your wetsuit.)

2) You want to move weight around until you trim out horizontally without effort. If 8 lbs on the tank straps does this, it's a good move -- as long as you can swim the rig up from depth if you have ditched what you can.

I actually dive 27 pounds total with a drysuit, and have five pounds in the backplate and 4 pounds on the tank bands. That leaves me with 18 ditchable pounds. At the very worst, with full tanks and total buoyancy failure (which means ripped wing AND flooded dry suit -- unlikely -- I'd be swimming up 16 pounds. I really ought to try and see if I can do that. I haven't, because I'm not very worried about losing both my wing and my dry suit on the same dive. But it's a risk.

 

[Xman]

I mostly agree with TSandM's post above.
I would investigate the option of a weight harness system also as these are great for people who require a fair bit of weight and are using thick wetsuits.
Trim so that you are comfortable horizontal and not needing to actively try and stay that way.
As far as ditchable weight, it depends on what you want to achieve.
In my opinion, with the distribution you described and the amount of weight you have overall, I would not see that as being a safety issue as far as being able to ditch enough weight.

You should be able to swim your rig up from your maximum depth WITHOUT ditching your weights in the event of a bc bladder failure. If you cannot then you might want to consider a different combination of cylinder/s and exposure protection.
the reason for having ditchable weight is really for at the surface.
From the way your question was asked I am assuming that you are not yet talking about a doubles rig or any overhead environments.

 

[Vayu]

Yeah.. you need to be able to swim that junk up. In my OW class we had to swim a 10 lb brick up with no fins. Stick your fins on, add all your weight up, start swimming and treading.

The inverse of this is that you need to be able to control your buoyancy should a catastrophic failure of your weightbelt occur. How much will flaring out or swimming down prevent your ascent? Which do you think is more likely: A bc/drysuit failure or a weight belt buckle coming unbuckled?

I was on a boat with a guy who lost all his weight at 60' and corked.

Consider these two extremes and you will likely find a starting point for weight requirement and distributions.

-V

 

[bradshsi]

You didn't mention what cylinder type you plan to use.

This makes a difference because as has been pointed out, you need to be able to swim up from depth having ditched weight. With the 7mm wetsuits, the compression at depth (and the consequent loss of buoyancy), needs to be considered. If you have a steel tank that is negatively buoyant, you will need more ditchable weight than if you are using an AL80.

For a weight carrying system I like and use the DUI Weight and Trim II. This has 2 advantages over traditional weight belts.

1. It is much more comfortable for those of us carrying 20 - 30 lbs of weight.

2. You can ditch half of the weight at a time, whcih is useful if you are nearer the surface and you have more wetsuit buoyancy.

 

[Darnold9999]

Re swim all the weight and your rig up from depth.

Don't think that applies up here. 30 # of lead, 6 # backplate plus tank at -5 # boyancy is a lot of weight to swim up. Don't know if I could do it, I doubt it. Partly why I wear the harness. I can ditch in parts if required and no buckle to fail and lose the whole belt.

 

[scubajcf]

This might be an option.

http://www.dui-online.com/bc_wt.htm

 

[Storm]

Thanks for the input guy, I did forget to mention the follow and for that apologize.

MY wife and I are diving AL80s (single tank configuration), and all of our weights are soft weights in pouches (even the one on the tanks straps) so baring a combined bladder failure, and OOA we should be able to, as a team (and we only dive as a team) to ditch the tank weights by opening up the pouches and dropping the weight.

Our weight belts are pouch belts so we can drop a portion of the belt if necessary.


So with this is 1/3 on the tanks and 2/3 on the belt a safe configuarion?

 

[jeckyll]

Storm: When I was going through and deciding what to purchase for weight, I had some longer discussion with the folks at my LDS and came up with a min. ditchable weight amount of around 16 lbs, with 18 lbs distributed between SS backplate, p-weight and pouches (I'm 195). I was thinking of getting a P-weight for my BP/W and some pouches. However, I'm diving dry so I was always looking to have extra buoyancy there.

In the end though, I went with the DUI harness (like in above post). It is significantly more comfortable than the softweight belt I was wearing before for wearing the identical amount of weight.

Just my $0.02.

 

[Storm]

The belts we are using are our own design, similar to the DUI, but with modificatons specific to our needs.

This is the one advantage to having a wife who dives and is also an accomplished seamstress.