Weight distribution and ditchability questions.

[danpass]

So I've ordered the Aeris EX Lite BCD and have been pondering the weight setup.

Based on my fin tip bouyancy tests in OW, with a completely deflated Mares jacket BCD, 3/2 shorty with arms and the typical dive shop single tank, I am completely neutrally bouyant with a 14lb weight belt. We ended up putting a 2lb hard weight on the cam band lol. (without the shorty I'm at 12lbs)

OW skills was a bit challenging as the slightest current would start moving me lol. I prefer a slight negative bouyancy in order to stay still on sand.


Now with this new BC I'm looking for input on setting up the weight.

It has a ditch pocket on each side and two trim pockets on the cam band.

So far I have considered 10lbs on the waist (5lbs each) and six pounds in the trim pockets (3lb each). This way I can ditch a fair amount of weight at the surface if necessary to either help myself or assist with the buddy.

But I'm now wondering about 6lbs in each hip pocket and 2lbs each for the trim pockets.


Ignoring any significant differences in BC for now, what do you think?

 

[BluewaterSail]

The way to determine how much needs to be ditchable is if you can swim up from depth with no gas in the BCD, with full tanks. If you can, then you do not need ditchable weights. If you have trouble doing that, then figure out how much weight you can easily swim up. Then you will know what needs to be ditchable.

Besides that, experiment with what arrangement will be most helpful to you in having good trim.

 

[Craig66]

Also remember that some dive shops use 63's for their training and do that will differ from the 80's you are likely to use.


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[boarderX47]

I have the Aeris EX 200, which is the model up from the lite. In mine, I have 2lbs in each tank band pocket for a total of 4lbs in the back and then I had 4lbs in each front weight pocket. Floating on the surface was easy and the BC did not push me forward thanks to the weight in the tank band pockets.

The idea for your set up, 6lbs on the back and 10lb on the front sounds fine to me. Best way to know is to get in the water and experiment!

 

[elan]

Actually you should never (may be only in some exceptional cases) need to stand firm on the sand so if you base your weighting on that You will be always overweight.
I had to sit on the pools floor in my DM class and that required 4 more lbs. Thats a lot of overweight. I hated it...
I usually put 6 lbs on the tank bands woth Al 80 it offsets the positive buoyancy at the end and removes that floatty feeling towards the end of the dive.

 

[TSandM]

I flinched when I read that you want to weight yourself sufficiently negative to be able to sit still on the sand. Why would you sit on the sand? Diving is a floating activity.

But to address the rest of your question: The idea of ditchable weight is to be able to render yourself positive. Ditching weights is most useful at the surface, if you have some kind of problem and can't inflate your BC. If you are properly weighted, you start the dive negative by the weight of the gas you intend to use out of your tank, which for most tanks is in the range of 5 to 6 lbs. So if you keep that much weight ditchable, you should be able to render yourself at least neutral (at the very beginning of the dive) or positive (after you've used up some gas).

At depth, you have the additional negativity from compression of your exposure protection, but if you're wearing a 3/2 shorty, that's almost negligible. And I have a hard time envisioning any scenario where one would want to ditch weights at depth, since it renders you unable to control the subsequent ascent.

As far as the distribution of weight goes, so long as you have the minimum you need ditchable, distribute the rest of it so that it makes floating in a horizontal position effortless.

 

[danpass]

I have the Aeris EX 200, which is the model up from the lite. In mine, I have 2lbs in each tank band pocket for a total of 4lbs in the back and then I had 4lbs in each front weight pocket. Floating on the surface was easy and the BC did not push me forward thanks to the weight in the tank band pockets.

The idea for your set up, 6lbs on the back and 10lb on the front sounds fine to me. Best way to know is to get in the water and experiment!

Good stuff. I'm trying to create a flexible setup using the least amount of extra weights lol. In case I go with a full wetsuit for example or a 1mm full suit, etc.
Basically trying to limit any necessary changes to just the trim weight locations.

---------- Post Merged at 01:42 PM ---------- Previous Post was at 01:00 PM ----------

I flinched when I read that you want to weight yourself sufficiently negative to be able to sit still on the sand. Why would you sit on the sand? Diving is a floating activity.
................

I've noticed the general trend of the board of endlessly moving from place to place, always on the run, basically taking work underwater with them.

But sitting still in one location tends to reveal a great amount of activity as you 'blend in' to the surroundings. 10min here then move over there for another 10 min, etc.

---------- Post Merged at 01:43 PM ---------- Previous Post was at 01:00 PM ----------

Actually you should never (may be only in some exceptional cases) need to stand firm on the sand so if you base your weighting on that You will be always overweight.
............

I never said anything about standing firm.

The goal is to simply lay on the sand enough to overcome the effects of a mild/moderate current.