Yet another weight calculation question

Please register or login

Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.

Benefits of registering include

  • Ability to post and comment on topics and discussions.
  • A Free photo gallery to share your dive photos with the world.
  • You can make this box go away

Joining is quick and easy. Log in or Register now!

Painter

Contributor
Messages
152
Reaction score
54
Location
Provincetown, MA
# of dives
100 - 199
My last saltwater dive I was wearing a full 3mm wetsuit, booties, AL80 tank and a bcd that weighs about 8.3 lbs. I am 6' 2" and weighed 205 lbs then. After diving with 14 lbs for a couple of days I dropped down to 12 and found that to be about perfect.

The various weight calculators that I have looked at say that my optimum weights are anywhere from 14 to 18 lbs so none of the calculators look especially reliable, though the one that gave a result of 14 lbs is closest.

I now weigh 195 lbs and will be using the same equipment on my next saltwater dives. Should I stay at 12 lbs or drop down to 10?
 
The calculators are just estimates to get you close. If you found 12 lbs to be perfect, start with 12. Maybe you can trim off the need for another 2 lbs over multiple dives and drop down to 10.
 
As @Aviyes mentioned, they are starting points and individual people will vary slightly from those ranges. Dive what you feel comfortable and works best for you. The one way to really be sure is when you are done with your safety stop and at the end of your dive, if you are not yet at 500 psi, make a little jacuzzi and purge your tank until you get to that point. While at 15 feet, if you are still neutrally buoyant at that point, it is perfect for you. If you are sinking, it is too much weight. If you are floating, it's not enough weight.
 
I'd just use the same weight and do a weight check on my next dive, and adjust accordingly. Being a few pounds overweighted is no big deal, what you don't want to do is be underweighted so you can't hold a 10' deco stop if you need one.

@outofofficebrb describes my weight check.

Although I am precise about finding my perfect weighting, after adjusting for trim I usually am a pound or two heavy which is no big deal. May weight heavier depending on on the dive plan.



Bob
 
All you need is this: Optimal Buoyancy Computer
You might need 5-10 minutes to familiarize yourself with it, but then you will get all your questions answered plus several extra things to consider (alternative configurations, emergency conditions, etc).
 
Just a reminder, body weight is generally applied to exposure suit size which affects buoyancy. Body composition is mainly water, except in extreme cases. So, as your equipment has remained the same, your weights will remain the same. As always, the only 100% way to determine exact weight is a 10’, near empty tank , stop.
 
There is a lot if possible variability in that 8.3 lb BCD weight.....it surely weighs less than that submerged.....
 
All you need is this: Optimal Buoyancy Computer
You might need 5-10 minutes to familiarize yourself with it, but then you will get all your questions answered plus several extra things to consider (alternative configurations, emergency conditions, etc).
Well, maybe I was using it wrong after reading the instructions, but Optimal Buoyancy Computer was off for me.
 
Well, maybe I was using it wrong after reading the instructions, but Optimal Buoyancy Computer was off for me.

The variability (inaccurate results) in that calculator are probably from entering information about your personal buoyancy and wet suit (or drysuit) buoyancy that is not precisely accurate. The rest of the calculations are reliable.

As @Bob DBF suggested above, the easiest way to find your perfect weight requirement is to do your next dive with 12 lbs, and at the end of the dive, at your safety stop, start handing 1 lb at a time to your dive buddy until you feel neutral with no air in your BCD.
 
Well, maybe I was using it wrong after reading the instructions, but Optimal Buoyancy Computer was off for me.

Would you fill in your data, save the file and send it to me or @rsingler together with your real weight needs so that we can have a look?? I think @rsingler would be very interested to study such cases.

Thanks a lot in advance
 

Back
Top Bottom