Weight Calculator

[fjpatrum]

I recall using the PADI weight calculator and being off by 10+ pounds for my OW dives in class. It suggested I start with 26 pounds for a 7mm 2 piece suit and I ended up needing 14.

With a BP/W I now dive pretty much any configuration, from 3mm up to dry suit, with a max of 4 pounds. Count 6 pounds for the plate and STA and it's still off by a ridiculous amount.

 

[Altamira]

All those calculators are crap.... 15 pounds off, that's a 100% difference in my case. The PADI gave some crappy value as well...

Please stop spreading these pieces of junk

Why not just say the various calculators do not work for you instead of being so dogmatic. I found the calculator that I cited above after I had already established my actual weight requirements by doing a weight check on every dive and documenting the information in my log. I was pleasantly surprised that particular calculator's weight estimate came very close to my requirement with my particular dive gear. Same for my wife's weight requirements. While no weight estimator is going to nail the correct number for every diver in every situation, with every gear configuration, they do give a new diver a start point from which to work and fine tune weighting. Also, I think many divers do not give adequate consideration to such things as fin and bcd buoyancy, as well as the weight/bouyancy of flashlights, smb, reels, and other safety equipment, when evaluating actual weight requirements.

 

[Neilwood]

Why not just say the various calculators do not work for you instead of being so dogmatic. I found the calculator that I cited above after I had already established my actual weight requirements by doing a weight check on every dive and documenting the information in my log. I was pleasantly surprised that particular calculator's weight estimate came very close to my requirement with my particular dive gear. Same for my wife's weight requirements. While no weight estimator is going to nail the correct number for every diver in every situation, with every gear configuration, they do give a new diver a start point from which to work and fine tune weighting. Also, I think many divers do not give adequate consideration to such things as fin and bcd buoyancy, as well as the weight/bouyancy of flashlights, smb, reels, and other safety equipment, when evaluating actual weight requirements.

Agreed - there are so many variables in these calculators that it would be impossible to come up with one that gies the perfect answer every time. What they do give is a good starting point which can be adjusted based on experience/knowledge of kit (ie BP&W offsetting some of the buoyancy, -ve fins etc)

 

[Diving Dubai]

Okay I tried this also

So for me Plateless wing, weigh 205lbs (95kgs) at 6'3 wearing 4mm boots

The 10% method is 9kg (18lbs)

The calculator above set to advanced not expert and salt water

Using a 3mm suit and HP 120 cylinder claims 14lbs (7kg). Actual weight is 0

Using a 5mm suit and HP 120 cylinder claims 18lbs (9kg). Actual weight is 6lbs

Using a 7mm suit and HP 120 cylinder claims 21bs (11kg). Actual weight is 8lbs

Dry Suit (novice at the moment) 10lbs

My 15l steel (HP120) is -4 neg a the dive end and and AL 80 is +4 So in theory if I use the 3mm suit calc but switch to Al 80 it should add 8lbs. It doesn't it only adds 4!


I appreciate @Neilwood comments about less experience people needing more weight and BCD are more inherently buoyant than wings but still.... Pehaps its designed by someone who is used to diving overweighted

 

[Neilwood]

Diving

Okay I tried this also

So for me Plateless wing, weigh 205lbs (95kgs) at 6'3 wearing 4mm boots

The 10% method is 9kg (18lbs)

The calculator above set to advanced not expert and salt water

Using a 3mm suit and HP 120 cylinder claims 14lbs (7kg). Actual weight is 0

Using a 5mm suit and HP 120 cylinder claims 18lbs (9kg). Actual weight is 6lbs

Using a 7mm suit and HP 120 cylinder claims 21bs (11kg). Actual weight is 8lbs

Dry Suit (novice at the moment) 10lbs

My 15l steel (HP120) is -4 neg a the dive end and and AL 80 is +4 So in theory if I use the 3mm suit calc but switch to Al 80 it should add 8lbs. It doesn't it only adds 4!


I appreciate @Neilwood comments about less experience people needing more weight and BCD are more inherently buoyant than wings but still.... Pehaps its designed by someone who is used to diving overweighted

I think you and I would both have similar issues regarding the calculators - we are both outwith average height (6'3 here) so that makes the weight within the calculation a dubious issue. Someone at 5'6 weighing 205lbs will have substantially more bioprene (and therefore buoyancy) than someone at 6' and the same weight - therefore huge weighting differences.

At best a weight calculator can only be seen as a best guess as it can only ever work on approximations and averages (unless it is adapted to ask

The only way to eliminate that would be to add in some way to measure body composition (BMI not suitable as it takes no account of fitness/body type etc), makes the calculator far more cumbersome and and gets away from the point of an "Estimated Weight Calculator". The whole idea of them is as a guide not as a rule.

The only way to know your weighting is to actually do a proper weight check in the water but in the absence of that the OP needed a way to estimate his weighting requirement and that was what was provided. Whether that weighting is accurate (for him) or not will only be known with a proper weight check.

 

[Patoux01]

I'd really be curious what data you put into the calculator

I'm 74kg, use 3# in salt water with 3mm and 2 aluminium tanks. This thing suggested 14# (+-1).
7mm? 19# (+-2), I used about 12. (again, 2 al tanks)
drysuit with light undergarment? 24#, I used 12 again. (same tanks)

Didn't get the PADI one again, I thought it was also in the OW book but can't find it. Threw away my AOW one a long time ago, but when I read it and checked against my weighting during the dives it was way off.

So yeah, the name crapulator is definitely correct.

As to why I'd like people to stop promoting them? Well, I don't like those zeppelin redundant wings, so if I jump in with my 2 al tanks in a 3mm suit, I'm gonna be close to 25# heavy when my wing fails me. With my weighting, that's gonna be 13# heavy. In one case I can swim up without too much trouble, in the other, not so much.


Basically, my point is: If your starting point is gonna be "sink like an anchor", you don't need a calculator to tell you how to do that . As a starting point, I consider it much safer to start at 0 than "way too much". My guesses usually aren't too far off, I can only imagine it should be the same for other divers, especially if you're gonna dive with an instructor that's supposed to help you out