Weight Calculator

[Viron]

Its a balance youll have to estimate and Id go a bit heavy so you can hold a safetystop at 20 ft with 5 - 700psi in your tank. Idealy, with a full breath holding in your lungs, you should be able to float at eye level with 700psi!

A normal floater is probably someone who doesn't breath normally in water. That is, a floater is someone who probably breathes in full deep breaths and never fully exhales. A full or near full exhale is normal breathing. A full inhale is not normal breathing.

When don't exhale fully you are more bouyant and you want to breath more because you never fully exhale the dead air rich with CO2.

The downside is higher air consumption which means less bottom time. Bottom time is why we dive.

Even though I'm a NB after listening to my brother with 30+ years experience I've been able to get my air consumption below .4cuft/min. In other words I use a little more air than HALF the air of the average diver, which means almost twice as much bottom for the same air tank and boat ride. When the pack is up in 30 min I might be 45-50 min, and have more reserve in my tank.

 

[nolatom]

I (an English major) look in my logbook and use whatever weight I wrote was "okay" last time, for the same getup ;-)
Works for me, especially if you made a note of, for example "12 lbs too much, second dive 10 lbs, good".

I know this isn't a formula, but just sayin'..

 

[tursiops]

this thread is almost 4 years old....

The "calculator" folks are complaining about is actually a table in the PADI Open Water manual, also in the AOW manual and the Peak Performance Buoyancy manual. It is actually not bad if used correctly, but rarely is. For example, you do not add 6 pounds to go to saltwater, because the table is already for salt water. (You subtract 6 pounds if going to freshwater) It assumes an AL80, so if you use steel you need to add less weight. Etc. The table also clearly says it is for someone with a normal build, so all this concern about floaters and sinkers is valid, but the table is not for them.

 

[Altamira]

Estimated Diving Weight Calculator | DiveBuddy.com
This calculator works well for me and my wife for both salt and freshwater, and it gives a little +/- flexibilty. It does not have every tank size/composition that is available in the market, but I found the estimated weight requirements to be very close to what we actually needed. Of course nothing will be as accurate as thorough, properly accomplished "in the water" weight checks with the equipment you will actually be using. However, unless I want to lug around my own weights on dive trips (which is not feasible most of the time) I find I am usually forced to be a pound or two overweighted on boat dives because I have to use the weights available on the boat, and the exact weight combination I need is not always possible.

 

[Patoux01]

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

 

[Neilwood]

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

The calculators might not work for you but, in the absence of a proper weight check (as per the OP's request due to the fact that he can't do a weight check in the rented equipment until there), they can at least get someone in the right ball park with regards to a weight that will at least keep them down.

The fact that, with experience, it might be possible to use less weight is well known and accepted. More experienced divers that know this fact will also probably have done enough dives that they will be able to more accurately estimate the weight requirements (and how their body differs from the calculators suggestions)

 

[tursiops]

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

I'd really be curious what data you put into the calculator and the PADI table that gave you such a wrong answer. Can you elaborate?

 

[scubadada]

I was interested and tried the calculator. It was pretty far off, especially with thinner wet suits. I entered 185 lbs, expert (increasing experience lower suggested weight), 3, 5, and 7 mm full suit, AL80, salt water. I wear a back inflation BC. I often wear a hooded vest with any of the full suits.

Wetsuit Calculator Actual
3 mm 14-18 lbs 7-8 lbs
5 mm 17-21 lbs 13-14 lbs
7 mm 20-24 lbs 19-20 lbs

So, it's way off at 3 mm, double the actual weight I use. It gets closer at 5 mm, about 25% over, and is just a bit off at 7 mm and the range just overlaps the actual.

Sorry about formatting, could not get it to import Excel correctly

 

[Neilwood]

I wonder if part of the reason for the differences is BCD type - older jacket type BCDs are very buoyant whereas newer styles and BP&W types are nearing neutral or negative

 

[scubadada]

I wonder if part of the reason for the differences is BCD type - older jacket type BCDs are very buoyant whereas newer styles and BP&W types are nearing neutral or negative

Interesting that the error is so much greater with thinner wet suits