Weight Calculations

[Indian Valley Scuba]

I'm not exactly sure where that comment came from, unless you looked at one photo of me wearing such a set up and made an incorrect assumption.

Read what I said, which you copied and pasted in your comment, with regards to the environment and the tank I referred to.

Not sure of the definition of "standard basic openwater scuba gear" but I didn't think that precluded wearing a backplate. In fact, if you look at our photo gallery, you'll see quite a few of our open water divers in backplate systems! But just in case, I did mention the negative buoyancy of that item.

Thank you.

 

[muddiver]

Great response Arkman, except for that "6 or 7 pounds" comment.

It is so unfortunate that so many divers are trained to be overweighted from day one. It is a curse that is carried, literally, on every dive. "Less is more" is the key in adding lead.

Some of the reasons instructors over weight students, and I don't agree with the reasons, are to 1) keep the students from corking in shallow water during training, 2) allowing the excited students to sink when they reise the BCD inflator hose and press the "down" elevator button.

Personally I can't do a slow submersion in the standard PADI upright position because to be corretely weighted at depth I am actually buoyant on the surface. For me correct weighting is neutrally buoyant at 20 or 40 fsw in a 7 mil farmer john wet suit. To sink from the surface the way a lot of instructors teach I would have to add 2 to 34 lbs and then I would be filling my BCD half way to keep off the bottom.

 

[muddiver]

I'm not exactly sure where that comment came from, unless you looked at one photo of me wearing such a set up and made an incorrect assumption.

Read what I said, which you copied and pasted in your comment, with regards to the environment and the tank I referred to.

Not sure of the definition of "standard basic openwater scuba gear" but I didn't think that precluded wearing a backplate. In fact, if you look at our photo gallery, you'll see quite a few of our open water divers in backplate systems! But just in case, I did mention the negative buoyancy of that item.

Thank you.

Instead of changing the peramiters I laid out and bashing the rule of thumb I offered, why didn't you just simply state that in your-neck-of-the-woods everyone uses a back plate and wings, and then just subtract the weight of the back plate from the final "rule of thumb" answer to get a rough idea of a starting weight.

Most scuba training agencies only require a cylinder, a regulator with a second 2nd stage, a BC, mask, fins, weight belt, SPG, depth guage, timer and the appropreate exposure protecton for a basic scuba certification class. I know of no agency at the basic recreational level that required students to use a stanless steel back plate. I am just thinking globally, and the largest training agencies that crank out the most students don't promote the really good technical diving spin-offs like PB/W and doubles.

I respect your shop, you guys offer a lot of stuff that no other shop would ever consider, like rebuild kits.

 

[muddiver]

I concur. That would call for 20 lbs. I wear about 8 with a 3mm full.

With a steel 100 in salt water I use zero weight with a 3mm full. Could maybe get by with a 2lbs max.

I qualified my statement that it is a "rule of thumb" for a 6 mil or 1/4" wet suit.

Why are you changing the peramiters and making an argument.

I also only use 8 lbs with my 3/2 in warm water, and only 4 or 5 lbs in fresh water.

 

[Indian Valley Scuba]

OK OK OK ...I think we're all on the same page here! Thanks for the clarification...and the compliment!

 

[fisheater]

For what it's worth, I found that there was a ten pound difference switching from my Zeagle BC to a DSS backplate. 5 pounds of which was the steel on the backplate and the remaining 5 pounds was the padding on the Zeagle.

YMMV.