How much weight do i need ?

[lerpy]

I found when I started learning that you seem to overweight yourself in the beginning. As I got more experience and adjusted my gear I found I was able to drop weight. Do a weight test on every dive and keep track of how much weight you need, and what gear you are carrying, and then as you progress and get more comfortable start to take a bit of weight off. You will actually find the less weight you require the better your trim and diving will be in general, or at least that is what I have found. As well if you happen to get into a backplate and wing set up, really get good advice on the wing based on your gear and needs. I had a wing that was way to big as I thought I needed it for the large doubles I moved to. I took a course and the instructor recommended a smaller wing, which I got and I have a much easier time controlling my buoyancy now. It's a learning process.

 

[boulderjohn]

Your instructor should have a good answer for you, however here is a rough estimate that I use.

10% of body + enough to counter act gear.
(add more if using drysuit)
(add 6lbs if in salt water)
(if using sidemount do not count weight for tanks as personal weight.)
(if using doubles you'll need less weight)
(if using al tank you'll need about 4 more lb per tank)
(if using steel tank see tank specifications for weight)

If I used that formula on my last trip, I would have used 34#. I needed 4 to hold a safety stop with 300 PS1 in my tank.

I agree with hroark2112--this formula can grossly overweight you. I dive with a wide variety of configurations, and running the amounts of weight I use for each combination, I determined that on average, this formula overweights me by an average of 20 pounds for each.

For example, back when I used to use a standard BCD instead of a BP/W, when I dived in the ocean with an AL 80 tank, I used 8 pounds of lead, and I was just a little overweighted. According to the formula, I would have used 32 pounds--more than 24 pounds overweighted.

As a second example, this coming weekend I will be diving in fresh water in a dry suit with steel doubles and an aluminum backplate, which weighs less than a standard BCD. I will be overweighted while carrying no lead whatsoever.

 

[Hawkwood]

Since this was a question about pool use and no doubt the Poster has had it figured out by now, I will still through my 2 cents in.

Usually my students start off CW1 with a simple 5%, less whatever I "eyeball" - i.e. lean or not so lean (bioprene). We get a pretty good idea as soon as they are doing the first set of skills were the weighting should be.

Invariably when they do the "proper weight check" on CW2, they discover they need no weight at all - freshwater pool, 63cf tanks, jacket-style BCDs, and maybe a 3mm shorty wetsuit (most of which have lost all semblance of buoyancy).

Hey everyone. So today I started my first open water swimming in pool class and I had to put some weight. The trainer told me put what ever makes you comfortable. I've put two big and two small weights on the belt. ( I don't know know how many kilos/pounds they were) I started to sink fast even when I put air in the BCD.

I weigh 255 lbs/ 116 kilos
How much weight do I need in order to be in a good position instead of sinking in the water.

​Regards,
Salah

 

[hroark2112]

The funny thing was my first dive in Little Cayman. There was one of "those guys" on the boat who felt the need to "help" me with my weighting. He told me I wouldn't get underwater with less than 24#. I waved to him as I went under with 4.

I'm pretty sure he had well over 20# on him and it showed in the water. He was kind of a flailing muppet!

 

[wspalding]

Hey everyone. So today I started my first open water swimming in pool class and I had to put some weight. The trainer told me put what ever makes you comfortable. I've put two big and two small weights on the belt. ( I don't know know how many kilos/pounds they were) I started to sink fast even when I put air in the BCD.

I weigh 255 lbs/ 116 kilos
How much weight do I need in order to be in a good position instead of sinking in the water.

​Regards,
Salah

Based on your description of "2 big and 2 small weight" I'm guessing you had about 16 lbs of weight, which is probably too much. Your instructor should be providing guidance on where you should start on weighting, it's kind of silly to have a new student guessing at their weight requirements.

 

[REVAN]

The answer is that you want to dive with no more weight than necessary and you will need to learn what that is and how to keep track of how it changes with your gear configuration changes. Your instructor should be showing you how to do this. If he/she tries to tell you to just make sure you have enough to know you will definitely sink and then use the BC to compensate, they are not teaching you to dive. They are only teaching you to sink.

Little things to know:

An 80 ft^3 tank will gain about 3.75 pounds of buoyancy as the tank empties to normal end-of-dive status (about 1/6th capacity). Buoyancy characteristics for any tank can generally be found in the manufacturer's specs. Look those numbers up and know them. Steel tanks are going to be more negative than aluminum tanks, but the change in buoyancy of any given tank is determined by the amount of air that leaves the tank during the dive and has nothing to do with the material from which the tank is made.

A typical person will have about 7 to 8 pounds of buoyancy variation just from inhaling deeply. If you can't get down, try exhaling. There are only two reasons why new divers need more weight to get down with neutral buoyancy than an experienced diver. (1) they are having trouble getting the air out of their BC. (2) they cannot overcome the impulse to take in a deep breath when going underwater. The second reason is usually the big culprit.

Whatever buoyancy your dive suit has at the surface will be cut nearly in half at 10 meters depth. It sounds like this won't have much impact on you as you are diving warm water.