Overweighted at beginning of dive but underweighted at end in shallows

[rx7diver]

The most reliable to weight yourself is Dr Bob's weight titration. With arms and legs crossed (to prevent sculling and finning), a full tank, bladder completely empty, and breathing normally, keep adding weight at 1 pound per inch above water, until your head is just awash. Exhaling should start your descent. This allows for all the weight you need at your safety stop.

I learned, and still use, and still recommend, a slightly different approach when diving a wetsuit: Wearing full gear with completely empty BC, and full cylinder, and wetsuit (including hood and gloves and booties) completely flooded (but without reg or snorkel in your mouth), assume a vertical position and take a deep breath and hold. Without kicking or sculling, you want to float at eye level. You might add/subtract weight, one lb at a time, for each inch the surface is below/above your eye level.

Weighted per above, when you exhale you'll *slowly* sink. But you're never at any time too negatively buoyant to relatively easily remain at the surface even with a completely empty BC, full cylinder, and all your gear (including weights) in place! You can always breathe off your snorkel (so that your head can be entirely below the surface) for additional comfort, especially if you need to make a tough surface swim to safety. Use your surface float if you need additional flotation. Jettison your weight belt at the surface if you have to.

Adjust (decrease) your weighting after a few dives if you "need" to. Don't forget the option of using a competent surface dive to commence your descent, especially if your wetsuit is very buoyant.

NOTE: I learned in freshwater, wearing a 1/4" farmer John and shorty (and hood and gloves), BC, and an old-school steel 72.

rx7diver

 

[The Chairman]

NOTE: I learned in freshwater, wearing a 1/4" farmer John and shorty (and hood and gloves), BC, and an old-school steel 72.

I learned in the summer of '69 in a bathing suit, no bladder, no SPG, no Depth Gauge, and no 'octo'. The tank was off of a helicopter, and we had to drill and tap for a tapered j-valve. To be completely candid, my depth gauge was a red ribbon. I was afforded the luxury of adding or subtracting air to a BCD to fine tune my diving. You were either weighted right, or you had to fight the entire dive.

 

[inquis]

Don't forget the option of using a competent surface dive to commence your descent, especially if your wetsuit is very buoyant.

Sorry, but no. You want to be able to stop your ascent at any depth. If you have to surface dive to get down at the beginning of the dive, you will cork (or have to invert & kick down) at the end of the dive when you're 5-6 lbs even more buoyant.

 

[rx7diver]

Sorry, but no. You want to be able to stop your ascent at any depth. If you have to surface dive to get down at the beginning of the dive, you will cork (or have to invert & kick down) at the end of the dive when you're 5-6 lbs even more buoyant.

Hmmm. I actually do this all the time, especially if I descend for a second dive (repetitive dive) without having changed to a fresh cylinder.

Also, you might not be able to get all the air out of your wetsuit before you ascend. (Some wetsuit inside linings stubbornly hold on to air. That stubborn air will be gone, though, after you've been at depth awhile.)

Also, some wetsuits will compress quite a bit as you descend to 10 or 15 ffw.

rx7diver

 

[The Chairman]

Sorry, but no.

I'm going to agree with you, though there are many different ways to dive. Whatever works for you, simply works.

Personally, I will almost always breathe myself down and then back up. I might kick on a hot drop over a wreck, but I always start my dive neutral. Easy down, easy up. Always in Zen mode. It is the way.

 

[Derbdiver]

Hi all,

Recently went to Curacao and I'm not sure if it's just a matter of figuring out my new gear or what but I figured someone here might have some insight. Many of the dives there seem to have to the later 1/3 of the dive in the shallows where we ran the tanks relatively low at the end of our hour given we were only a few meters from the surface. Using AL80's and I was using a 5mm wetsuit but I found at the beginning of the dive I would be overweighted and have to put a fair amount of air in my BCD to level out at ~20-25m. That was relatively fine as I prefer to be a bit overweighted for initial decent. This issue is that for the end of the dive, with a bit of waves, it was a real struggle to maintain that 4-6m of depth and not just float to the surface. I drained all the air in my BC from every valve and even tried rotating my body around to get any last bits of air but no matter what I did I would just start floating up to the surface on my inhale.

Not sure if this is just one of those thing where there's nothing you can do but wondered if anyone had come across this and if they had any solutions.

For reference I am ~185 lbs and was using 14lbs of lead

Thanks in advance.

NN

Another option is to dive with Steel tanks. They are negatively buoyant always, hold more pressure in smaller size. Downsides are they can corrode if not taken care of and heavier. Another option is to use a weighted back-plate style BCD for warm water. I never wear more than a dive skin .5mm in tropical waters. I did grow up swimming and diving in a large northern lake so I don't get cold unless the temp drops below 62F.

 

[tursiops]

Another option is to dive with Steel tanks. They are negatively buoyant always

Irrelevant. They still get lighter when the gas in them gets used. The buoyancy swing doesn't care what the material of your tank is.

 

[Derbdiver]

Irrelevant. They still get lighter when the gas in them gets used. The buoyancy swing doesn't care what the material of your tank is.

Strange, I have one 120 Steel and one 100 Al. With both empty the Al floats, the Steel sinks.

 

[Derbdiver]

Strange, I have one 120 Steel and one 100 Al. With both empty the Al floats, the Steel sinks.

You can always read this since you give no credence to my post.

Steel vs Aluminum Scuba Tanks: Which One is Best? - Scuba.com

Before you buy your own air cylinders, take a look at tips you'll want to consider when choosing steel vs aluminum scuba tanks.

www.scuba.com

Nice Little chart here:

 

[BRT]

Strange, I have one 120 Steel and one 100 Al. With both empty the Al floats, the Steel sinks.

The buoyancy change is the same per pound of air used. You start out with less lead. Easy to identify a full HP 100 vs an empty one by lifting them both.