Weight

NoviceDiver1 · Dec 7, 2013

Hi Guys,

I am diving with a 12mm. 18 pounds seems to be the right weight for me (no air in bcd at safety stop) however, I have hard time getting through the first 10 feet. If I increase the weight I go down properly, but then I am heavy at any depth past 10 feet. I am wondering if there is a good way to deal with this inconvenience. Any useful suggestion will be greatly appreciated.

pasley · Dec 7, 2013

12mm? Wow. And our local divers complain about 7mm. What water temps you diving in 40f? 1st suggestion is check your feet. Many newer divers have trouble with the first few feet because they are unconsciously slowly moving their fins back and forth propelling them up not down. Thy crossing your ankles when you start to descend.

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NoviceDiver1 · Dec 7, 2013

pasley:
12mm? Wow. And our local divers complain about 7mm. What water temps you diving in 40f? 1st suggestion is check your feet. Many newer divers have trouble with the first few feet because they are unconsciously slowly moving their fins back and forth propelling them up not down. Thy crossing your ankles when you start to descend.

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...High 60s..at that temperature after 40-45 min I start shivering with a 7mm

Crossing the ankles is an excellent idea, will give it a shot next week. Thanks a lot.

Vegan Shark · Dec 8, 2013

What tank are you using? I wear 12 mm, and 18 lbs too. Steel 130 here. How about simply rolling forward at surface and swimming straight down to get past the first 10 ft, rather than passively sinking feet first.

TSandM · Dec 8, 2013

There are a number of reasons why you might have trouble initiating descent. To begin with, your neoprene is as expanded as it's ever going to be, at the beginning of the first dive. In addition, there may be some air pockets trapped in the suit that will work their way out while you are diving.

In addition, you've already had pointed out that any kicking you are doing while you are at the surface will drive you upward -- and it's very common for people not to feel very stable at the surface, and to kick constantly to maintain an upright position. Crossing the ankles and bending the knees slightly will have two nice effects -- it will prevent you from kicking upward, and the water will catch your fins as you descend, and rotate you immediately into a nice, horizontal position for your further descent.

In addition, most of us were taught to exhale as we pushed the bottom to let the air out of our BCs. If you do that, it's likely that by the time your head starts underwater, you will need to take a breath, which will then push you upward. Better is, as you depress the exhaust button on the BC, to take a deep breath and hold it (yes, you can hold your breath when your head is OUT of the water!). Then, as your head gets close to or at the water level, exhale sharply, and then exhale a little more. That big exhalation will carry you down through the top three feet or so -- by the time you have to inhale again, you will be underwater and already enjoying the effects of a little suit compression and the venting of any air pockets.

Phil_C · Dec 8, 2013

I have glide-seal internal baffles in the arms and legs of my wetsuit (a 5mm) that means that once full, the water doesn't move about much but also that until a few minutes into the dive it does exactly what TSandM says and traps some air. Add to this gloves fitting closely over the wrists and booties tucked in and you will certainly be carrying bit of unwanted air for the start of the dive.

I do similar to TSandM suggests, either a tuck dive and swim down, however if I do want to go down feet first for any reason (usually if I want to keep sight of everyone around me) when I want to submerge I empty my BCD and do a quick, sharp, fin kick upwards to make me 'bob' up, then breath out hard as you start to come down off the 'bob' and that little bit extra momentum is usually enough to carry me under. Of course after the sharp upwards kick you then have to stop finning or it doesn't work!

Phil

gcarter · Dec 8, 2013

Duck dive to start works for me - along with figuring out the incantation / technique required to get ALL of the air out of my BCD.

chillyinCanada · Dec 8, 2013

I'm a duck diver too. Like Phil when I want to be able to see something like my buddy from the get go then I'll use something similar to TS&Ms practice. But generally that is just slower than I want to go.

Rich Keller · Dec 8, 2013

Vegan Shark:
How about simply rolling forward at surface and swimming straight down to get past the first 10 ft, rather than passively sinking feet first.

I agree, if everything else is working properly for you I would not change a thing and just swim down past the 10' mark at the start of your dive. This is just a minor inconvenience at best. How is it that you are too buoyant at the start of the dive with a full tank but have no issue holding a stop at the end with a near empty tank? What is the weight difference between your tank full and at 500psi? How much extra weight have you added to overcome the excess buoyancy at the beginning of a dive?

NoviceDiver1 · Dec 8, 2013

TSandM:
There are a number of reasons why you might have trouble initiating descent. To begin with, your neoprene is as expanded as it's ever going to be, at the beginning of the first dive. In addition, there may be some air pockets trapped in the suit that will work their way out while you are diving.

In addition, you've already had pointed out that any kicking you are doing while you are at the surface will drive you upward -- and it's very common for people not to feel very stable at the surface, and to kick constantly to maintain an upright position. Crossing the ankles and bending the knees slightly will have two nice effects -- it will prevent you from kicking upward, and the water will catch your fins as you descend, and rotate you immediately into a nice, horizontal position for your further descent.

In addition, most of us were taught to exhale as we pushed the bottom to let the air out of our BCs. If you do that, it's likely that by the time your head starts underwater, you will need to take a breath, which will then push you upward. Better is, as you depress the exhaust button on the BC, to take a deep breath and hold it (yes, you can hold your breath when your head is OUT of the water!). Then, as your head gets close to or at the water level, exhale sharply, and then exhale a little more. That big exhalation will carry you down through the top three feet or so -- by the time you have to inhale again, you will be underwater and already enjoying the effects of a little suit compression and the venting of any air pockets.

Thank you for the excellent suggestions, I think both of these combined will give me this marginal push down I need to descent.

---------- Post added December 8th, 2013 at 09:18 AM ----------

richkeller:
I agree, if everything else is working properly for you I would not change a thing and just swim down past the 10' mark at the start of your dive. This is just a minor inconvenience at best. How is it that you are too buoyant at the start of the dive with a full tank but have no issue holding a stop at the end with a near empty tank? What is the weight difference between your tank full and at 500psi? How much extra weight have you added to overcome the excess buoyancy at the beginning of a dive?

I use a regular AL 80. I think I have this issue because the difference the suit makes when expanded and compressed may be quite significant.
In most cases this is a minor inconvenience indeed, but in some cases it matters. If the waves are 4-6, then it causes significant exertion, which increases heart rate and air consumption not only during the descent, but throughout the dive. In addition, I lose sight of my buddy, which is my wife, and I really do not like that, especially if the viz is low.

Cheers

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