Is buoyancy control more difficult with a thicker wetsuit?

[FPDocMatt]

With a 3-mm neoprene wetsuit in 81-degree water at Grand Cayman I had pretty good buoyancy control, if I say so myself.

This week with a 5-mm wetsuit, and a 5-mm shorty over the top of it, in 60-degree water at Gibraltar, my buoyancy control sucks. Is it that thicker wetsuits are harder to maintain neutral buoyancy with? Could it be that colder water is more difficulty? I had aluminum tanks in the Caribbean, and steel tanks in the Mediterranean.

Or perhaps it's just that this week's dive was shallower than before, since I was doing the AOW navigation exercises in only 7 meters of water.

 

[Blue Sparkle]

I would say yes, because a thicker suit will have more variation in buoyancy than a thinner suit or no suit at all. Too, it would be more noticeable at around 24' where you were diving (at deeper depths it would just compress and stay that way in a more consistent way).

Also, it's possible your weighting was not as spot-on as it was with less exposure protection and/or a familiar tank/etc. That could also cause more fluctuation because, say if you were overweighted slightly, you would put a bit more gas in your BC, and then that gas would have more variability as you changed depth during your dive (in addition to the neoprene itself).

The first time I dived with no exposure protection at all, which was at around dive #18 for me, was the first time I really felt like I "got" my buoyancy. I don't know when that would have happened if I had still been wearing an exposure suit - and it was also the first time I had my own gear - but I can say that it suddenly felt very "simple and solid" as compared to wearing neoprene on previous dives.

Blue Sparkle

 

[Teller]

In my opinion it is easier to control bouyancy with thinner exposure suits and light AL tanks then it is in thicker suits and steel tanks. I would much rather dive in warm water with a 3MM wetsuit and AL80 then cold water with a 5MM and steel tanks. If you think your bouyancy with a 5MM needs work then use your 5MM more often. Your bouyancy will improve over time.

 

[dumpsterDiver]

yes it makes a huge difference. If you ever dove without any wetsuit, or a non bouyant skin, you will be amazed at how damn easy it is. You don't have to mess with the BC at all except maybe to dump a little air toward the end of your dive as the tank gets lighter.

If you are weighted right (without a wetsuit) you will have less than 5-7 lbs of bouyant air in the BC when underwater. If you start to come up and forget to dump it, it may expand 50% before you notice... big deal.. now you are 3 lbs bouyant.. very simple to fix, dump little more than a fart from your BC.

Now dive with a thick suit... You have much more lead and when you get down the suit crushes a lot, losing 15 or more lbs of bouyancy at depth.. so... you have maybe 15 - 20 lbs of air in your bc to be neutral... what happens when you ascend? Your suit expands (increasing bouyancy) and the much larger volume of air in the BC expands the same relative amount, but since you started with much, much more air in the BC, the expansion is much, much more.

The wetsuit and the air in the BC represent an unstable equalibrium... Once you are balanced it is immediately thrown off when you descend.. you get heavier faster and when you come up you get lighter faster.

This is why, all things being equal, you want to generally wear the LEAST amount of wetsuit, that will keep you warm and protected.. hint: that is why hoods are so cool. alittle bit of rubber, but a lot more warmth.

 

[Splitlip]

Water depth also contributes to the difficulty factor

 

[5280diver]

Steel tanks are more negatively buoyant. And all the weight you had on with the 5mm is going to make it a lot harder to control your buoyancy specially if you are use to diving a 3mm

 

[TSandM]

Yes! DD has described why; in minimal exposure protection, you have ONE expanding air collection (your BC) to manage on ascent, but with thick neoprene, you now have TWO. In addition, in warm water, with little neoprene, you carry very little weight and lose very little buoyancy at depth, so you never have much air in the BC to begin with. In cold water, you lose a LOT of buoyancy as you descend, so you're carrying a much larger air bubble in the BC, which means you really have to be on top of buoyancy changes to make sure you vent early and enough.

But cut yourself a little slack . . . you went from one gear configuration to something quite different, and were attempting to do skills in shallow water in the new gear. Even for experienced folks, it can take a dive or two to shake the bugs out of a new setup. You'll figure this out!

BTW, the tanks make no difference in buoyancy. If you are weighted correctly, it doesn't matter if you're carrying lead to sink an aluminum tank, or just using a steel tank. Where steels can cause issues is with rotational stability. But for buoyancy, the only problem with steels is avoiding being overweighted.

 

[Splitlip]

Yes! DD has described why; in minimal exposure protection, you have ONE expanding air collection (your BC) to manage on ascent, but with thick neoprene, you now have TWO. In addition, in warm water, with little neoprene, you carry very little weight and lose very little buoyancy at depth, so you never have much air in the BC to begin with. In cold water, you lose a LOT of buoyancy as you descend, so you're carrying a much larger air bubble in the BC, which means you really have to be on top of buoyancy changes to make sure you vent early and enough.

But cut yourself a little slack . . . you went from one gear configuration to something quite different, and were attempting to do skills in shallow water in the new gear. Even for experienced folks, it can take a dive or two to shake the bugs out of a new setup. You'll figure this out!

ted.

Which is why any gear changes, particularly wetsuits, I do shore dive at BHB first. Further, I also try to get an easy ocean dive in before my usual venue.

More important than writing "I saw a pretty fish" in your log is to record weight, exposure protection, cylinder etc.

 

[dumpsterDiver]

Without a wetsuit, if you are reasonably attentive, if you begin to float up, you don't even need to touch the BC, all you have to do is just exhale hard... That will dump more air/buoyancy than the expanding BC represents and this gives the novice a chance to bobble around and locate the inflator/deflate location and dump some air and start breathing again, especially if you are down below 30 feet or something.

In other words, you can use your lungs to compensate (to a large degree) for inattentiveness toward buoyancy control. This technique (of screaming shiitttttttttttt!) doesn't work in a thick suit, in shallow water.

If you don't dump the BC when you need to, the opportunity to regain control is quickly lost.

 

[Eric Sedletzky]

When you get into really thick suits like 7mm - 9mm and the material is spongy, this is where buoyancy is a real challenge.
The crush factor at depth can make you really heavy even when you weight yourself absolutely as light as possible so that you can just hold a stop at 15 feet with no air in your wing.
I had a few custom suits made out of a much denser material and harder to crush which helps but they still crush down and I get heavy although not as bad.
The tank makes no difference, like TSandM mentioned you just adjust your weights according to the tank you're using. 6 lbs. of air used is 6 lbs. of air used regardless if it's in a steel or an aluminum tank.