I now have around 20 dives (maybe more) with my drysuit and it feels much less like a ziplock, which is pretty good. I have been able to control the air bubble. I am getting better with the ascent part ; just to think about it ahead.
Yet, I really hate the queeze on my legs. Only because back kick is really difficult compared with my wet suit. I dove the A.E Vickery couple of weeks ago and I was so happy I didn't go for my drysuit. I felt so much at ease.
Is there something I am missing ? Maybe a crushed neoprene would be a better option for me? (I have a Bare Trilam)
The paradox of diving a drysuit is that while one can dive more comfortably that is a relative term/perspective.
With a drysuit, comfort comes with being warm and dry but there is more to focus on all around than diving a wetsuit. With a wetsuit you don't have to worry as much about trim, about weight vs comfort, etc. With a drysuit there are lots of little factors that you have to maintain awareness of that add up in the aggregate, but with a wetsuit, you can dive head down/feet down if you wish with little to no consequence and your weight for a given suit will change very little (relatively as the suit is used/ages you may need less lead because the suit becomes less buoyant from repeated compression but it also provides less thermal protection too).
What you are experiencing is normal. The bubble of air is going to rise to the highest point in your suit, it is difficult, especially when first learning to dive a drysuit, to keep the air where you want/need it. Keeping air around your legs to keep the squeeze off and keep them warm can indeed be difficult...it helps to dive in what I call the skydiver position with your knees bent and fins parallel with your back in relatively horizontal trim.
With most drysuits the air bubble is relatively free to shoot around, and it moves rather quick to what seems like small changes in body position, as you gain experience you start to refine your body movement and control and are able to adjust your position withe smaller and smaller movements that will have the bubble moving with a bit more control in your suit. You will also begin to feel when the bubble starts moving and can take corrective action to keep it under control and positioned where you want it.
You will rarely if ever have your suit inflated evenly all around from your neck to your toes, and any part of your body lower than the rest will feel a bit of squeeze. The thickness of your undersuit will play a role in how much you feel or are affected by that squeeze as a thicker undersuit will provide padding against the squeeze of the suit.
The difference between diving wet and diving dry is a trade-off between on type of comfort vs another. As mentioned, a wetsuit is much easier to dial in and dive (especially at the beginning), but depending on where one dives it may limit the season, a drysuit on the other hand can keep you toasty and dry but is more work and has a steeper learning curve.
I dive a an Aqualung Fusion Bullet...it is membrane suit with an overskin in 1mm neoprene. The neoprene is primarily to protect and streamline the suit to the body. I find that because of the neoprene outer layer keeping the drysuit layer more form fit, the air bubble in my suit travels around much slower than with other types of suits. This made learning to dive a drysuit a bit easier...but there was still a learning curve. Not everyone likes the Fusion suits...from my reading, most either love or hate them. I really like mine. You might want to look into them as possible solution to the problems you are experiencing.
Diving dry can be very comfortable, but I don't think it is as comfortable as much in the ways many people who have never dived dry expect it would be. Despite being familiar with using a surface drysuit (whitewater kayaking) I had this idea that I would don my drysuit and dive enrobed in a bubble of air. That thought quickly dissipated from my mind after my first dive in a drysuit.
As others have mentioned there are 2 schools of thought on buoyancy management with a dry suit. One school is to use the BCD for buoyancy and the suit for comfort, the other is to use the suit for comfort and buoyancy. While there are pros and cons to both the reality is that if you add air or release air from your suit that it has an impact on your buoyancy...how much of an impact is dependent on how much air is add or released and how deep or shallow you are in the water column. I find that above 20 meters I need to add air to my suit to prevent squeeze and provide warmth, this same air is balancing out my buoyancy so that I am neutral in the water column, I don't have to add air to my wing to compensate because the air in my suit is doing double duty. Below 20 meters the changes in buoyancy as one descend become increasingly smaller because the relative change in pressure around the diver are smaller...I find that below 20 meters I don't necessarily have to add more air to my suit to offset squeeze and provide warmth, so instead at that point I start adding air to my wing to manage buoyancy.
It is also important to note that changes in your undersuit can have a dramatic affect on the buoyancy of your suit as the volume of air trapped in your undersuit will provide positive buoyancy, especially at the beginning AND end of the dive. This affects how you weight yourself. You should be carrying enough ballast to be able to maintain neutral buoyancy at your safety stop depth
with the level of comfort you desire. The level of comfort you desire is an important decision because if you are underweighted for your cold tolerance you will have a hard time staying down for the safety stop, as divers figure this out they sometimes have to resort to cradling a rock or two in their arms to counteract being too positively buoyant. You need to figure out how much air you need in your suit for a given water temperature with your tank at whatever volume you plan to end the dive with along with how much weight you need to counter that to be neutrally buoyant. Be sure to make notes in your dive log regarding end tank volume/pressure, type of tank, what undersuit you wore and water temp...all that information will eventually be second nature to you but until then your dive log will be a great resource to help you figure out how much lead you need to wear.
-Z
