How squeezed is squeezed? (Really wanting to like the Dry Suit)

Spent a whole day this weekend in the water in a Dry Suit - Thanks DUI

My question ... That I couldn't figure out how to ask of anyone in person is, How tight are we supposed to have the suit squeezed? Whenever I added air to the suit, there was usually too much, whenever I didn't add much air, the legs were so tight, that swimming was REALLY tough - I got it done, but, it was tough going.

Was I just not used to diving dry?
There was a great chance that the suit was WAY too big

Any thoughts?

Thanks!

I was told not to add any air to the suit until you get to 15 ft. Get a feel for that amount of squeeze and then add just enough air as you go deeper to mimic it. (Purge excess air before you enter the water though.)

I leave the valve open all the way and fill er up. In time, you'll be able to feel the bubble and know when its too full. Sometimes, I'll even close the valve some and put more air in.

My theory - I want as much gas in the suit as I can and still manage the bubble. That's how you stay nice and toasty warm. Some people like to dive with a bit of a squeeze. I'd rather throw a few extra pounds on and be warmer.

But, when starting out, try to stay shallower and limit the air in the suit until you get more comfortable with it. After a few dives, add a little more and get used to that. Soon, you'll be able to feel when the suit has the right amount of air.

The classic definition of squeeze taught in the 1960s was evidenced by tissue damage. Discomfort was never considered. People new to dry suits are often surprised to the point of alarm how much pressure differential there is in the height of their frame. Once you get used to them you will not notice your exhaust valve dialed back to the minimum pressure.

Fit is very important in a drysuit. If you were participating in the DUI demo, I would have to think that the DUI employees helping you get fitted made sure that you had the right size suit. If this was your first time diving a drysuit, then chances are you just weren't diving the suit properly.

If you were only feeling the squeeze in your legs, then you were vertical.
The secret to diving a drysuit comfortably is to be horizontal during descent, the bottom phase, and ascent.
When you're horizontal, the gas surrounding your entire body inside the drysuit (incl. arms, torso, legs) is subjected to roughly the same ambient pressure. (This is just another way of phrasing Akimbo's point about the pressure differential in the height of a person's frame.)

If you are vertical in a drysuit, you'll naturally feel a squeeze in your legs and possibly your torso as the air inside your suit escapes out your exhaust valve. The squeeze sensation is akin to being shrink-wrapped into your drysuit. To relieve this squeeze, get into a horizontal position and add enough air to the suit to be "comfortable."

Novice drysuit divers are generally instructed to keep a very small amount of gas inside the drysuit to guard against unintentional ascents. It's important to strike a balance between having not enough gas, which can result in uncomfortable/dangerous squeeze, and having too much gas, which is harder to control as it expands during an ascent. What is comfortable will vary from one person to the next. At the very least, a drysuit diver should keep enough gas inside the suit so that he's mobile enough to conduct the dive, i.e., can breathe without restriction, can kick freely, can move his arms freely, etc. It's advisable to maintain a large enough bubble so that the squeeze isn't causing any pain; pain can seriously detract from your enjoyment of the dive. Bear in mind that most drysuit garments need to be lofted with a certain amount of gas to provide maximal thermal insulation. I agree with hypertech's recommendation to learn how to maintain a progressively larger drysuit bubble. Work up to it slowly, though.

A critical issue with learning how to operate a drysuit is ensuring that you are properly weighted.
Before diving the drysuit for the first time, you should have conducted a proper weight check, preferably in a horizontal position in the water.
Understand that the amount of gas you are running inside your suit during the weight check will affect your weighting. I don't like my drysuit to be shrink-wrapped since I get cold easily, so I make sure that I have a generous amount of gas inside my suit during the weight check.
It's helpful to conduct the weight check in shallow water with a buddy who can serve as a lead weight sherpa.

The secret to diving a drysuit comfortably is to be horizontal during descent, the bottom phase, and ascent.

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Bubbletrubble's entire post is spot on, but I want to emphasize this sentence. If your legs are squeezed, they are below the rest of you. This presents significant problems for the dry suit diver, because if the shoulders are higher than the rest of the body, any gas you put IN the suit, will exit through a properly placed dump valve (and DUI puts theirs in the right place). Unless, of course, you close the valve, in which case any ascent at all is going to be extremely problematic. Dry suit divers really need to master trim to be really comfortable.

As stated, when you are new, it's good to keep the gas in the suit to a minimum, but a minimum means the least amount you need to put in to be comfortable and mobile enough to operate your gear. Andrew Georgitsis used to teach the "20 foot squeeze", and I approve of the sentiment, although I think 20 feet is a bit much -- but if you start from the surface relatively empty and get down to about 10 feet and see how the suit feels, you can probably safely dive that "feel" throughout your dive. It won't keep you as warm, and it won't be as comfortable, but it will pose substantially less risk of a major buoyancy oops.

As you become more facile with the suit (and trim and anticipation are the keys) you will be able to run more air in it, if you wish. I use my suit alone for buoyancy, pretty much, with a single tank, and as much as I can manage with doubles. It makes for a warmer and more comfortable dive, but you really need to be able to manage the suit bubble to do that.

Bubbletrubble:

…The secret to diving a drysuit comfortably is to be horizontal during descent, the bottom phase, and ascent...

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I always descent head first in a drysuit and Scuba. My secret is to control the amount of air in the suit and make sure my suit’s legs don’t fit like a pair of lift bags — also described by Bubbletrubble. If you don’t also take care of gas volume and fit, you will forget one day to keep your legs [-]higher[/-] lower than your shoulders… really awkward to trim that way.

Loosely related sea story:
My first really dry dive in a drysuit was in lead-shoe & copper helmet deep sea gear. I had done a lot of Scuba diving by then and a few dives in leaky drysuits that didn’t last very long (late 1960s). I was truly astonished how strong the squeeze was on my calves. Pretty soon, none of us in the class thought anything about it. It is amazing how the brain trains itself to accept alarming sensations.

Deep sea suits have automatic exhaust valves that sets the backpressure in the suit, functionally similar to our modern dry suits. The difference is you set it more to control your level of negative buoyancy so you could walk the bottom but not have to work so hard. That required a lot of air in the suit since we wore so much lead… like 120 Lbs. plus the 50 Lb. hat.

My next dry dives were in early Poseidon Unisuits. The exhaust valve was manual and the suits fit like garbage bags so controlling the bubble required a lot of attention… pretty much sucked but there weren’t any better options in the Fjords of Norway for untethered divers in those days.

My trim… was a little shaky on my first Unisuit dives. One of the long-time Norwegian Unisuit divers tried to show me the ropes but I kept relating it back to deep sea gear, my only previous dry experience. One day, while I was obviously obsessing over the suit, this guy executes a slow-motion limbs-stretched cartwheel on the bottom. I could watch a very small bubble of air travel up and back each limb until he was upright staring me in the eyes. That was my light bulb moment. I probably took 5 Kg of lead off my belt after that and started to enjoy the dive again.

Akimbo:

…this guy executes a slow-motion limbs-stretched cartwheel on the bottom. ...

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A friend just E-mailed and basically asked “how the *#!& can you do that?”

He had a 2Kg/4.4 Lb maul in his hand. Maul in right hand stretched horizontal, right leg vertical standing on the bottom, left leg near horizontal, left arm near vertical. Start the roll and pass the maul from right to left, sort of hand-walking over the bottom. Start to raise the left hand with the maul to your leg to complete the roll. OK, there was a little bending of limbs, but surprisingly little fin assist. Great demo really. Would make a great training video, especially in a trilam suit where you can see the suit compression and bubble movement even easier.