Advice for ascending

[Thrillhouse]

I've done about 14 dives now and my buddy and I are now comfortable down at 60 or so ft, our max as OW divers. We're going diving next weekend so I'd like to verify a few things about safe ascent, considering the fact that air expands and that I use a dry-suit.

While I'm sure our ascent will be fairly gradual (touch 60, slowly work our way up to around 20, safty-stop, then putter around that depth and above until air is around 400psi) I'd like advice to avoid shooting to the surface.

First of all, let me verify: all ascents should be done under physical power alone, rather than putting air into the BCD? I think this is pretty much a given, but I'ld like to verify. Also, I've had problems in the past with purging air in my drysuit, and as such I'm reluctant to put any in. What advice can you give me regarding keeping it comfy but at the same time not so inflated my legs kick up/I experience uncontrolled ascent because of the air in it? I dive with a BARE Next-Gen shell-suit.

Also, (I know it's discussed to death) I dove my last 2 dives without a snorkel and loved it. All shore-dives in non-choppy water, and the lack of a snorkel gave me one less thing to worry about snagging on something and opening my mask to flooding. Do you think it's cool to not have the snorkel? I like it a lot more.

 

[Thrillhouse]

Oops... Can someone please move this to beginner discussion?

 

[MikeFerrara]

I use buoyancy control for up and down movement, remaining horizontal. Assuming you're neutral already, just taking a breath or arching your shoulders back a bit (which raises you lungs a little) will get you positive enough to initiate your ascent. after that, vent as needed.

What makes you comfortable at 60 ft if you're still unsure of basic skills like ascending?

 

[DA Aquamaster]

One issue that can make it difficult to purge a suit is if there is just not much gas in it anyway, but you probably need to describe that in more detail if there is an issue with gas trapping somewhere in the suit.

You need enough gas in the suit to keep from getting squeezed and to loft the insulation properly, but more than that is a bad idea due to gas shifting, etc. With an adjustable valve you can set it so that gas over this point will vent more or less automatically. I will set the valve there and leave it until the end of the dive where I may close it a bit more if I am ascending vertically where more air tends to dump otherwise.

As long as your boots are not too large or the legs too long, getting air in the feet is recoverable and is something you should practice now and then. Even if things are a bit larger or long, ankle straps can keep your feet in the boots.

Ascent wise, I also use bouyancy while perhpas going a pound or two negative as I approach a deco or safety stop which normally results in just enough expansion to put me neutral at the stop. I think it helps to plan on stopping at 15-20 feet on the way up as the last 20-30 feet is where the most rapid gas expansion will occur and coming to a full stop at 15-20 esures you have things well in hand for a slow ascent to the surface.

Whether you use gas in both the BC and the suit for bouyancy control is an often argued subject but it is an issue that is easily resolved non issue. If you are properly weighted with a single tank of reasonable size (AL 80 etc) the amount of air carried in the suit to loft the insulation will be adequate to provide neutral bouyancy and as you use air and gain bouyancy a little snugger fit on the suit will keep things in hand - in essence you use the suit for bouyancy as the extra 5 lbs swing weight of the tank will not result in excessive gas in a properly fitting suit.

If you are over weighted due to having too much lead, a large single tank (120-130 etc), doubles, or stage and deco bottles, this will not be the case and you will want to stop adding air to the suit after the insulation is fully lofted and add anything else you need for neutral bouyancy to the BC or wing. This leaves you with two gas volumes to manage, but it is much easier than trying to manage a big gas bubble in the suit.

Some dry suit divers dive in a well squeezed condition feeling that an abusolute minimum of gas in a dry suit is desireable. In my opinon this is just uncomfortable and results in the suit being colder than it has to be. So in effect, if I do this it is for temperature control in conditions where the suit and insulation combination is too warm for the water temp (deco above a thermocline, etc).

 

[spectrum]

Thrillhouse,

It sounds like you are on the right track. Just to add a few tidbits to the above...

You do want to be ascending without adding air to your suit or BC but it's a little different than a wetsuit or neoprene drysuit. When you leave the bottom in a neoprene suit it will begin to rebound and the increasing buoyancy will provide upward lift. You will then vent BC air to compensate for the expansion of suit rubber and BC contents. Your laminate drysuit on the other hand will try to maintain the same differential and aside from trapped air not change as much. You should find that you are venting less from your BC since it is primarily that bubble that is growing.

On ascent you may at times need to pitch your body to be somewhat feet down head up to facilitate air escape. I feel this as a strain in my finning since my legs are fighting an increase in buoyancy in my feet and legs. It's a departure from the prone flat trim we strive for but it's the reality of bubble management,

Wearing the right undergarments is also important. They want to fit well and vent well. If you have the BARE garments with the vent grommets you know what I mean. You do not want a supple non porous shell that can suck up to the vent valve and plug it.

If you do not dive with the valve wide open you probably want to open it when leaving the bottom.

As for the snorkel you know the score, you know your sites and you know your dive plan. Make an intelligent choice. In open water I have never had a problem with my snorkel dislodging my mask.

Pete

 

[caseybird]

Halcyon makes gaiters that are very effective for keeping air out of your feet and lower legs. They wrap around your ankles and calves and prevent air from inflating your drysuit or boots. They need to be snug, not constricting. With gaiters, your feet will be much more secure in the boots and fins if you get your feet higher than your head. Like Spectrum, I keep my shoulders a little higher on ascents to keep the air in the drysuit moving towards the vent. Suits respond a lot slower than BC's, you have to keep a little ahead of them.

 

[Skookumchuck]

No need for a snorkel Thrillhouse, just count the number of divers at Whytecliff or even Porteau heading for the Nakaya actually using one. For accent turn your dump valve to its loosest setting,counterclockwise, and all you have to do is raise your arm.

 

[TSandM]

You're quite right not to initiate ascents by adding any air. If you are diving at neutral buoyancy, as you should be, all it takes to start up is to take a deep breath. (For those of us who are very small, and have small lung volumes, sometimes a surreptitious kick or two keeps us on track with larger buddies.)

Managing the ascent with a drysuit is all about anticipation. If you are shore diving, you know the topography of the slope you swam down. As you come back up, you can say to yourself, "Okay, I know this part gets shallower", and work on putting your shoulder in the right position for the drysuit to dump. If I get a little behind and start to feel light, I vent my wing (BC), because it will vent much faster than the suit. But proper anticipation can let me avoid doing that more than a few times on the way up.

If you are doing a direct ascent to the surface, as when you dive off a boat, it's a little trickier to know exactly how much you need to vent, and from where, to do a lovely, coordinated ascent. It takes practice, and when you start, you're likely to do some yo-yoing at your safety stop. We all (or at least most of us) went through it! I could hold my buoyancy perfectly up to about 4 fsw swimming upslope LONG before I could hold a 15 foot stop with plus or minus 3 foot accuracy.

Anyway, anticipation is the key -- Think about what you're doing, and what you're going to need, and stay ahead of the requirement to vent, and that should prevent any unscheduled excursions to the surface.

 

[1_T_Submariner]

Well you already have some great responses but I can't read and then not add something.

You may want to try a fold up snorkel in a pocket just incase you would need it.

Have you taken a Drysuit class? Wether formal or not. I took one after about 20 dives in a drysuit and found I still learned quite a bit good practice etc....

 

[Doc Intrepid]

Same as 1 T Submariner...

Another small detail is the exhaust valve - it turns. (righty tighty...etc.)

Ensure that for now you've opened it all the way. (turned to the left as far as it will go)

Don't close it while you're diving. Ensure your valve is fully opened.

(Some folks close it at the surface to inflate their suits at the surface a bit...)

Sounds like you've gotten great advice above...