How do you descend?

[fisherdvm]

Head first or feet first? Does it matter if it is drysuit or wetsuit?

I usually release a very small of air from my BC until my eyes are under water, then I flip my head down, and swim head first while clearing my ears with a hand on my nose. I add a little air slowly as I become more positive with increasing depth to slow my descent.

I will start drysuit class in 2 weeks, and I am guessing that head first descent is no longer effective because of the need to keep your shoulder high??

 

[spectrum]

Horizontal all the way.

I pull the back dump and free fall. I can watch for the bottom and scan for my buddy. The prone position also slows my fall so I can easily add BC air for suit compression while equalizing frequently. I also think that (for me) it gets me in a better posture for equalizing my ears, with my neck somewhat extended.

With the weight of a full tank on board you really should not require gymnastics to get down at the onset. Take a deep breath while dumping air then make a deep extended exhale to get the ball rolling, or the diver falling so to speak.

You can still go down feet last with a drysuit. You should have pretty well purged your suit of air and whatever is in there will start to compress as soon as you start your descent so you should not immediately find your self in a buoyant boot situation.

The trouble can come when you are depth with air in your suit to avoid squeeze. If you rise in the water column allowing this air to expand and not vent due to posture or a closed valve you will have a big bubble. If while carrying a big bubble you put your feet high and allow an ascent to commence then Boyle's law will take you up, up & away.

Pete

 

[fisherdvm]

Come to think about it, I am probably more or less horizontal. To keep above the group that are already down at the bottom, I'd swim against the current so not to drift too far from them. I guess if I had a drysuit, horizontal is probably the way to go with the shoulder higher than the feet, right?

 

[spectrum]

Come to think about it, I am probably more or less horizontal. To keep above the group that are already down at the bottom, I'd swim against the current so not to drift too far from them. I guess if I had a drysuit, horizontal is probably the way to go with the shoulder higher than the feet, right?

You have the right idea but stay horizontal. You will become aware of the bubble very soon and when it needs help escaping just roll a bit to put the exhaust at the high point and let it work. If things are not responding as fast as you'd like you can aways go slightly heads up to provide motivation for the air. Remember that it vents MUCH slower than a BC dump valve so you want to avoid abrupt ascents.

Pete

 

[JAMIE MCG]

Spectrum, I too will be trying a dry suit out in three weeks. when I weight myself its just enough not to fight at the safety stop without a line. for instances in freshwater 3mm 4lbs but i cant just dump my air and decend I have to swim to the bottom, and usually I dont had but a shot of air in my BC once at the bottom. So from reading this I would want to be a little over weighted maybe 2 more lbs so I could decend horizintal?

 

[spectrum]

Spectrum, I too will be trying a dry suit out in three weeks. when I weight myself its just enough not to fight at the safety stop without a line. for instances in freshwater 3mm 4lbs but i cant just dump my air and decend I have to swim to the bottom, and usually I dont had but a shot of air in my BC once at the bottom. So from reading this I would want to be a little over weighted maybe 2 more lbs so I could decend horizintal?

If you can hang at your safety stop without flight then you are just about there. You should be able to complete your ascent slowly as well. Some drysuit divers will carry a few extra pounds in case they don't vent perfectly at some point.

It sounds like you are not wearing a lot of insulation for diving in Georgia so that moderates a lot of things. Next time you get in the water bob plumb and let the surrounding water squeeze the air from your suit through the opened exhaust valve. If you are carrying enough weight to hold a stop with an near empty cylinder then you should go down easily with a full tank and empty suit when you vent your BC.

Pete

 

[fisherdvm]

Jamie, when I am not properly weighted, I will find myself drifting up at about 1000 psi or less. What I do at that point, is I exhale and swim down to the nearest small rock. Then I just swim along until I find small enough rocks that I can put into my BC pocket. Then I drop the larger rock that I've been carrying.

I've not done it, but certainly, when you surface, you can weight the rocks in your BC pocket, and it will give you what you need for the next dive.

I find that with a dry wetsuit, and a dry BC, even when you are properly weighted, you might be slightly positive at the surface. That's when flipping and swimming head first will get you down. Once the water percolate and permeate every air pockets in your BC, your wetsuit, and after you've burped and flatulated.... Then you are again positvely buoyant. Of course, I don't know if this can be done with a drysuit.

I've seen some divers who bore larger holes on their BC back plate to let the air escape faster. But it is not unusual to find it hard to descend even if you are wearing the right amount of weight (6 lbs above neutral buoyancy with a full tank - plus or minus depending on your tank size).

 

[cummings66]

First during a descent it's not something to think about in a drysuit, you can go down headfirst if needed. The air is compressing remember, so any floaty feet get better as you go deeper and thus it's not a problem. Keep in mind you get negative not positive as you go deeper so what you're doing is essentially identical to a wetsuit when you go down except at some point you're going to use the drysuit inflator to alleviate squeeze instead of the BC inflator. If you're like most you'll use both, but you'll quickly discover you need to use the drysuit inflator to keep a comfortable feeling in the suit.

As to weighting, trying to get a drysuit trimmed perfectly at the safety stop is not really going to work well for new drysuit divers, you'll probably find it awkward trying to stay down if you do. The drysuit is also more comfortable with a bit more weight since you can then keep a bit more air in the suit keeping you warmer.

To be honest I'm of the school that you need to be able to stay under water at 5 feet with an empty tank because in our lakes there's often boats and jet-ski's that circle your bubbles. If you have no control over it and can only be neutral at 15 feet when you get to 5 you're going to rise right into the bottom of one of them someday. I do not think neutral at safety is safe under all conditions.

Also keep in mind that keeping your should high is only needed when you want to vent, you're not venting the entire dive and thus your shoulder does not need to be high all the time.

 

[Jim Baldwin]

Head first or feet first? Does it matter if it is drysuit or wetsuit?

I usually release a very small of air from my BC until my eyes are under water, then I flip my head down, and swim head first while clearing my ears with a hand on my nose. I add a little air slowly as I become more positive with increasing depth to slow my descent.

I will start drysuit class in 2 weeks, and I am guessing that head first descent is no longer effective because of the need to keep your shoulder high??

I like to descend horizontial as well. With new divers it is often difficulty to get them to be still and relax so I work with them on feet first. I get them to cross their legs. This stop the excess finning. Dump any air in BCD look up and then deep exhale. Shallow breath and deep exhale. This usually gets them started and they realize they don't need 30lbs to actually sink if they will relax and quit moving.

Once we get rid of the excess weight I work on getting them horizontal. I have found head down descents the most difficult and if a person's tubes are going to lock up it will be trying to do a head down descent. Plus you have to fight the air that is still trapped in your lungs. Just doesn't work for me.

 

[scubafool]

I think that cummings66 brings up a good point. I have seen it said many times to weight yourself neutral with 500psi at 15'. I believe that you should be neutral at the surface with an almost empty tank, allowing you, if needed, to descend once again.

As to the original question, I always initiate descents in the horizontal. There are some situations that will cause me to go head down, though. Several of the springs here in Florida have a very vigorous outflow, and going head down allows you to minimize the profile that is exposed to flow, making descents easier.