Wikipedia article on "Doing It Right"

[lamont]

Meh, as further evidence that this is a troll, the Dan Orr citation supporting the claim that the BCD floats the diver better actually says this:

As part of your assessment, attempt to determine the style of BCD the diver is wearing and whether it is completely inflated. Is she having trouble breathing? Remember that a fully inflated jacket-style BCD may constrict the chest, making it hard to breathe. Is she struggling to keep her face out of the water? A fully inflated back-inflation-style BCD can force a diver's face toward the water. If the diver isn't used to wearing a back-mounted buoyancy compensator or wings, she may not understand why she can't keep her face clear of the water.

Which is basically what I said -- a. there's a trade off in the weaknesses between the two styles b. both types of failures largely come from inexperience.

 

[rlynch]

Thanks Lamont - I was going to work on the DIR equipment section (with pictures I'll take) before moving to the history & controversy section. reasoning is to establish the correct equipment list then use that for further edits to the areas which seem to generate the most controversy in the article amongst the editors.
Adding a snorkel to the equipment section along with possible uses and procedures would help the case in sections 5, 6, & 7.
Are there any studies related to nitrogen build up during snorkel use that you are aware of?

 

[danvolker]

Thanks Lamont - I was going to work on the DIR equipment section (with pictures I'll take) before moving to the history & controversy section. reasoning is to establish the correct equipment list then use that for further edits to the areas which seem to generate the most controversy in the article amongst the editors.
Adding a snorkel to the equipment section along with possible uses and procedures would help the case in sections 5, 6, & 7.
Are there any studies related to nitrogen build up during snorkel use that you are aware of?

The snorkel will not create new nitrogen issues, it will continue offgassing. Because the use of a snorkel is rarely taught, it is hardly useful gear for many divers, who really have no freediving or snorkeling abilities at all. For a scuba diver that is also a freediver, the snorkel is a spectacular tool should the diver come up far from the boat, or to find no boat at all. DIR divers often have thigh pockets, which are an excellent place to keep the snorkel until needed.

 

[cascas]

DIR divers often have thigh pockets, which are an excellent place to keep the snorkel until needed.

Pockets they rarely used for storing a snorkel. The DIR divers I know seldom even own a snorkel. A DIR diver plans his or her gas in such a way that when they surface away from the boat ( if at all) they can just breath from their tanks while swimming. Or they swim on their back. I personally only carry a snorkel in my pocket when teaching PADI courses just because the standards require that I do.

 

[danvolker]

Pockets they rarely used for storing a snorkel. The DIR divers I know seldom even own a snorkel. A DIR diver plans his or her gas in such a way that when they surface away from the boat ( if at all) they can just breath from their tanks while swimming. Or they swim on their back. I personally only carry a snorkel in my pocket when teaching PADI courses just because the standards require that I do.

This depends on where you dive of course.... I do not believe I have ever needed a snorkel after a dive off Palm Beach from the 90's on....
Prior to the nineties I needed one once from a shore dive in the inlet in rough seas, when the outgoing tide made the snorkel kind of necessary at dive end.
For normal use, it would be more like having a Halcyon Diver's Life Raft..for when the boat is GONE when you surface..they are cheap, and good insurance. While I am also a freediver, I do NOT typically carry a snorkel with me on dives off of Palm Beach, as the shore is only 2 to 3 miles away on most dives, and in 30 years I have only been left by a boat one time (in maybe 10,000 dives or something ridiculous)..
However, for a diver concerned about coming up far from a dive boat, they are awesome....it all depends on how much of a threat this is.

 

[lamont]

Thanks Lamont - I was going to work on the DIR equipment section (with pictures I'll take) before moving to the history & controversy section. reasoning is to establish the correct equipment list then use that for further edits to the areas which seem to generate the most controversy in the article amongst the editors.
Adding a snorkel to the equipment section along with possible uses and procedures would help the case in sections 5, 6, & 7.
Are there any studies related to nitrogen build up during snorkel use that you are aware of?

It isn't nitrogen build up during snorkel use that is the issue. The problem is the bubble shower you get from normally surfacing on a dive. If you then bounce down you compress those bubbles due to boyle's law and that causes their radius to decrease and they can shunt through the lungs then when you surface they can get stuck in capillaries. Normally the lung acts as a bubble filter to protect you from that and you are bypassing it by crushing the bubbles and letting them through.

DIR Reference: Why We Do Not Bounce Dive After Diving in the WKPP | Global Underwater Explorers

See the last sentence that freediving should be done before diving, not after diving.

Another reference: Can Freediving Cause DCS?

There's more here:

Alert Diver | Could Breath-Hold Diving after Scuba Cause Decompression Sickness?

Again there is "controversy" here since the medical experts tend towards emphasizing lack of scientific evidence:

"Again, though, there is no evidence of these factors causing injury. Studying a relatively rare event like DCS is difficult; studying a second rare event on top of the first is much more difficult."

The DIR answer given by George in that article is that they believe the WKPP has seen this, and that there's no need to bounce dive / free dive after diving, so there's no need to run the risk.

 

[rlynch]

lamont in this example it would imply that you are not simply transiting the surface (on the surface) but diving below the water on a breath hold. which i fully agree that would be considered a bounce dive situation.
My senario i was thinking about was simply swimiming 500 yrds from the shore to a site on snorkel, diving and then using a snorkle to transit the surface to the shore and any nitrogen build up that would cause. Seems to be no different than swiming without a snorkel in this case and would not be a bounce dive senario.

 

[TSandM]

There is no nitrogen buildup from snorkel use. There CAN be CO2 retention, especially if you are exerting. In the majority of cases, GUE divers do not use snorkels. They can cause problems with deployment of the long hose. A stowable snorkel might be fun if you need to do a surface swim someplace where there is interesting stuff to be seen in the water, but in general, we swim on our backs and eschew the snorkel altogether.

 

[Slamfire]

I would expand the comment to include divers beyond GUE or UTD. Around here lots of divers, particularly the experienced ones, don't carry snorkels. There is just no compelling reason to carry it and it does get in the way. Most people just swim on their backs or if they want to sight see from the surface, hold your breath or breath your reg. Divers that use BP/W quickly figure out that the danger of having a wing "unrecoverably force" your face under water is largely overstated. I know about this alleged "weakness" of BP/W, but I've never seen or heard of it happening to anybody in real life. It's like Lamont says, I do believe there is a higher likelihood of having an overtight cummerbund squeeze the breathing out of you, than a BP/W forcing your face down.

And unless you're very familiar with the underwater scenery of a particular site, you still have to bring up your head frequently to get your bearings and adjust course. I remember an occasion when I was baby sitting a pair of newbie divers, mom and son, equipped with snorkels. The 3 of us swam about 75 yards from the shore to a common site. There was a plankton bloom and visibility near the surface was null. When the mom saw this horrible vis, she said she was not going to dive, but that her son and I should go on ahead. I told her I would swim back to shore with her, but she declined insisting that we start our dive. She put on her mask and snorkel and started going back, or so she thought. I told the son I was not descending until I saw her getting safely into the shore. After she started turning into a second tight circle without ever raising her head to check directions, I told the son that the both of us are going back to make sure his mom got back to shore.

She would have been much better off without a snorkel. She had a jacket BC. She had a full tank. There was nothing to see except mucky plankton. And yet she's following her training blindly (literally) in totally inadequate circumstances because her training told her she should use a snorkel in situations like this. After experiencing incidents like this most newbie divers just wisen up and quit carrying a snorkel.

 

[boulderjohn]

Divers that use BP/W quickly figure out that the danger of having a wing "unrecoverably force" your face under water is largely overstated.

I had been diving for 4-5 years when I first heard the same thing about back inflate BCDs. It was a real surprise to me, since I have never dived anything else since my certification and hadn't noticed anything of the kind. When I started with a BP/W, I didn't notice anything of the kind, either.

I think that what happens is that people who start off with jacket BCDs get used to a certain body position while floating upright on the surface, and if they switch to either a back inflate or a BP/W, they find that their accustomed body position does not keep them upright. Once they learn to adopt a different body lean while upright on the surface, they don't even notice it any more.

Since we obviously do not normally spend a lot of time upright on the surface, it shouldn't be much an issue anyway.