what's up with this dir stuff.

[Thalassamania]

Yes, there are some mistakes in there, but the point of that section was "dive a balanced rig." Neoprene drysuits are suboptimal because they require additional weight (compared to a shell suit), thus more effort is required for swimming, and they make it difficult for a rig to be balanced since they compress at depth. My understanding was the military drysuits were either TLS350s or CF200s....CF200 is in the "shell suit" category because it has very little change in buoyancy. By "neoprene" they mean those thick uncompressed 7mm neoprene suits.

When diving a 7mil uncompressed neoprene suit, the suit material is part of your insulation, as it compresses you add air to compensate for that compression, just as you would add air to compensate for the compression of any gas based (and aren’t the all) insulation. If you're smart enough to have gotten one made of GN231N, then it compresses less than does other gas-based insulations. This is nothing more than urban myth.

On the other hand, the big plus to DIR is standardization. My divers have always dove the way I taught/told them to. I’ve always stayed open to changes and innovations, but have never moved rapidly to incorporate them. When you dive a “team approach,” a marginally non-optimum, but standardized, solution to an issue is in most cases preferable to an “everybody do their own thing” approach.

The problem with DIR is that when a new idea or suggestion comes up some folks seem to get disoriented and run about like a chicken with its head cut off. Permit me to harken back to our recent discussion of the length of BP/W hoses that got into my suggestion that a ½ by 1 inch piece of neoprene glued in the nose pocket of your mask could help, which was met by cries of derision until I posted Peter’s note to me that said is was OK and the DIR dives should be thinking divers. There’s not been a word in response here or on DIREXPLORERS since I put his post up. I would have no hesitation at taking a group of thinking DIR divers out to do complex research tasks just as I do divers trained to AAUS standards, but I’d have to screen carefully to be damn sure that the unimaginative, auto-authoritarians, were left behind, because IMHO, they’re more dangerous than a PADI/NAUI/SSI/SDI/XYZ two day wonder (who at least knows that he or she don’t know poo).

 

[JeffG]

Quick, INNOCENT, NON-JUDGEMENTAL question from someone who doesn't know much about DIR... :huh:

Well 2 Questions:

1) Is GUE the same thing as DIR??

2) If you don't use neoprene, what do you use? Drysuits only?

Thank you in advance for not shooting my head off for asking this question.

DIR is a set of diving policies and procedures supported by a specific equipment configuration.

GUE is a training agency that teaches the DIR method.


Short answer for #2: They do not recommend thick neoprene for colder water. A shell type drysuit is a better choice for a variety of reasons.

 

[markfm]

Maybe. That's a pretty old article. ...

Thanks for the info.
Streamlined, balanced, things fit -- I doubt anyone could disagree with that.
(I really don't have anything against DIR, was curious about that one reference URL because of it being over-the-top.)

Personally, I like my Northern Diver Divemaster dry suit -- seems to take abuse better than a lot of other suits I've seen people using.

 

[JeffG]

When diving a 7mil uncompressed neoprene suit, the suit material is part of your insulation, as it compresses you add air to compensate for that compression, just as you would add air to compensate for the compression of any gas based (and aren’t the all) insulation. If you're smart enough to have gotten one made of GN231N, then it compresses less than does other gas-based insulations. This is nothing more than urban myth.

No its not.

Either your suit hold the gas that insulates you or your undergarments do.

In your example of using both is the worst way to dive a drysuit. You can never re-gain the buoyancy lost in the neoprene except in a bubble in your BCD or your drysuit.

 

[Thalassamania]

No its not.

Either your suit hold the gas that insulates you or your undergarments do.

In your example of using both is the worst way to dive a drysuit. You can never re-gain the buoyancy lost in the neoprene except in a bubble in your BCD or your drysuit.

View if for a minute, if you would, from the nylon covering inwards.

Assume the nylon is a "shell suit" bonded to your foamed neoprene undergarment (under which you may or may not be wearing another insulating garment). As you descend that which is inside the "shell" will be compressed, be it gas or gas trapped in neoprene (the gas trapped in G231N will actually compress less).

Yes you wind up with a small quantity of "free gas" in a foam suit, but not substantially more, in my experience, than you get in a membrane suit that is crushed against your chest and the compensating air shifted to across your back and legs. In either case you use that "extra" gas to maintain trim and position by shifting small amounts between the three "pockets."

I can’t put my hand right on the study but I will keep looking and post it when I do, that showed (or at least suggested) that foamed suits were warmer because of the compression of the insulation and trapped gas on the diver’s ventral surface.

 

[Soggy]

When diving a 7mil uncompressed neoprene suit, the suit material is part of your insulation, as it compresses you add air to compensate for that compression, just as you would add air to compensate for the compression of any gas based (and aren’t the all) insulation. If you're smart enough to have gotten one made of GN231N, then it compresses less than does other gas-based insulations. This is nothing more than urban myth.

We'll have to disagree on that one. If you add enough gas to the suit to compensate for the loss of buoyancy in the neoprene, you're floating in a big bubble which is also not ideal. You may not mind it, but it's far less work to dive without that big bubble floating around and keep a consistent volume of gas in your suit throughout the dive.

they’re more dangerous than a PADI/NAUI/SSI/SDI/XYZ two day wonder (who at least knows that he or she don’t know poo).

My experience is that XYZ divers tend to think they know far more than they do. By no one wants to dive with the type of diver you are describing. Someone who has been exposed to a DIR-F class usually comes out understanding that one should question everything and think the problems through.

 

[cmalinowski]

Quick, INNOCENT, NON-JUDGEMENTAL question from someone who doesn't know much about DIR... :huh:

Well 2 Questions:

1) Is GUE the same thing as DIR??
...

Need a new bucket oh popcorn for this one...

My answer: No. But then again, I'm a GUE diver

 

[Soggy]

Yes you wind up with a small quantity of "free gas" in a foam suit, but not substantially more, in my experience, than you get in a membrane suit that is crushed against your chest and the compensating air shifted to across your back and legs. In either case you use that "extra" gas to maintain trim and position by shifting small amounts between the three "pockets."

The deeper you go, the more free gas you get. That is not ideal. That is why neoprene suits are not considered DIR. While it may be your opinion that it is "not substantially more," it is indeed more and is not an ideal way to dive a drysuit. That it is an acceptable amount to you personally is irrelevant to the point.

I can’t put my hand right on the study but I will keep looking and post it when I do, that showed (or at least suggested) that foamed suits were warmer because of the compression of the insulation and trapped gas on the diver’s ventral surface.

Yes, given the same undergarment, a neoprene suit is warmer. That is certainly a fact. However, by using a good undergarment, that effect can be counterbalanced. The fact that my 155 lb, 6' tall body can do 60-90 minute dives in water in the mid 30s is proof positive of that. The undergarment is a better place to put your insulation because it does not change its buoyancy with depth.

For the record, the Flying Spaghetti Monster would never dive a neoprene drysuit.

 

[Thalassamania]

We'll have to disagree on that one. If you add enough gas to the suit to compensate for the loss of buoyancy in the neoprene, you're floating in a big bubble which is also not ideal. You may not mind it, but it's far less work to dive without that big bubble floating around and keep a consistent volume of gas in your suit throughout the dive.

I know how hard it is to clearly consider long held dogmas, I used to share this one, but I've been persuaded to change my view.

Of course you keep a constant volume in your suit. Otherwise you can't remain neutral. When I dive my Viking or DUI and say horizontal, air gets shifted to my shoulders and legs away from my ventral surface in almost the exact same way and quantity that it does when I dive my Polaris. The Swedish paper I'm looking for a the moment documents this. It ges on to show that a foamed suit is warmer because more insulation remains on the ventral surface than with a shell, membrane or crushed suit.

 

[JeffG]

I know how hard it is to clearly consider long held dogmas, I used to share this one, but I've been persuaded to change my view.

and people say DIR divers are insulting.

Of course you keep a constant volume in your suit. Otherwise you can't remain neutral. When I dive my Viking or DUI and say horizontal, air gets shifted to my shoulders and legs away from my ventral surface in almost the exact same way and quantity that it does when I dive my Polaris. The Swedish paper I'm looking for a the moment documents this. It ges on to show that a foamed suit is warmer because more insulation remains on the ventral surface than with a shell, membrane or crushed suit.

If the gas within the neoprene is compressed and compensated for via a bubble in your shoulders. You have lost your thermal protection.

Have you dove a drysuit?

Because your answers say that you haven't and quoting some Swedish paper say your just diving from your desk.