deco myths

[EFX]

He also uses the phrase "deco dive" to mean one with a mandatory decompression stop, in contrast to a "no-stop" dive. (See for example, Myth #2.) In other words, he uses it both ways. It's clear from context when he uses "decompression" as a synonym for off-gasing.

And that's the problem. Some people don't pick up context. I've said this before in another thread that the term NDL is the problem because it is misleading. It implies, if you take the term literally, that you will not decompress if you stay within the limit. I offered the term NSL "No Stop Limit". Although more accurate the term isn't complete. It should be NMSL for "No Mandatory Stop Limit". This eliminates the confusion over safety stops which are not mandatory stops.

For recreational divers the problem with deco stops besides trying to hold a fixed depth in the water is the additional gas planning involved. You have to make sure you have enough gas to complete the mandatory deco stops. Recreational divers generally do not get this training.

 

[Lorenzoid]

GUE uses the term "minimum deco" to refer to what some refer to as "no deco."

 

[beldridg]

NB: I haven't watched the video but I'm pretty sure I can interpret the content.

I think that one thing to keep in mind is that there is no black-and-white division between "no-deco" and "mandatory deco" dives -- especially in the world of dive computers and multi-level diving.

For example, I think the default Shearwater recreational mode gradient factor is 40/85? I generally run 50/80 which will change my NDL on the same exact profile as somebody running the default. Other computers with proprietary algorithms have different conservative factor settings. The "no-deco" limit will be determined by those settings.

The one thing I learned a long time ago (I think from J. Chatterton) is that "nobody ever got bent from doing too much decompression time" which can also be IMHO expanded to "safety stop time."

When I was in Bikini recently I would add at least 3-5 minutes on top of the 45-60 minute deco time. I would generally run my SurfGF down below 70. Same thing with my recent expedition to visit the USS Moray.

My advice to all divers is that there is no glory in surfacing early and extra time on deco or safety stops certainly won't hurt (assuming you have the gas to do so).

- brett

 

[LI-er]

He also uses the phrase "deco dive" to mean one with a mandatory decompression stop, in contrast to a "no-stop" dive. (See for example, Myth #2.) In other words, he uses it both ways. It's clear from context when he uses "decompression" as a synonym for off-gasing.

That's not what I got out of the video. He says, in Myth#2 at about the 8 minute park, as per the chart he provides, that a "no-stop" dive is a recreational dive with no required stops. In contrast to a "deco dive" which has mandatory decompression stops.

Seems fairly straightforward to me!

 

[Cthippo]

When I was in Bikini recently I would add at least 3-5 minutes on top of the 45-60 minute deco time. I would generally run my SurfGF down below 70. Same thing with my recent expedition to visit the USS Moray.

How do you keep from going crazy on a 60 minute deco stop? Sitting at 20 feet doing nothing for 3 minutes is hard enough for me!

 

[LI-er]

How do you keep from going crazy on a 60 minute deco stop? Sitting at 20 feet doing nothing for 3 minutes is hard enough for me!

I always thought the same. One of the main reasons I never pursued technical diving.

Would rather make a couple of shorter dives separated by a warm, sunny surface interval while eating snacks and drinking ice cold water than doing one longer dive and then hanging on a line trying to stay awake for an hour or more.

 

[inquis]

He also uses the phrase "deco dive" to mean one with a mandatory decompression stop, in contrast to a "no-stop" dive.

That's not what I got out of the video. [...] In contrast to a "deco dive" which has mandatory decompression stops.

Are we not saying the same thing?

 

[Moerae]

How do you keep from going crazy on a 60 minute deco stop? Sitting at 20 feet doing nothing for 3 minutes is hard enough for me!

It's pretty zen. I just relax and zone out a bit. Occasionally while drifting you'll see some neat terrain or animal life, but usually it's mostly just blue nothing. When you're on a mooring line you can people watch a bit as recreational divers go up and down, and you'll see wildlife usually.

Ultimately, no, it's not much fun. But we're all adults capable of being bored for an hour. The idea is that it's "worth it" to do deeper/longer dives.

Would rather make a couple of shorter dives

Eventually, when you want to start going far into overheads, or hitting wrecks at certain depths, you don't really have the option of multiple shorter dives. For me that the general reason I'll do long deco. I'm happy to do multiple dives with light deco if I'm checking out a shallow wreck or not going to far into it, but sometimes when you want to see specific areas far inside deep wrecks, you just can't safely do it without a lot of deco.

 

[LI-er]

sometimes when you want to see specific areas far inside deep wrecks, you just can't safely do it without a lot of deco.

I understand there are limitations in recreational diving that tech divers are not subject to including what you posted and of course the ability to dive deeper reefs and wrecks. I'm just saying to me, the additional time spent on a hang, and the time, expense and additional gear is simply not worth the trouble.

 

[Moerae]

The "Every dive is a deco dive" argument is always weird to me. Everyone always fundamentally agrees on everything yet argues about random pedantic stuff.

There are interesting things to talk about with this topic. How NDL vs deco gets taught, how playing with GF can change an NDL dive to a deco dive. Like go have a conversation with a recreational diver who sets their computer to 90/90 and does "ndl dives" riding the line and ask if there isn't something worth thinking about with regard to how we teach "ndl" diving.