100m dive

[Germie]

First about the bottomgas in a twin12: that depends on the consumption rate of the diver and the diveplan. I can do 17 minutes of bottomtime at 110m and still have a 100 bar left when I surface. So with students I plan mostly 15 minutes at 100m. That is mostly doable.
For a bounce it is doable. But I won't go in the tunnel at Dotty from 100-106m depth, as it is still overhead and oc you don't have any time to fix something at such depths.
If it is a bounce, a PO2 of 1.4 is ok. In warm waters I also do it. In cold waters I prefer to stay at 1.3 if I do bottomtime. To lower this to 1.0 or so makes the deco too long. END can be for me personally till 45m. But a 12/60 or 12/65 is for most people perfect and fits within the END limits of agency standards.
As travelgas I prefer a 21/35 and switch around 57m. Can be 54 or such a thing.
Then I personally move over a 40% oxygen, with some helium, so a 40/15. Why? Can be switched at 30m. Last gas ean80 or 100%. It is not the cns, but the gasreserve that makes you to choose or waves. I don't see ean80 as a stroke gas. On long oc deco's, it can be an advantage not to do airbreaks.
I dive 40/80 buhlmann.
But TS, have you done a full trimix course? Was a 100m dive not discussed? What was your deepest dive till now?

 

[kensuf]

In short it refers to unsafe divers and practices, see below

"The term *stroke* was coined by Parker Turner, the original project director of the WKPP. Parker, much like Irvine, had a no-nonsense approach to diving and running the WKPP. Parker had his rules as to the team and one either followed them or they weren't on the team. It was as plain and simple as that. But what Parker found over the years that there were so many people trying to get on the team without the willingness to put in the requisite work. Instead they would come up to Parker and tell him how they had done this dive or that dive, blah, blah, blah and Parker said that he was sick of these guys *stroking* him to get on the team.. That's the evolution of the word.It has since been expanded to include diver's that approach diving with an unsafe and/or cavalier attitude towards diving.."

The responding party did not answer your question, just plain negative personal attack IMO. Calling someone or their comments a stoke is in direct infringement of this board rues. IMO the poster attacked you describing you as an unsafe diver without any reasoning or explanations.

"You're stupid"

"That's stupid"

One is a personal attack, one isn't.

 

[Superlyte27]

Lighten up. No one was attacking anyone. Certainly not Kensuf. If I had said it, I’m sure the entire mod team would be discussing it right now to see if a ban was in order, but when have you seen Ken attack anyone.

You guys really need to learn how to take some playful ribbing. Friggin Swowflakes....


LOL LOL LOL... I’m just kidding mod team. You can delete the Friggin Snowflakes if you want. Seriously, just playing.

 

[ajduplessis]

"You're stupid"

"That's stupid"

One is a personal attack, one isn't.

No stupid is responding with stroke crap comments without even trying to answer a basic question.

But then again I did not expect anything else.

 

[RainPilot]

OK, I'll bite.

I'm not anywhere near doing 100m dives yet, my cert is only 50m and 30 min deco. I am also only allowed one deco gas, but it can be anything I choose.

On my (admittedly small) dives, I have to juggle deco obligations with gas requirements (bottom and deco) and work a plan from there. I do get standard gases, I am a fan for a variety of reasons, but not married to them especially if my team for the dive is on best mix.

My process is as follows:

1. Plug depth and desired BT into software, using standard gases.
2. Look at the gas required and deco time for the dive to get a first approximation.
3. Adjust the bottom gas to best mix and see the changes to get an idea of how useful it would be to blend.
4. Adjust from 50 to 100 for deco gas to see amount of gas required vs reduction in deco.
5. Adjust BT and deco gas to cover any "gas gaps"

Now in step 5, I am often going to 50 percent because it gets me on deco gas quicker in case of back gas failure and for the dives I am doing the deco difference is 2-3 minutes. However, if I found that 80% covered the gas gap nicely and had an acceptable deco penalty vs 100%, why would I be "stroke-y" to use it?

I know that a lot of people have advocated 80 as being "safer" because its more forgiving at 6m but that seems like admitting that you can't hold a stop. If my reasons go about gas carried vs deco incurred, I'm not sure how thats different from the method used to determine all the intermediate deco gases like 30/30 or 25/25 or whatever else may be needed.

I do ensure that there is a good supply of 100 on the boat (usually 2 AL80).

I don't know what I don't know so if someone could point out the flaws in my reasoning (outside of the standard gas argument) I would be grateful.

 

[Beau640]

you're using 50% instead of 100% for dives sub 150 feet? Stroke crap



I like 100% for a variety of reasons. For sub 150 feet, needing to jump onto deco gas quicker because of loss of back gas shouldn't be an issue. #1 the chances of literally losing all back gas should be almost impossible with modern manifolds #2 using the concept of minimum gas your teammate should have enough to get both you and them to your deco gas. 100% is such a nicer gas than 50%. Best partial pressure gradient, opens the oxygen window, and as Ken has said above is the first step in treatment of DCS.

I'll leave it to someone else to talk more about the 80%.

 

[Steve_C]

Nah

Most people (myself included) will interpret "You're stupid" and "that's stupid" the same way even though they are technically saying different things at the surface. Uneducated people say things that are incorrect. Stupid people say stupid things.

 

[PfcAJ]

you're using 50% instead of 100% for dives sub 150 feet? Stroke crap



I like 100% for a variety of reasons. For sub 150 feet, needing to jump onto deco gas quicker because of loss of back gas shouldn't be an issue. #1 the chances of literally losing all back gas should be almost impossible with modern manifolds #2 using the concept of minimum gas your teammate should have enough to get both you and them to your deco gas. 100% is such a nicer gas than 50%. Best partial pressure gradient, opens the oxygen window, and as Ken has said above is the first step in treatment of DCS.

I'll leave it to someone else to talk more about the 80%.

100% only on 150' dives dramatically increases your min gas volume.

 

[Beau640]

That’s true since your bottle is at 20ft, but I still don’t like the idea of having no O2 available at all for the dive. “Dramatically increase” is relative because for sub 150 and sub 30 minutes you don’t really have significantly long stops before 20 feet. The MG really wouldn’t be that much different between the two.

If you’re doing long ass dives with long ass deco you probably would need both bottles anyways.

 

[PfcAJ]

That’s true since your bottle is at 20ft, but I still don’t like the idea of having no O2 available at all for the dive. “Dramatically increase” is relative because for sub 150 and sub 30 minutes you don’t really have significantly long stops before 20 feet. The MG really wouldn’t be that much different between the two.

If you’re doing long ass dives with long ass deco you probably would need both bottles anyways.

Gf 60/85, 30mins at 150, 21/35 bottom gas and 100% for deco shows 19mins of stops before you get to 20’. That’s not insignificant.