Repetitive diving on CCR

[Okeanos]

A couple of comments..........

Clare - my SAC rate is like Chasey's, the same at 60m in the UK as it is at 20m in Thailand.

Fin - I totally agree, SAC rate after a CO2 hit is unmeasurable. I calculate at 40lpm for 1st bailout gas but I know people who have gone up to 200lpm, if that happened it ain't happening.

Chasey - When did you do your 110m dive for 30minutes? Is it actual or are we just talking in theory.

Re:- CO2 in the system, from what I've heard and spoken to people about it does vary. RMV will stay high for several minutes. After Mark E's experiment in Malta he said his vision went and took a couple of minutes to come back, his breathing took about 5 minutes before it started to slow down.

On the subject of Mark E's experiment he did say that he went back on the unit at 6m after he knew the scrubber was depleted. At 6m running as an O2 rebreather CO2 would be minimal and the PPCO2 also not too significant, his breathing remained normal at 6m and he finished off his deco on the unit.

[Mark Chase]

Originally Posted by SoggyFox

for better or worse?

If you struggle with your SAC on OC then your going to relax on a CCR and it will get worse.

SACS should be honest. Cheating by skip breathing or forcing uncomfortable breathing rates is no good at all for dive planning. This is hard because in diving admitting to a high SAC is akin to admitting you have BO

Planning for Bailout using the TDI platform your told to estimate on 40SAC. With my average planned of 14 thats a massive margin. If your average SAC is 25 then its not.

I never struggle with my SAC just flicking back over some of the dives i did early on in my diving the worst SAC I could find was 22 at Stony cove diving in a semi dry doing my AOW

Some of the single tank dives i did in the Maldives back in 2000 were drifts and I was doing sub 10 SACs on bottom gas. Most of my old single tank dives were between 12 and 15 SAC. My first ever trip on the Thistlegorm for example i did an SAC 10.3 on the first dive in slack conditions and penetrating the wreck the next two dives (the same day) were in quite a strong current and i clocked 13.1 and 13.7

There is no particular skill involved in this its just coincidentally what i do. It like reaching your valves you either do it easily or struggle with it all the time.

ATB

Mark

[Mark Chase]

Originally Posted by Okeanos

A couple of comments..........

Clare - my SAC rate is like Chasey's, the same at 60m in the UK as it is at 20m in Thailand.

Fin - I totally agree, SAC rate after a CO2 hit is unmeasurable. I calculate at 40lpm for 1st bailout gas but I know people who have gone up to 200lpm, if that happened it ain't happening.

Chasey - When did you do your 110m dive for 30minutes? Is it actual or are we just talking in theory.

Re:- CO2 in the system, from what I've heard and spoken to people about it does vary. RMV will stay high for several minutes. After Mark E's experiment in Malta he said his vision went and took a couple of minutes to come back, his breathing took about 5 minutes before it started to slow down.

On the subject of Mark E's experiment he did say that he went back on the unit at 6m after he knew the scrubber was depleted. At 6m running as an O2 rebreather CO2 would be minimal and the PPCO2 also not too significant, his breathing remained normal at 6m and he finished off his deco on the unit.

No theoretical my deepest was 105m but the bailout plan is pretty much the same.

I have been offered slots several deep UK dives 100m+ and turned them down. Not because of the depth which is instantly what people assume, but because the balance between the deco in green nothing ness and the quality of the dive is all wrong for me.

Andyp and i got the chance to do the Dead lite subs with Ron Mahony about three four years ago when we were on OC. I looked at the cost of the gas and the 15min bottom times and thought no dive on a sub was worth £13 a min

If I get the chance to do the Victoria before I am 50 id definitely do the bottom at 146 because you can stay on the wreck all the way up to 75m on the ascent which is just soooo cool apart from that the Britannic is the only deep dive on a wreck I would seriously consider.

The depth doesn't control my diving. It doesn't matter if i am at 50m or 90m the in water time will be a max of around 180ish mins. My longest dive was 216mins and i was going insane toward the end. The MP3 player is making a massive difference and i found the 180 and 195min runs we did in Malian head to be not so much of a problem.

I just sold my Classic Inspo after hanging on to it for the occasional monster dive. In the end i decided that the 110m limit on my KISS was adequate for my needs



ATB

Mark

[MixedUp]

Originally Posted by daveb0000

For instance would you dive to say 50m and then dive again later to 20m or would you dive deeper and still dive later. or would you keep the second dive very shallow say 10m on top of a reef.

What have you guys done ?

Typically when doing sea dives I would just do the one dive a day when going beyond 50 metres. But at NDAC I have done a 60 metre dive followed by a 50 metre dive a couple of hours later.

Steve

[Okeanos]

Originally Posted by Mark Chase

If I get the chance to do the Victoria before I am 50 id definitely do the bottom at 146 because you can stay on the wreck all the way up to 75m on the ascent which is just soooo cool

They've found the bell now, on the bottom at 156m. If you go inside you can get another 20m as the bow is buried in the sand.

I would love to dive it, but again for me it is a cost problem. Maybe one day.

[daveb0000]

Originally Posted by Steve Jones

Typically when doing sea dives I would just do the one dive a day when going beyond 50 metres. But at NDAC I have done a 60 metre dive followed by a 50 metre dive a couple of hours later.

Steve

when diving in the UK we would probably do exactly that Steve, just a case of when we go to Hurgarda we want to "make hay while the sun shines" so to speak.

Regards

Dave

[daveb0000]

Originally Posted by Mark Chase

They don't call me the "shot monitor" for no reason M8

I have dived to 102 on OC and I used these gases for travel gas and deco without issue. On more shallow diving i have back gas switched from 14/65 to 32% on dozens of dives without issue.

Have a word with Kevin Gurr. he still does an Air flush on diluent at 60m

As a result i don't think going from 13/65 to 21/35 to 36% to be any sort of problem AT ALL. Even the DIR boys and girls switch from 15/55 to 50%


The plan for 100 was 30mins not 35. The additional 5 is for the decent time.

Bailout plan is above on a 40SAC you need 150 bar out of a 10.

According to the hyperbola on massive SACs on C02 hits you can never carry enough gas. So whats the point in worrying about it?

I use a BOV and would bailout long before my SAC hit 30 for no reason. 110m is a zero work load dive for me. If I have to start working something is wrong and I am going up. If my SAC went over anything but relaxed for no reason Id go OC and abort. Screw dill flushes and semi closed which is just delaying the inevitable and building up even more C02, thats all crap IMHO. I carry the gas so i might as well use it.

If i bailed on to deep mix and it ran out before the gas switch all you can do is go back on loop semi closed till the next switch. With a flooded loop all you can do is switch and hit the accelerator

But your quite correct I don't know many divers who will buddy me on a 30min at 110m dive. Which is why I prefer not to do them. 20mins on a wreck is hardly worth the bother of getting down there. I have a personal preference of a max 3hour run time as well so its got to be damed special to keep me in the water for four hours. I plan a dive on run time. Wether its 50m or 90m the run time is 180mins ish if its a good wreck and 120mins if its OK to poor. Depth not relevent.

I much prefer diving in the 50-80m range and doing 40-60min on the bottom. Thats a proper exploration dive and not a glory dip to touch the wreck.

ATB

Mark

Mark

i think we have to keep things in context here before we start rubbishing the dives that other dives want to do and i quote

"Which is why I prefer not to do them. 20mins on a wreck is hardly worth the bother of getting down there."

also

"Thats a proper exploration dive and not a glory dip to touch the wreck."

Me and Ash have both been developing our diving over the years to get to the stage we are at now and this trip will help to develop that even further.
for us to go out and jump in and do 35mins to 110m basically would be bloody foolish, surely you would agree that these sort of dives need to be build up to over a period of time. 15 Min's this time maybe 20 Min's the next if all goes well and to plan.

on this trip we are happy with what we want to do, its all about gaining experience and knowledge. you never know one day we may be on the same boat. now there's a thought.

respectfully

Dave..

[Dr T]

anyone

a

[gobfish1]

[Mark Chase]

Originally Posted by daveb0000

Mark

i think we have to keep things in context here before we start rubbishing the dives that other dives want to do and i quote

"Which is why I prefer not to do them. 20mins on a wreck is hardly worth the bother of getting down there."

also

"Thats a proper exploration dive and not a glory dip to touch the wreck."

Me and Ash have both been developing our diving over the years to get to the stage we are at now and this trip will help to develop that even further.
for us to go out and jump in and do 35mins to 110m basically would be bloody foolish, surely you would agree that these sort of dives need to be build up to over a period of time. 15 Min's this time maybe 20 Min's the next if all goes well and to plan.

on this trip we are happy with what we want to do, its all about gaining experience and knowledge. you never know one day we may be on the same boat. now there's a thought.

respectfully

Dave..

I am not rubbishing any one doing build up dives

I am talking about where my diving is right now, I have done the bounce dives and built up my confidance with short dives. I used to book dives for the sole reasion they were X deep and thats where I wanted to be.

Having done this for a couple of years i now have the mind set that if I cant do at least 30mins on it I am not interested as a result I no longer crave the deep wrecks and would much rather do longer dives in the 50-80zone.

I have got into trouble saying this before but I dont know why? It's just my opinion about my diving?


I slag off puddle diving and diving in rock tunnles so why cant I slag of bounce dives on 100m+ deep wrecks

ATB




Mark

PS I did dive with Ash on wrightys boat this year