Bardo and Boris sitting in a tree... ;)

[And]

Originally Posted by Clare Gledhill

Rock bottom (minimum gas) calculations change at Tech 2. When you did DIRF you were still encouraged to use the starting claculations to inform yoru choices based on your real diving experiences.

Hi

Before anyone jumps on this, minimum gas calcs do not 'change' although the figure used for breathing rates will be reduced to something approaching your real rate. The requirement is still that you need enough gas to get you and a buddy to the next available gas.

I personally think 100bar is too low, but in the end it is up to the divers what reserve they choose to have, with the caveat being that Murphy, not JJ, will eventually come along and check how accurate your figures are .

ATEOTD CCR is LESS expensive over the long run than OC trimix, and the gas savings are clear. There are also many more advantages and disadvantages to consider. I don't think we all need to start comparing spreadsheets and invoices do we?

Good on Bardo for trying it out, but lets not spoil a good post with a predictable 'debate'.

Andy

[MATTBIN]

If I was Jason and MY thread had been so blatantly hijacked I would DEMAND AN APOLOGY.

Nice report on Boris, sadly not only will I never buy an RB I most definitely wouldnt buy a Boris, purely financial reasons, well that and I have a morbid fear that my chuck-it-in-the-corner-till-next-dive attitude might not be the best way forward with an RB. I KNOW they are evil dangerous things, my wife said she'd kill me if I bought one.

But if she 'leaves' me, I'll be down to Cornwall quicker than a quick thing being chased by a slightly less quick thing.

Matt

[And]

Hi

Incidentally, what is the scrubber duration for ouroborus? It doesn't say on the website.

Andy

[Mark Chase]

[quote]

Originally Posted by Clare Gledhill

Mark - that's really not on.

The gas figures I gave you were based on actual dives that i did last weekend - not with Al - but with a GUE team.

I posed the question about 40-45mins at 70m costing £150 in gas and i was told I was talkig rubbish and the dive cost £50-60. Then i am given figures for 18/45 bassed on 35mins bottom time including decent???????

These figures are not relevent and would not be correct for the dive I put forward.

We used 18/45 for the Pangani and the Illinois. Pangani was a bit deeper than planned 15/55 would have been a better bottom gas for where we landed on it.

I have dived the Illinois and dispite it being 68 to the sea bed its only 55 to the deck so its not an ideal example of a 70m dive. However the pangarny is a good 65m dive to the deck and I hit 69m without leaving the wreck.

18/45 may well be doable for that dive but its definatly not DIR

I use just under 10 bar a minute out of an Ali 80 at 65 metres. That's 20 minutes on a stage including descent and about 20 bar left for protecting the reg.

Which is another way of saying 15lpm actualy 15.5lpm

On OC Id plan 15lpm for the bottom phase and Id do about 12-13. If My SAC was 15.5 id be planning on 18

So my gas plan is still generous.


By the way with TDI we are trained to plan these events on a 40lpmin so I am again being genorous with 30.

Rock bottom (minimum gas) calculations change at Tech 2. When you did DIRF you were still encouraged to use the starting claculations to inform yoru choices based on your real diving experiences.

?? Yoy still need to be able to abort the dive at potentialy maximum run point and get you and your buddy from the bottom to the 21m stop.

100 bar in twin 12s is 1200ltrs of gas. From 70 to 21m blowing off all stops and doing a 10m/min ascent is 50m or 5mins. Alowing for an elevated SAC of 30lpm X 2 divers 60lpm over 5mins at an average depth of 35m your using 270lpm and therefore have 4.44mins to get from the bottom to 21m

100bar is not quite enough gas and dosent allow for any stops on the way up. I havent done tec 1 or 2 but I cant see this as being correct.

We don't dive thirds unless in an overhead - that is what minimum gas caters for.

A mistake from me obviously 150bar is not thirds 100 bar is not even thirds . I ment minimum gas.

I did Mark.

But i was talking to All?

In Donegal I did 25 minutes BT on the Audacious (57),

So thats not 45 @ 70 then

30 minutes on the Emprie Heritage (60)

still not 45 at 70

30 minutes on the Justicia (66)

Getting warmer but not there yet

and a shitty 20 minute dive on the Empire Adventurer (62)

Dam and you were so close

I used one twin set of gas that I took with me, four bottom stages (2 x 18/45 and 2 x 15/55) and two twinsets of 15/55 - returning home with nearly a full set aftre the Empire Adventurer dive was completed on a bottom stage alone - bar the ascent. All these figures do not take into account descent time so add on a bit for comparison. My gas bill for the week was £230 including all my deco gases. Loyal Watcher is not renowned for it's cheap gas prices (understandably he can't shift the volume)
At your calculations the gas would have cost me more than the boat.

None of which has any relevance to the dive i proposed which was 40-45mins at 70m

What would the gas cost for a dive 45mins at 70m including a 5min decent so 40mins avg depth say 65m on DIR standard gas.

For me getting the gas from Kent Diving or Dive Macheen in Tonbridge its about £180 per dive.

ATB

Mark Chase

[Mark Chase]

Originally Posted by And

Hi

Incidentally, what is the scrubber duration for ouroborus? It doesn't say on the website.

Andy

CE marked for three hours same as the inspo at 40RMV 5c water.

Dr Mike did 10 hours on it including dropping to 180m

Don Shirly did a similar depth on a HH modified Inspo and a similar run time

ATB

Mark Chase

[Mark Chase]

Originally Posted by MATTBIN

If I was Jason and MY thread had been so blatantly hijacked I would DEMAND AN APOLOGY.

Nice report on Boris, sadly not only will I never buy an RB I most definitely wouldnt buy a Boris, purely financial reasons, well that and I have a morbid fear that my chuck-it-in-the-corner-till-next-dive attitude might not be the best way forward with an RB. I KNOW they are evil dangerous things, my wife said she'd kill me if I bought one.

But if she 'leaves' me, I'll be down to Cornwall quicker than a quick thing being chased by a slightly less quick thing.

Matt

Quote from Bardos thread:

So what was the point of the post? Simple - to get you lot talking! In my opinion, it's important to keep an open mind to any developments in diving technology and procedures

We are talking arnt we. We are discussing the relitive merrits and down sides of OC / CCR.

I dont see that as much of a hijack but maby I mis read this bit.

ATB

Mark Chase

[Al_Star]

Mark - I'd been posting based in your earlier post.

Originally Posted by Mark Chase

Id argue that the CCR logically kicks in at 60m+ diving but id agree that in some circumstances OC is a better choice. Shallower than 50m you present rig is adequate, cost effective and safer.

Your example is deeper than 50m and in the 60m+ range. The figures I used were based on this range.

If you now are saying:

Originally Posted by Mark Chase

I posed the question about 40-45mins at 70m costing £150 in gas and i was told I was talkig rubbish and the dive cost £50-60. Then i am given figures for 18/45 bassed on 35mins bottom time including decent???????

Then you are asking a different question!

In terms of fills Breakwater turnaround is within an hour or two. We’ve turned up with a boatload of cylinders after a days diving and they’ve filled all the sets and deco stages by the time before they close. We do pre-arrange but they’ve done this for us on numerous trips this year at the prices I quoted. Like I said this is what we actually do, have done and will continue to do.

I don’t disagree that Rebreather’s are cheaper to get fills. Neither do I disagree that the OC filling logistics can be painful. What I am trying to point out is that the cost difference and logistics are not always the huge barrier they are presented to be. Most people get Rebreather’s because they like them. The fact they cost thousands rather defeats the cost saving argument in the short term – even accepting you’ll break even over many years. Chances are you’ll have upgraded from your original unit by then by adding HUD’s, new electronics, shearwaters etc. (Don’t suppose you know anyone whose done that? ). You’ll also find it hard to find anyone who’s spent thousands ever say they think it was a bad idea!

I’m a bit of a gadget fan and do think they are cool but I just can’t see the real need for one today. If I come into some money though I reserve the right to buy one for fun. I do believe they are less forgiving of errors but at the end of the day our lives are relatively risk free. If you can square that away in your own head and want to do it why not and make sure you have fun while you are at it.

Cheers
Al

[Mark Chase]

[quote]

Originally Posted by Al_Star

Mark - I'd been posting based in your earlier post.

Your example is deeper than 50m and in the 60m+ range. The figures I used were based on this range.

If you now are saying:

Errrrr I dont think so:


For the stuff i do with Delta we have to plan for 70m for the average dive and the occasional deeper one. Sometimes the weather has forced us on to wrecks in shallower water but most of the dives have been 60-65m with a sea bed around 70m and a 40-45min bottom time.

OC thats twin 18s of 16/55 a 10 of 50 and a 10 of 100%

Back gas and deco gas is going to set me back £150+ and i am going to need two sets of 18s and four 10s because there is no chance of a fill before the next days dive.


And Clares responce directly quoted the above paragraph and went on to say

Originally Posted by Clare Gledhill

I'm certainly not going to argue gas costs v breather costs with you Mark - it's been done to death and based on those emasures alone I'll lose.

But I will point out that the last two dives I did were exactly what you set out here - 70 metre sea bed and 65 metre average dive with a three hour ride out.

We do 30 minutes on the bottom (plus a descent time which you would include on your calcs as a 35 minute dive) so only 5 to 10 minutes less than you on twin 12s and bottom stage. One twin set lasts two days but we kill a bottom stage on each dive. Gets us round the fill problems too.

So two bottom stages @ £20
One twinset @ £38
Deco gases do two days too so £25

Gas costs £105 for two days or just over £50 a dive - a lot more money than the rebreather granted, but a lot less than the £150 a dive that you set out.

So Clare was responding to my question about a 70m dive

ATB

Mark Chase

[Mark Chase]

Originally Posted by Al_Star

In terms of fills Breakwater turnaround is within an hour or two.

Why is it I cant find a shop that will do this. They all insist on overnight for mix fills.

Do you Analise the mix with a Helium Analise? Is it accurate with such a fast fill?

I don’t disagree that Rebreather’s are cheaper to get fills. Neither do I disagree that the OC filling logistics can be painful. What I am trying to point out is that the cost difference and logistics are not always the huge barrier they are presented to be

.

How many dives could you afford to do at my local gas cost of £180

How many can you afford to do at £18 gas lime and consumables?

Its a big barrier for me.

Most people get Rebreather’s because they like them.

I hate them but I need them

The fact they cost thousands rather defeats the cost saving argument in the short term – even accepting you’ll break even over many years. Chances are you’ll have upgraded from your original unit by then by adding HUD’s, new electronics, shearwaters etc. (Don’t suppose you know anyone whose done that? ).

No. My unit recovered its full cost after 18months of diving

I sold my old CCR BOV HUD Travel frame etc etc and that financed the replacement.

I have made a profit of £175 Arguably because the unit had already paid for its self in gas I made a profit of £3975

I sold the two VR3s for £1000 and baught a Sherewater for £625

You’ll also find it hard to find anyone who’s spent thousands ever say they think it was a bad idea!

You obviously don't read my stuff much. i am constantly telling people its a bad idea unless the are doing at least 10+ deep 60m+ trimix dives a year.

I’m a bit of a gadget fan and do think they are cool but I just can’t see the real need for one today

.

Tech 2 and you soon will

If I come into some money though I reserve the right to buy one for fun. I do believe they are less forgiving of errors but at the end of the day our lives are relatively risk free. If you can square that away in your own head and want to do it why not and make sure you have fun while you are at it.

IMHO buying one for fun is mad. Its like buying a Caterham Superlite R for £38,000 and using it for an every day work car.

I see divers doing shallow diving on CCR and not having the excuse of film or photographs etc and I shake my head in disbelief. I just cant see what they find appealing about them.

Give me OC any day.



ATB

Mark Chase

[Janos]

Originally Posted by Mark Chase

IMHO buying one for fun is mad. Its like buying a Caterham Superlite R for £38,000 and using it for an every day work car.

I see divers doing shallow diving on CCR and not having the excuse of film or photographs etc and I shake my head in disbelief. I just cant see what they find appealing about them.

Mark, I've been mostly agreeing with you all the way (except when you're inlcuding the cost of the reserve when my shop will deduct that off) but now I must ask you to step outside

I really enjoy diving the KISS. I'm now happier on it than I was OC. Sometimes it is a bit of a pain to clean and to prep for the next day, but I quite enjoy kit faffing, and I like getting it just right. Plus it's warm and it's quiet.

Since diving the RB, I now come up because I've run out of wreck. On OC, it was because of gas limitations. This is a really novel experience for me.

True it is trying to kill me. But I look at that as a minor inconvenience.

Janos (Ripe for a fall...)

PS - Although I must admit that the first dive I did after passing my CCR mix course was a single tank dive to 30m on the Skye from the club rhib. [1]. And I loved it.



[1] - Just to piss ChrisCh off. I'd spell it rib usually...