First RB boat dive of season, what a CF!

[londonsean69]

Sunday 20 March - On Defiant out of Littlehampton

This is to be dive no 2 on my EDO-04, and it was the wreck of the Shirala.
I had planned for a bottom time of 45-60 Min.s, cold permitting (I only had 3mm gloves).

Everything is going perfectly, the unit is making all the right noises and feels good. Gas consumption is excellent.

Bang on 40 Mins. I hear gas escaping, and lots of it!! I quickly determine it is the right post so shut it down. By now, the adrenaline is going, and the bowels are twitching! I switch to OC on my KISS DSV to send up my SMB. I turn the right post back on and everything seems OK now. I switch back to SCR and begin my ascent.

At 16m, my Suunto Vyper beeps, reverts back to air, and tells me I have 147 minutes of stops!!! Good job I carry a d-timer and tables, OH BUGGER, lent the d-timer to Frank on the boat as his Aladdin died when he turned it on. I still had my watch, and have a knot at 6m in my SMB line, so no bother, slow reeled up then hung for 8 @ 6m.

Back on the boat, my (empty) electronics housings have flooded and the suunto is in a major sulk. Still, dive No. 2 beckons, The Mulberries.

I checked pressures, 160 Bar left in the L/H 7l (190 starting), didn't check the right (leaking) cylinder (TWAT!), couldn't find the source of the leak, so decided to dive the mulberries on my (reclaimed) D-timer. Dive went without a hitch, but I seemed to be using loads of gas.

Slowly, after 3/4 of an hour, I realised why. I thought I was just using a lot in my suit because of the up and down profile on the mulberries. What was actually happening, was the leaky cylinder was empty, so I was breathing out of 1 7l, instead of 2. I still had 80 bar in the remaining 7l so just sent up the bag and did a safety stop.

The leak from the right post was caused by my inhalation hose pulling against the din 1st stage, and unscrewing it. The flooded PPO2 housing was caused by my shabby workmanship, and the computer crapped out because of the cold and a low battery.

Solutions;
Fit some 90 degree adaptors to the first stages to allow cleaner hose routing. Also, play with the positioning of the cylinders on the SCR.
Fit SPG to right cylinder.
Build better housings!!
Fit new computer battery.

The good news is, the SCR is doing a brilliant job of gas extension, on the Shirala, I had an SAC of 3l/min, this included suit inflation and OC!! On the Mulberries, this was more like 5l/min, probably due to the amount of gas in the suit with the up and down profile.

[And]

Hi

Nice report Sean

Are the cylinders manifolded, or are you diving them as independents ?

Andy

PS Don't worry, saw the pics elsewhere. Its independents

[londonsean69]

Originally Posted by And

Hi

Nice report Sean

Are the cylinders manifolded, or are you diving them as independents ?

Andy

PS Don't worry, saw the pics elsewhere. Its independents

I am trying to work out how to put a manifold on them, rather than just buying the Halcyon one. Has been the theme of the project really, just to see CAN I do it or design it, rather than just saving money.

[And]

Hi

AFAIUI it is just a normal manifold, except at one end of the isolator there is a hose (either normal HP rubber or stainless wire covered, kind of like 'proper' bike brake hoses) which connects to the other post. I've also seen setups with two isolators linked with a hose, but thats on the big twin 20 ltr setups.

If I remember rightly there is some good info inluding pics on a mexico DIR site, as Danny uses an RB80. They also recommend the steel fram rather than the straps, to ensure the manifold isn't stressed and the breather can't move about.

Andy

PS. Sorry, done a quick google and the website isn't there anymore. It was akumaldircenter.com The EKPP site might have better pics. Also check out 5thD-x or whatever its called as they have piccies from RB80 courses.

[londonsean69]

Originally Posted by And

Hi

AFAIUI it is just a normal manifold, except at one end of the isolator there is a hose (either normal HP rubber or stainless wire covered, kind of like 'proper' bike brake hoses) which connects to the other post.

I've got that far It's just thay want about £350 for the manifold. I have MDE modular valves, and will have the L/H valve plug tapped to take a 1/4" BSP. This will then have 12" of flexible stainless (the stuff used on fill whips). I just have to work out how to get the flexible line onto the center isolator. As the isolator section is hollow (obviously), and the metal thickens up towards the isolator valve, there will be a point where the walls are thick enough to take drilling and tapping for the other end of the flecible hose. Its just working it out, and then having faith in the strength of it once tapped (not by me, will get a machine shop to do it)

I have it on the straps for the moment, but will be having a stainless frame fabricated. With 2x7l fabers I feel that there is not too much stress on the unit, especially in the water! Plus, the straps are better for travelling. With the longer flexible hose, misalignment becomes a non-issue.

Cheers

[beanie]

if its MDE a manifold ould you not use a DIN to 1/4 BSP adaptor? I beleive the MDE manifold is 5/8 BSP same as DIN?

could of course be speaking BS again though

[londonsean69]

Originally Posted by beanie

if its MDE a manifold ould you not use a DIN to 1/4 BSP adaptor? I beleive the MDE manifold is 5/8 BSP same as DIN?

could of course be speaking BS again though

You could be right, I remember asking this at my LDS. Thing is, aren't they handed?? Doesn't matter if they are, just have to put the isolator valve on the easiest side (eg. the one with R/H din thread).

Cheers

[aquaholic]

Sean,

Good report. Thanks for sharing your troubles. One miore reson for using larger tanks on RBs.. you have more gas to loose slowly, and more time to react

I have been thinking along similar lines to manifold my 7 L's on the KISS.
I took my old style MDE isolation centre appart and it looked to me that the inner centre thread is a Male DIN fitting. Hence the outer thread should be female and give you a ready adapter to go on the old style MDE pillar valve, rather than habing to drill through a plug. Haven't had time to try this out as my tanks are all full... but will report back when I get a chance.

As far as I remember, the new MDE isolation centre and pillar valve connections are standard DIN (female at the Pillar valve end, male at the centre end) - so a female to male decanting whip should do the trick nicely .

Where are you going to get your stainless frame made? Would also be interested in one of those for the KISS if the centre stay could be adapted to bolt into the KISS CL case...

Keep us posted

Anke

[NotDeadYet]

Originally Posted by beanie

if its MDE a manifold ould you not use a DIN to 1/4 BSP adaptor? I beleive the MDE manifold is 5/8 BSP same as DIN?

could of course be speaking BS again though

Old ones were... woo-hoo, you could use a dismantled manifold for an emergency decanting kit when you realised you didn't bring one and the nearest shop is 200 miles away

New ones are different.

[londonsean69]

Originally Posted by aquaholic

As far as I remember, the new MDE isolation centre and pillar valve connections are standard DIN (female at the Pillar valve end, male at the centre end) - so a female to male decanting whip should do the trick nicely .

Where are you going to get your stainless frame made? Would also be interested in one of those for the KISS if the centre stay could be adapted to bolt into the KISS CL case...

Mine are the new kind, and I am 90% certain they are DIN, however, I am also 90% certain that one of them has a left hand thread. It is how you adjust twinsets, to make them parrallel, by turning the centre isolator, therefore one HAS to be L/H. This however, would not be a problem, as I would just mount the isolator on the L/H thread, and have the flexible on the R/H, and a M-F decanting whip would be perfect, but, probably far too long.

However, sub-aqua do all the bits and bobs necessary.
Female Din ( 232 bar ) To 1/4 Bsp Female - Goes on the centre piece.
Adaptor Brass 1/4m X 1/4m Bsp - To fit the above adaptor to the flexible hose
02 Hose/Polymid/Nylon Core/1/4 X 50 Cm - Flexible hose with 1/4" bsp femal swivels (may use the stainless one)
Din Adaptor To 1/4 Bsp Ml (232 Bar) - Screws into the pillar valve

Hopefully, once full assembled, the whole jobby shouldn't be too bulky, whilst offering even more backup over independents.

As for the stainless frame, I am in the middle of the drawing, and will just approach a couple of marine stainless fabricators.