Spheres

Skipbreather

I’ve been down this path already to some degree when a friend was working on a clean sheet of paper conversion of a BP60. Yes, a Tinkertoy compared to a MK 15.X, but the center section form factors raise the same issues.

The center section needs to be close to its original position on the back in order to get the breathing dynamics right. Then layout a pair of even just Faber 13 cf lp bottles side by side below it and envision how TALL the resulting enclosed space will be. I actually designed and built the base of a case for him, complete w/ the 15 ~ 20 degree (I forget the exact angle) bend below the shoulder blades. The base enclosed everything including the valves and regs. If you’re 6’4” like me it would work fine but on most folks it would look like the old Halcyon ‘Fridge. Travel would be problematical.

All that said, if someone were to donate a MK15.5 (not 15) center section complete with scrubber and dome so I could fabricate a prototype, I’m sure I could come up w/ something usable. The center section, scrubber, and dome would unfortunately get “destroyed” in the process and be unreturnable. (That’s my story and I’m stickin’ to it… )



I LOVE the smell of epoxy in the morning!

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"Entropy RULES! Enjoy the interim."

Dave Sutton

Ken,

I was thinking more of 2 liter bottles mounted horizontally, a-la BMR-500. Height would be dictated by desired seated-height for dressing. Cylinder valve handles would protrude left and right from the sides of the new chassis. It's actually pretty simple.


Dave

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"Changes in Lattitudes, Changes in Attitudes, Nothing remains quite the same".... www.nobubblediving.com

spottydog

Has anyone got some photo's of the Eagle.
I think this is the arrangement that is being used.

caveseeker7

The Colkan Eagle has one tank inside the case, mounted horizontally.
The diluent tank is mounted below the case. Check post #4 in thread below:
Colkan Eagle-First chamber dives and pictures

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Cheers
Stefan



"Political Correctness is a doctrine, fostered by a delusional, illogical minority,
and rabidly promoted by an unscrupulous mainstream media,
which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.!"

Skipbreather

Hi Dave-

Having put quite a few hours on a *highly* tweaked ‘500, it’s probably fair to say I’ve got a somewhat more charitable attitude than most towards that particular sow’s ear. That said, the valve placement was it’s sorest point for me and I’ve got orangutan length arms. O2 shutdown was do-able in wetsuit but tough diving dry. Dil was just not do-able for me even wet.

The tanks themselves, however, are actually pretty sweet. They are short, fat 13 cf cylinders, DOT 3AL3000 rated so no fill issues. The size is nominally 4.5” d x 10” tall, same tank used in some Lar V’s. If playing with mating them to a 15.5 center section, I’d set them up threads down w/ Inspo “T” type valves. Would keep overall height reasonable. Valve threads would most likely need tweaking, but I’ve seen threads of 5/8-18, ¾-16, and 7/8-14 on these tanks so all could be turned from a std ¾ NPSM valve. Being “T” type, alignment in the 4 jaw would be at least *somewhat* less problematical than other type valves. Set up the rig w/ Hammerhead controllers and there would be essentially no electronics inside the case & no Bendix issues.

Custom case for something like that would be a piece of cake. First draft most likely in just e- glass type fiberglass- easy to lay up & cut/ shape/ modify. Perhaps pull a mold from it. Final version in Kevlar- carbon once dimensions are set.

Does get the gears spinning, doesn’t it?

Best,
Ken

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"Entropy RULES! Enjoy the interim."

decoweenie

From personal experience since the BMR-500 (nickname POS-500) was the very first CCR I have ever used, diluent isolation was definitely impossible.

And I am a yoga-master...

Sandy

I've been playing with a BP 60 centre section for a year or more now and have settled on 3 cylinders. Two 1.5 litre cylinders with a twinset bridging them to make a total volume of 3 litres and a single 1.5 nestled between them for oxygen. The tiny cylinders were the only way to keep the width of the design down (under 45 cm). And they were cheap. I've rebuilt the chassis from fiberglass to hold it all together. I'm on a second version of the chassis at the moment to get it a little more tidy. (posted some pics a while back - search "modified biopak" under the gallery)

Just a quick MK15 question. What is the most common place to wear lead that you can still dump in an emergency? A standard belt would seem to interfere with the fit of the backplate behind you unless you let it hang halfway down your bum or keep it at the sides only.
Cheers,
Sandy

Dave Sutton

With the old military harness.. it's uncomfortable.

Replace it with a backplate and you can wear a standard belt. I use weights on the sides...

Have one rig set up with Halcyon weight pockets and it's great.

Dave

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"Changes in Lattitudes, Changes in Attitudes, Nothing remains quite the same".... www.nobubblediving.com

koputai

I tried a fibre cylinder for fit a few years back, and it seems there is plenty of room. I think it was a 2L, but maybe 1.5L. You could run O2 in this on board, and have you dil in your off-board sling. No worries. Or, with a strip out and re-plumb, you could run two of them internally. Not nearly as good as two 3L sphere's though.
fibrein15.jpg

Cheers,
Jason.

Dave Sutton

Hey Jason..

Nice photo to show the area. Not a lot of room left for a pod, though...

??

Or were you planning a mCCR using a secondary only?


Dave

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"Changes in Lattitudes, Changes in Attitudes, Nothing remains quite the same".... www.nobubblediving.com