Chest Mounting a RAM

[MK15diver]

I just came up with a weird idea as with all my weird ideas I am trying to see how wel it might work. As we all know, the closer a double hose is to your lungs the better it will breath and so I came up with the idea of making a front mounted harness for my RAM. I was thinking about mounting it certer to my chest. As for the air supply I was thinking about using my double LP 85's and feeding a LP line into the hookah port via a 2nd stage hose. The only thing I really need is a specially machined plug to fit in where the HP Nozzle is to prevent air leakage and water from entering. I don't really need a HP Nozzle sense it is fed by LP only. Can anyone make such a plug?

[olkev]

So, you are looking to do something like this?



It's a modified Royal Mistral. Looks like a first stage on the yoke and a low pressure hose coming under the left arm. Ryan Spence would be your best source as to how this was hooked up. I just kinda wonder how the exhaust bubble situation would be.

[INFIDELxx]

Great question! And thanks for posting that picture...It's my new wallpaper!

[olkev]

Glad you like the pic . . . maybe you will like this one too . . .



But, I'm anxious to see if Ryan views this thread and can shed some light on how this was hooked up.

[WD8CDH]

So, you are looking to do something like this?



It's a modified Royal Mistral. Looks like a first stage on the yoke and a low pressure hose coming under the left arm. Ryan Spence would be your best source as to how this was hooked up. I just kinda wonder how the exhaust bubble situation would be.

Do you like those welded cylinders?

As you can see, Cousteau fed a single stage regulator with low pressure so it was breathing easy just like a Mistral at low tank pressure.

To chest mount a RAM, I would just buy a DA nozzle from Bryan and plug it by threading it 9/16" x 18 or 9/16" x 24 and inserting a short set screw with thread sealant. Bryan may even have a damaged nozzle he would sell cheap. You could also just remove the guts of the DA nozzle except for the seat, put some epoxy inside of the nozzle and put the parts back in. Either would probably be cheaper than custom machining a 7/8" x 18 (if I remember correctly) plug from scratch.

[luis]

During Sand Dog IV I tested a new Mistral on a chest mounted configuration. Since the first and second stage can be easily separated, it made it very easy to try it in this configuration.

I will say that this was probably the best breathing new Mistral configuration you will find. Chest mounting does make a DH breath a lot easier when you are in the normal swimming position. Even a new Mistral performs well in this configuration.

The down side is the complication of chest mounting and you get in a vertical position the bubbles will be in your way. On a swimming position the bubbles are not an issue… they go past your side.


I do have a drawing for a simple plug to replace the first stage on a RAM or DA, but as mentioned above it may be cheaper to get a ruined DA nozzle and try to plug it. For testing purpose you can just use a solid dust can on the yoke.

[WD8CDH]

For testing purposes with the dust cap like Luis suggested, you could place the exhaust can against your chest to keep the diaphram closest to your lungs.

Next question, where can you get shorter hoses for chest mounting?

[Nemrod]

If you were to chest mount my RAM it would freeflow. Nem

[JES]

If you were to chest mount my RAM it would freeflow. Nem

I'd be willing to bet that most RAMs aren't as finely tuned as yours is.

[luis]

If you were to chest mount my RAM it would freeflow. Nem

If the exhaust is right in front of the diaphragm it should not mater where you mount it.
I have been thinking about using sticky back tape and a little block of plastic to raise the duck bill closer to the diaphragm.

[Bryan]

When you get the phoenix setup with the silicone valves and duckbill you have to watch very closely because they can flow A TREMENDOUS volume of air through that corrugated hose!
Dive Rite or someone like that was offering custom length LP hoses.....I think Greg Barlow had some made. The Hookah port is actually a B Oxygen fitting so off the shelf stuff is a bit hard to come by. If you take one of the chrome octopus adapters I sell and get a LP hose with two male ends you could make it work easily...Again Ryan is the best source I know for the way Cousteau originally did it....

[captain]

I have a plug I made up years ago. PM me your address and I'll sent it.

[swimjim]

Here's a shot of Luis with his front mount new Mistral at SDIV

Jim

[WD8CDH]

<snip> The Hookah port is actually a B Oxygen fitting <snip>....

Hi Bryan,

Any idea what the CGA number for the fitting is?

[Nemrod]

If you were to chest mount my RAM it would freeflow. Nem

If the exhaust is right in front of the diaphragm it should not mater where you mount it.
I have been thinking about using sticky back tape and a little block of plastic to raise the duck bill closer to the diaphragm.

Don't take it out of your mouth without a DSV, now, where did I put that Luis Special DSV?!

If I roll on my back, I can feel positive pressure at the mouthpiece, if I remove it from my mouth (while upside down) there is an explosion of bubbles that will dump prodigious amounts of breathing gas rapidly into the ocean. I suppose for vertical oriented divers chest mounting makers sense as if you were wearing lead boots and walking on the floor of the sea but since we strive for horizontal swimming positioning then chest mounting a finely tuned, high performance dual stage like the RAM might not be a practical idea. I get the single stage given the higher cracking force. As well, not to dismiss Cousteau, but just because he did something does not mean it was a smart thing, like putting fish in a plastic bubble and watching them torment themselves, lol.

Well, it will be an interesting experiment. Give it a try.

Nem