RCB VS GAS - performance depth

[wayne frey]

Has anyone run into a problem of limited depth with the RCB system? It occured to me as an occasional diver that the pressures as one goes down would be pretty hard to overcome pretty quick by the pump on an RCB.
I may be worring over nothing,but, it is a good question to post. How deep have people taken these without a problem, and if you had a problem,what was it?

[bigdave]

Hi Wayne,
That sounds like

Hi Wayne,
That sounds like a question for Dr Art. But I can say the way I ballast my systems it is not a problem. I ballast my RCABS so when the bladder is empty the sub is just negatively ballasted. So the deeper I dive the boat it cannot change the pressure on an empty bladder . When I want to surface I just pump in some air to get the depth I want. This works great for me, although where I usually run I do not go deeper than 4 FT. I hope this helps. Dave.



Edited By Bigdave on 1115899624

[wayne frey]

Just out of curiosity, how

Just out of curiosity, how far down has someone taken this system to test the limits?

[bigdave]

That would really be a

That would really be a question for Dr Art. But I know Steve Neill has had his down to 9FT with no problems. Dave.

[Guest]

I have brought my sub

I have brought my sub up from the lake bottom at about 10 feet depth with no problem at all. I have not run in deeper water, to my knowledge, but I would expect it to work by failsafe operation, or by radio command, if operational, at depths around 20 ft. That would be pushing the limit for most seals and other components as well as RCABS.
All you need is enough air volume in the WTC, and enough room for the bladder to expand.

[Guest]

The max pressure the compressor

The max pressure the compressor can pump would dictate the depth you can reach with the RCABS system.

Pressure increases at approximately 1/2 Ib per sq ft. for every foot you decend.

So, bearing that in mind, most of those little pumps used for RCABS can probably easily reach 7-8psi, you have about 15-16 feet of depth before your boat will struggle to surface.

Adequate for most people.

Andy

[boatbuilder1]

wayne that is a great

wayne that is a great question why didn't I think of that arrrrg
matey nail that mans foot to the deck arrrrr

seriously though here is another quandry would it help or hinder the rcbs if you pressurised the WTC up to say 15 to 18 psi ???????

charles

[Guest]

Don't think that would be

Don't think that would be a very good idea from a number of counts.

Not least would be the reason that, from what I've observed of Dave's WTC's, they're not designed to store pressurized air on the inside (you pull a vacuum with RCABS, don't you?)

There are ways of making a pressurized air system, but you want to be thinking outside of the RCABS box for that.

Andy

[kielbasa]

I may be totally off

I may be totally off base here, but aren't the motors that come with the WTC that Dave seel from a Blood pressure machine? I just had my blood pressure taken, and those little machines can put alot of air into those bladders. I have no idea what the actual psi is, but it seems to me (as inexperienced as I am at this) that we would worry about loosing the signal, before the system does not work.

also, at that depth, and with a pump only working marginally, wouldn't it only take a small amount of air in the bladder to start it moving up, as the sub comes up even a few more inches, the change in pressure would allow more air to be pumped in, and it would keep rising, and then you can pump in more air etc, etc,etc?

just my .02

[wayne frey]

I think it was Tim

I think it was Tim Smalley that showed signal response at 20 feet down before. 'Course, that's pretty darn deep for a model!
An interesting link of tests and theory. Sounds like 10 feet may be appraoching "crush depth", or do not exceed.
The San Gabriel, where Subron 5 has been running is 10-12 feet deep at max. Sounds like no problem.
Feedback is interesting though. Any others?

[tmsmalley]

Nope - not me Wayne.

Nope - not me Wayne. Never had the guts to go to 20 feet.
I have had my RCABS equipped Hunley down to 9 feet in a pool. I had lost signal by that time but the "Sub-Safe" kicked the pump on and the boat came up.



Edited By TMSmalley on 1115922179

[jsl]

Well.. We do use piston

Well.. We do use piston tanks instead of RCABS, but in terms of "crush depth" our polycarbonate WTC should be able to withstand the pressure at a depth of 24 meters or 80 ft. So the WTC should not be the problem.

If somebody could jam a manometer (pressure gauge) in the outlet from one of those small compressors and turn it on in free air, the pressure ratio could be found and the maximum depth calculated.

I'll get back to you when our Regulator project has taken the journey to the abyss at 24 meters...

(a much needed update on the project is underway)

Jacob

[Guest]

Wayne and others,
By Andy's figures,

Wayne and others,
By Andy's figures, the RCABS should work to at least 22ft depth, close to my estimate. The Smart Pump model AP-3P01 is rated for 11psi at 6V DC. Use it with confidence!

[wayne frey]

Arr Matey,
I will increase

Arr Matey,
I will increase my safe depth to 20 feet. The Alfa will need the edge to slip away from that Permit of Commander Crozier...
Run Silent, run deep, engauge creeper motors.
And Paul, those are not flood holes in the front of the Alfa

[PaulC]

I'm quite careful to keep

I'm quite careful to keep Thresher on this side of crush depth...

Waynes, between you and Gail it sounds like the San Gabriel is about to become Alfa infested. Rig for ultra quiet!