Water ballast system?

**sam reichart** · 11-01-2006, 08:47 PM

Re: Water ballast system?

Is this an acceptable totally â€œclosed-loopâ€ water ballast system?
To dive, pump starts to fill small bag inside closed cylinder, compressing air in cylinder. Foam baffle keeps bag compressed to keep water from sloshing around and fed to pump. To surface, reverse pump. Air P in cylinder assists pump-out.
An absolute backup could be a very small propel cylinder to pressurize the cylinder, compress the water-filled bag and expel water through dump valve â€“ the gas valve and dump valve being actuated by a SubSafe/servo.
Use two cylinders, independently controlled, to control level trim?

hmmm - can't upload an image now. Will post diagram later...

I'm pretty sure this is what OTW's current dive systems are designed to do...

**danl** · 11-01-2006, 11:14 PM

Here's a diagram. Do the

Here's a diagram. Do the added foam baffle to keep the water ballast from shifting and a two-way pumpto give positive dump vs relying on overpressure give any benefit over existing systems?

**crazy ivan** · 11-01-2006, 11:15 PM

This is a perfectly workable

This is a perfectly workable system, but the bag is not really necessary as long as the cylinder is properly baffled. I use such a system in my Fulton Nautilus. I do not use a reversable pump, I just open a solenoid bypass valve and the air pressure forces the water out. The propel backup is OK, but overkill IMHO.

**Guest** · 11-02-2006, 02:20 PM

If I built that system,

If I built that system, I would use a single centrally mounted bag, and build my main drive battery into a sliding tray that is connected to a servo.

The latter will provide a proportional trim system, which is much easier to control than twin tanks.

Andy

**mermaid** · 12-24-2006, 11:06 AM

http://www.subcommittee.com/forum/icon_question.gif I'm considering using a

I'm considering using a reverse RCABS system on my 1/72 Gato. Problem is the air pump only produces about 11-12 psi so my pressure tank will have to be about the same volume as my inflated bladder. Does a water pump produce more pressure? If so, it might be possible to set up a water ballast system that would be significantly more compact. I want to save as much space as possible! Comments?

**Guest** · 12-24-2006, 01:38 PM

Most gear style pumps and

Most gear style pumps and peristaltic pumps will achieve 15psi above atmospheric or higher. This will tail off as the battery voltage drops, which is a handy failsafe as you won't be able to flood your tank if the batterries are going.

Higher voltage pumps work best, 12 volt minimum spec.

Andy

**mermaid** · 12-24-2006, 02:10 PM

http://www.subcommittee.com/forum/icon_biggrin.gif Thanks Andy. Are ultra-miniature

Thanks Andy. Are ultra-miniature gear pumps available and if so, from where? I'm wondering how I'll be able to cram a 12V pack (two 6V NiMh or a LiPo?) into the 1/72 Gato hull and still have adequate capacity. The hull is long, but rather narrow so there is not all that much space to play with.

**Guest** · 12-25-2006, 12:23 PM

Something like this-

http://www.ripmax.com/Product_Images/large/l/l-ie63.jpg

http://www.ripmax.com/item.asp?itemid=L ... tegory=010

or

Something like this-

http://www.ripmax.com/item.asp?itemid=L ... tegory=010

or this-

http://www.ripmax.com/item.asp?itemid=L ... tegory=010
Either will work well.

You have space a plenty inside the Gato for any ballast system you choose.

Andy

**mermaid** · 12-25-2006, 12:37 PM

http://www.subcommittee.com/forum/icon_biggrin.gif Thanks Andy. I think

Thanks Andy. I think the multipurpose pump might be a better choice because it is intended to work with a variety of fluids including water. By the way, where is the multipurpose pump located on the site? I've been able to find the fuel pump under engines and accessories but not the other.

**Guest** · 12-25-2006, 02:05 PM

http://www.ripmax.com/item.asp?search=p ... submit.y=0

All pumps are

http://www.ripmax.com/item.asp?search=p ... submit.y=0

All pumps are at the above link. BTW, the orange fuel pump works great with water, I've seen one split apart (plastic innards) and they've been used for years by many model submariners.

**mermaid** · 12-25-2006, 02:12 PM

http://www.subcommittee.com/forum/icon_biggrin.gif Thanks Andy. Actually, although

Thanks Andy. Actually, although there are no dimensions, the orange pump appears to be smaller than the other. Are they approximately equal on pressure capability?

**Guest** · 12-26-2006, 05:19 AM

I've absolutely no idea, and

I've absolutely no idea, and to be honest it doesn't matter. Either will get the job done, you don't need to pump more than 17-20psi.

Andy

**mermaid** · 12-26-2006, 09:24 AM

http://www.subcommittee.com/forum/icon_biggrin.gif Thanks Andy. Good enough.

Thanks Andy. Good enough. Is a check valve required between the ballast tank and pump to prevent back-flow through the pump?

**Guest** · 12-26-2006, 09:52 AM

Yes you will need a

Yes you will need a valve of some description.