(ABOVE PHOTO by Kevin Price)
Kevin Price has created a very well done and easy-to-follow step-by-step writeup on how to build our own RCABS WTC. He has kindly allowed me to post it for download here (diy-rcab.pdf). Thanks Kev!
RCABS ~ ReCirculating Air Ballast System
Originally develped in Europe, the RCABS ballast system has been around quite awhile, but Dr. Art Broder simplified the idea so that just about anyone with basic tools and a little ability, can build their own watertight cylinder. Using the pump and arm cuff from a blood pressure testing machine (you can now buy the parts without having to buy the whole machine), the system doesn't need to use Propel or other expensive and combustable compressed gas to function. Big Dave Welch sells RCABS kits for various size WTCs utilizing the RCABS principles (see the SubCommittee Vendors' page) and George "Crazy Ivan" Protchenko took RCABS one step farther and developed the Reverse-RCABS system. See Crazy Ivan's system on the following page.
H.L. Hunley RCABS
RCABS bladder installation on my scratch-built HL Hunley model. The rubber band loaded clear plastic over the blood pressure bladder helps press the bladder flat when I open the valve to submerge.
Compartment for air pump and valves
It turned out that the little airpump didn't have enough horsepower to pull a sufficient volume of air out of this small compartment to inflate the bladder so I had to run a jumper air line to the cylinder behind it that had more volume.
Here she is with the top hull half off.
BELOW - a 4 minute video from a local TV station about my Hunley model.