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Yesterday, after several months, I finally finished my RCABS and could hardly wait to get my boat in the tub to check it out. Since I hadn't trimmed the boat I thought the best thing to do would be to start off with the bladder inflated when I put the boat in the water.
So I turned on the TX, switched on the ESC and tested the systems. Everything worked fine during the bench test. Bladder inflated and deflated just as designed. Then I carefully inserted the forward end cap, vented the cylinder thru the Schrader valve, and did a visual check of the O-ring to ensure a tight fit. Some of you may already see the problem.
The boat sat level in the water and I thought great, I won't have to worry about surface trim. Then I signaled the Clippard valve to vent the bladder. The boat started to dive, slowly at first then faster, bow first.
That's when I noticed air bubbles coming up as the bow dropped even faster. A signal to the pump started to bring the boat up then quickly to the bottom of the tub.
Brought the boat out of the water, out to the bench and opened it up. I found the forward end cap off, and water in the cylinder. While letting the blow dryer run on the parts I sat down and started writing out step by step what I had done and what I saw happening.
It didn't take long to realize I had inflated the bladder with the end cap off the forward cylinder that housed the air pump and the Clippard valve. When I put the end cap into the cylinder and vented thru the Schrader valve the bladder pressure was greater than the pressure in the cylinder. Venting the bladder thru the Clippard valve overpressured the cylinder pushing out the end cap and allowing water to enter.
The story doesn't end here though. By continuing to run the air pump after water entered the cylinder, I had pumped water back into the bladder!
Had I installed the end cap before inflating the bladder, there would have been a pressure difference between the cylinder and bladder that likely would have equalized when the bladder was vented to dive the boat.
I was lucky in that I was able to save the Clippard valve, the Jomar switch and the air pump. The ESC however was damaged beyond repair.
Bill Rogers
#1255
So I turned on the TX, switched on the ESC and tested the systems. Everything worked fine during the bench test. Bladder inflated and deflated just as designed. Then I carefully inserted the forward end cap, vented the cylinder thru the Schrader valve, and did a visual check of the O-ring to ensure a tight fit. Some of you may already see the problem.
The boat sat level in the water and I thought great, I won't have to worry about surface trim. Then I signaled the Clippard valve to vent the bladder. The boat started to dive, slowly at first then faster, bow first.
That's when I noticed air bubbles coming up as the bow dropped even faster. A signal to the pump started to bring the boat up then quickly to the bottom of the tub.
Brought the boat out of the water, out to the bench and opened it up. I found the forward end cap off, and water in the cylinder. While letting the blow dryer run on the parts I sat down and started writing out step by step what I had done and what I saw happening.
It didn't take long to realize I had inflated the bladder with the end cap off the forward cylinder that housed the air pump and the Clippard valve. When I put the end cap into the cylinder and vented thru the Schrader valve the bladder pressure was greater than the pressure in the cylinder. Venting the bladder thru the Clippard valve overpressured the cylinder pushing out the end cap and allowing water to enter.
The story doesn't end here though. By continuing to run the air pump after water entered the cylinder, I had pumped water back into the bladder!
Had I installed the end cap before inflating the bladder, there would have been a pressure difference between the cylinder and bladder that likely would have equalized when the bladder was vented to dive the boat.
I was lucky in that I was able to save the Clippard valve, the Jomar switch and the air pump. The ESC however was damaged beyond repair.
Bill Rogers
#1255
BD.
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