[PSUBS-MAILIST] Listing solved

Sat Jun 18 13:01:45 EDT 2016

Hi David,My thrusters would not have the power to stop that assent.  Maybe DW thrusters could do it.  I will fix the problem and it won't happen again.  It is dangerous to dive so heavy because the drop weight may not be heavy enough to surface the sub if out of air.  Oh wait a minute,, I have an escape  vehicle with a vertical orientation stability bladder ;-) ;-)  Hank 

    On Saturday, June 18, 2016 9:30 AM, David Colombo via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

 Hank, sounds like quite a ride. Do you think you could have controlled the ascent with your thrusters? Maybe Cliff could write some plc code for rotational control with the use of accelerometers to automatically control the thrusters in such an event.
David ColomboOn Jun 18, 2016 5:25 AM, "hank pronk via Personal_Submersibles" <personal_submersibles at psubs.org> wrote:

Alan,I am using air water valves for venting only.  I have had  great success with similar on  my under water log salvage ROV.  I am in fresh water so not an issue for me.  I have not seen Vance's design but assume you need an air line to each valve and a means of regulating air pressure to the valve.  I looked at using air but it was getting complicated.  I thought ComSub had solenoid valves? No?Hank 

    On Saturday, June 18, 2016 5:58 AM, Alan James via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

 Hank,what sort of solenoids are you using? Are they for both filling & venting?I have solenoids for both on my ambient & use them in salt water, but afterpulling some apart I wasn't that happy that they would last the distance.I remember Hugh saying he hadn't had much luck finding a descentsolenoid valve to do that job, & he imports & makes valves.I am going to use Vance's pneumatically operated top hat valve design.Alan

      From: hank pronk via Personal_Submersibles <personal_submersibles at psubs.org>
 To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
 Sent: Saturday, June 18, 2016 11:31 PM
 Subject: Re: [PSUBS-MAILIST] Listing solved

Hi Brian,The sub was spinning like when a helicopter loses its tail rotor.  It seemed pretty fast also, I am guessing four revolutions but I was't counting.  I have never experienced that, it was very weird.  Its funny though because in the few seconds it took to surface I said to myself "I wonder if this is what Alec was talking about"  because he had an issue with Snoopy rotating but under different circumstances.  Hank 

    On Saturday, June 18, 2016 2:58 AM, Brian Cox via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

 Hank,  When you say you did " 4 full rotations"  Do you mean rocking from one side the other on the way up?   What maximum angle from center do you estimate you were swinging?  If I'm understanding you right. That extra air was no doubt compressing on the way down , making you accelerate. Brian   

--- personal_submersibles at psubs.org wrote:

From: hank pronk via Personal_Submersibles <personal_submersibles at psubs.org>
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org>
Subject: [PSUBS-MAILIST] Listing solved
Date: Fri, 17 Jun 2016 20:40:55 +0000 (UTC)

Today I dove Gamma to 80 feet and the cause of my list became clear.  First off I extended my bottom vent tubes on the front MBT's and that fixed the list once surfaced.  But the real problem was quite scary.  It turns out that I am not evacuating all the air from my MBT's because there is not enough height difference between the vent valve and the tanks.  I added about 200 lbs more weight than my calculations called for and that compensated for the trapped air.  Now, I am no math wiz, so I chalked it up to a math error.   When the sub is on an angle the air does not escape fully.  I did my dive and vented till the sub was under and let her sink.  I was not paying attention to the sink rate because I expected it to sink slowly thinking all the air was out of the MBT's.  I was more concerned about the first time diving after all the modifications I have done.  I have not done a deep test yet.  Well I hit the bottom like a ton of bricks and Gamma went into the mud pretty deep I guess, because I had to use up 500 psi of air get it loose from the bottom.  Once it was free, I was a rocket heading to the surface and the sub did about 4 full rotations on the way up and then It breached.  Man that was freaky, so now I know the sub is too heavy because the air is trapped in the MBT's.    There is an easy solution, I will mount manual vent valves to the tanks and rotate them with linkages from the main vent valve.  I will leave the existing lines in place to get the air into the tanks but the extra valves will do the venting as well as the original vent valves.Hank
Oh ya and my hip waders had another leak.
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