[PSUBS-MAILIST] R300 Dive report - Canyon Lake, Tx

Tue Sep 1 22:13:43 EDT 2015

Hi Cliff,thanks for the report.Perhaps the motors got really hot & siezed a bit. Just adding some oil to the systemwould help that a lot if that were the case. The beauty of the compensating system you have is that youcan easily do that.There may be more current draw on the vertical thrusters as they are trying to push the sub sideways through the water & hence more heat or an over current situation. Some controllers have overcurrent protection.Moving from forward to reverse rapidly mightn't help.Let us know if you come up with an answer.Alan
      From: Private via Personal_Submersibles <personal_submersibles at psubs.org>
 To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
 Sent: Wednesday, September 2, 2015 1:39 PM
 Subject: Re: [PSUBS-MAILIST] R300 Dive report - Canyon Lake, Tx

Wonderful detailed report Cliff! My theory is a thermal shutdown of the controllers as Hank suggested. Although I have no documentation on their speed controllers, the fact it fixed itself suggests that. But then on the other hand why did it take all that switching on and off to reset?
This reinforces my intention to put a speed controller override into the new boat.
Best,
Alec

On Sep 1, 2015, at 5:40 PM, Cliff Redus via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

Itook the R300 out this weekend.  This wasthe first time to have it back in water since the 2013 Psub convention in Islamorada.  The objective of the dive was to evaluate somefairly significant modifications.
Toimprove low speed maneuverability and reduce noise, I junked the jet pump and aileronsand went to four fixed MK 101 thrusters. I also junked the VBT and just add ballastto get neutral. Also I added a Garmin AIRMAR DST800 Smart Sensor to measurealtitude, speed and water temperature. It worked great.  Installed a newLED 5k light, upgraded to a new HMI, and changed the foot and joystick controls. I also rewired the main battery bank for36VDC rather than 120VDC and installed four MK 101 motor controllers.  I modified the aft horizontal MK-101s byadding Kort nozzles and used air to pressure compensate.  I used the same pressure reducing regulatorHugh Fulton posted about awhile back that he is using on the QSub.    The changesdecreased the weight of boat by 200 lbs while the displacement remained thesame.   Myson, wife, a diving friend and I took the boat to Canyon Lake in Texas thisSunday.  Visibility was less than 5 ft socould not see much.  My main interest atthis point was just to get into water.  Afterlaunching the boat, I did some testing to get the base line ballast both mid-shipand in the stern correct so that I could get neutral and trim after floodingthe MBT.  After establishing the fixedballast, I took the boat out to test how the horizontal thrusters work forsurface maneuvering.   I was very happywith way the horizontal thrusters performed. Surface maneuverability wasexcellent and these motors are supper quite. I did find that you could cavitate the props on the surface if you hitit with too much power. As before the changes, when you get up to about 4knots, the bow wave obscures the pilots vision.   Breaking is much improved and it is nowpossible to rotate on the surface or in the water column. Ithen took the boat out for the first submerged maneuvering.  The vertical thrusters were very effectivefor depth control, pitch and roll control.  I found that it was much easier to get tospecific depth and hold this depth using the vertical thrusters than the oldway I did it with the VBT.  They workedgreat.  While removing the VBT simplifieddive operations, it did result in loss of freeboard of about 1 inch.  This is a downside of removing the VBT as thefreeboard was already quite low.  I just haveto be careful when opening the hatch.  Iopened and closed that hatch throughout the day and only took splash one timewhen a boat came by I did not see. Thenew Garmin AIRMAR DST800 Smart Sensor worked great. With visibility less than 5ft, being able to know the altitude was very helpful on dives. As usual, it gotdarker as you descend but knowing when the bottom was coming up was nice.   Onthe negative side, during the last dive of the day, the vertical thrustersfailed while my son was on bottom in about 27 ft of water.  He had to surface using the MBT. Why thesethrusters failed is a mystery.  It was atthe end of the day and I had pushed the batteries pretty hard all day along butwe still had plenty of battery voltage.  My sons second attempt to surfacewas to put some air in the forward MBT to lift the nose and then use the aft horizontalthrusters to power to the surface.  Thisfailed as aft horizontal thrusters were not responsive.  After surfacing with the MBT, we discoveredthat tree limb about 1.5” diameter had lodged in the starboard horizontal thrusterbetween the prop and the Kort nozzle. This explains why we lost horizontal thrust but not vertical.  After getting the boat back on the trailer, Itested the vertical thrusters.  Theywould barely turn even when giving them full power.  My first guess was that the air pressure compensationsystem failed and the thrusters were full of water.  When I got the boat back to my workshop, Idisassembled both vertical thrusters and discovered they were dry. After rechargingthe boat, I tried the vertical thrusters again and got the same slow speedoperation.  After turning them off and onfor about five minutes, the starboard vertical thruster stared workingcorrectly.  I kept switching the portvertical thruster off and on and all of a sudden, it began working correctly.  When I had the motors apart, I put amultimeter on the wires going to the brushes and found it showing 35VDC.  At this point the control signal to thesemotors was 2.5V so voltage to the motors should have been zero.   My guess is that the MK motor controller isacting up.  But it is strange that boththe vertical controllers would fail. Also, if it were  bad motor controllers, then why did they both start workingagain.  This is still a head stumper forme.  Alsotowards the end of the day, the OTS underwater communication stared acting up.  Base and standby diver using an OTS Guardianfull face mask could hear underwater transmissions from me but I could notreceive either from the diver or from the base. The underwater commns had been working great for the previous 7 hours.   I wasalso having trouble about this time with the VHF radio that Alec gave me.  Again I could not receive.  When I get a chance I am going to see if theconnection to the antenna got disconnected. Oneof the nice new features of the new HMI besides being larger and having a higherresolution, was it has built in data logging. So after the dive it was very nice to be able to download into Excel about50 variables logged at a one minute interval. I was able to plot these and geta detailed picture of how all the ship systems were working during the day. Ifanyone has any thoughts on why the vertical MK 101 thruster motors failed, orhave had any negative experience with the MK101 motor controllers, I would loveto hear them.  When they are working, theyare great. Allin all, I was very happy with the changes but have a few kinks to work outbefore I take her out again.  Now if I could just find some clear water to dive in, I would be a happy camper!
Cliff

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