[PSUBS-MAILIST] DSV Aquatic update

Thu May 24 16:47:19 EDT 2018

The unit in mounted to the FRP cowling around my aft MBT.  As such water completely surrounds the transducer and I bring the wiring through the hull with a Subcon bulkhead penetrator. Only affect of pressure is to compress the potted transducer.  The transducer does not penetrate the pressure hull.

Cliff

Sent from my iPhone

> On May 24, 2018, at 3:32 PM, Alan via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> Cliff,
> if you are mounting it as a through hull; from a safety point the weak 
> link looks to be the plastic flange at the bottom that will take all the pressure. 
> I see there was a more expensive stainless unit.
> I guess if there was any doubt you could measure the thickness of the flange
> & calculate what pressure it would take before it sheared. I believe with plastics
> there is a 4x safety factor where human life is concerned, so it would need to
> take 600lb pressure. ( good project for your students lol)
> Cheers Alan
> 
> Sent from my iPad
> 
>> On 25/05/2018, at 7:42 AM, Cliff Redus via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>> 
>> The Airmar DST800 transduce unit is hard plastic and built like a tank.  There is a replaceable paddle wheel but no seals,.  Everything is potted.  I have had this transducer to 160 feet with no issues.  The units is designed for boats  as such the low depth number. Next month I will be diving the boat to 400 ft so will let you know if the transducer holds up.  The 230 depth rating I was mentioning has to do with the sounder functionality. After the unmanned dive to 400 ft I plan on diving manned to 300 ft to set max operating depth of the boat.  I will be able to tell you more after that dive as to what depth the unit stops sending the altitudes signals.
>> 
>> Cliff
>> 
>> 
>> 
>>> On Thu, May 24, 2018 at 12:53 PM, Alan via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>>> Cliff,
>>> just had a look at the Airmar link & it says depth rating 10 ft. ??
>>> How are you mounting it?
>>> I am intending using Canbus in my system. 
>>> Am using raspberry pi, a plc & extracting data from my motor 
>>> controllers with Arduino.
>>> Cheers Alan
>>> 
>>> 
>>> Sent from my iPad
>>> 
>>>> On 25/05/2018, at 4:33 AM, Cliff Redus via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>>>> 
>>>> I use an Airmar DST800  http://www.airmar.com/uploads/Brochures/dst800.pdf  for altitude and speed on the R300. Cost about $230.  It also give water tempertarure.  It would be compatible with what you have done as it sends results via serical communciaiton using NMEA 0183 prototcal.  The unit sends a series of ASCII strings for depth, speed and temperature that you would have to capture and parse to use.  I do this in my PLC.  The only down side I see for your boat is the depth spec which is about 230 ft.  I have seen a number of sounders that use NMEA 0183 serial or NEMA 2000 communication for sending altitude.
>>>> 
>>>> Some how Jon, I don't think I would find you sitting on the bottom at night on a 45 degree pitch,  inebriated, and calling for a lift bag!   But I do agree we can find all kinds of good reasons to add new stuff to our boats!
>>>> 
>>>> Cliff
>>>> 
>>>>> On Thu, May 24, 2018 at 10:55 AM, Jon Wallace via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>>>>> Cliff,
>>>>> 
>>>>> I will probably add altitude as soon as I can find a sensor that will interact with the Raspberry.  Also not shown is air tank pressure which will be added.
>>>>> 
>>>>> I agree that not all data is as important as others.  Regarding the pitch and roll, I agree with your assessment on that as well.  The pitch and roll outputs are "free", calculated as part of the digital compass heading which is tilt compensated, so I added them in even though they are not very useful in this particular submarine application.  However, should I find myself in a night dive, stranded on the bottom, with the rear ballast tank blown off the stern, drunk, incoherent, and unable to ascertain spatial awareness; the data will come in handy so I can inform surface support that I am sitting on the bottom pitched up 45 degrees and need a lift bag attached to the stern.  :)  See...we can justify anything.
>>>>> 
>>>>> 
>>>>> 
>>>>> From: Cliff Redus via Personal_Submersibles <personal_submersibles at psubs.org>
>>>>> To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
>>>>> Sent: Thursday, May 24, 2018 11:15 AM
>>>>> Subject: Re: [PSUBS-MAILIST] DSV Aquatic update
>>>>> 
>>>>> I see depth on your navigation HMI but not altitude.  Are you planning on adding this sensor?  Having run my boat for several years, I find that all data is not equally important.  What I find I check a lot are SOF of air tanks, SOC of batteries, depth, altitude, O2 and CO2 levels, and compass heading.  Other parameters I check less frequently.  Also you use an aircraft roll, pitch and compass heading style indictor which looks very nice.  Having said that, my experience is that K boats have a large spread between CB and CG.  As such my guess is that your indicator will not show much variation in pitch or roll under normal operating conditions but of course your heading will be active. 
>>>>> 
>>>>> Keep updates coming.  I enjoyed video.  Would be nice to have voice over as you walk through buttons and screens on HMI.
>>>>> 
>>>>> Best Regards
>>>>> 
>>>>> Cliff
>>>>> 
>>>>> 
>>>>> 
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>>>>> 
>>>> 
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