[PSUBS-MAILIST] deep test

Fri Jan 26 14:42:47 EST 2018

Good points Alan.  Will end up drafting a detailed procedure. Thanks for
the feedback.  Would not be nice to have the boat flood and then pull then
subject the tender to a 4400 lb anchor!

Cliff

On Fri, Jan 26, 2018 at 1:33 PM, Alan via Personal_Submersibles <
personal_submersibles at psubs.org> wrote:

> Cliff,
> a couple of extra thoughts are a gps system for keeping the support
> boat over the test spot. If a wind came up & moved the boat toward a
> shallower depth you could foul the rope.
> Also a support boat with a winch; just an anchor winch would be helpful.
> At 4000lb negative is she flooded, you would need a contingency plan
> that considered the effect on the support boat if the test rope was
> attached.
> Cheers Alan
>
>
> Sent from my iPad
>
> On 27/01/2018, at 7:41 AM, Cliff Redus via Personal_Submersibles <
> personal_submersibles at psubs.org> wrote:
>
> Thanks Al for the info.  A am aware of Alec's test apparatus.  I can do
> essentially the same thing with my PLC.  I would just have to put a little
> ladder logic in for the test that has a timer that opens the solenoid valve
> that blow my MBT.  I want to hear what has worked for others then I will
> modify the procedure.  You commented that you guys had no formal backup
> plan if Snoopy flooded, what about with Persistence, did you have formal
> plan to recover the boat if it flooded and if so what was it?
>
> Cliff
>
>
> On Fri, Jan 26, 2018 at 12:22 PM, Al Secor via Personal_Submersibles <
> personal_submersibles at psubs.org> wrote:
>
>> Cliff,
>>
>> The other unmanned test where the lines got fouled that you are referring
>> to is when I helped Dan H. test Persistence in Seneca Lake.  The way we
>> recovered was
>> Dan and I brute force hauled the sub up by the line pulling had over
>> hand.  At the time, the weather had picked up and there were pretty good
>> waves on the lake
>> making it pretty challenging with everyone else on the boat getting sea
>> sick.
>>
>> I also helped Alec but he had a pretty neat method where he had an
>> electric timer with solenoid valve which blew ballast at the end of the
>> test.  Fortunately it worked like a dream since I don't believe he had a
>> backup plan in case it failed.
>>
>> Al Secor
>>
>>
>> ------------------------------
>> *From:* Cliff Redus via Personal_Submersibles <
>> personal_submersibles at psubs.org>
>> *To:* Personal Submersibles General Discussion <
>> personal_submersibles at psubs.org>
>> *Sent:* Friday, January 26, 2018 12:39 PM
>> *Subject:* Re: [PSUBS-MAILIST] deep test
>>
>> Hank, I have not worked the details yet but I can give you my tentative
>> thoughts.  The location of the test will be Lake Tahoe in Ca on June 25-29,
>> 2018 as you know, with Homewood Ca. as the base.  We will use a tender
>> vessel that will setup over the dive site.  We will find a dive site with a
>> bottom at a little past my max test depth of 375 ft.  I plan on ballasting
>> up the boat so that when the MBT are flooded, the boat is about 20 lbs
>> positive.  I will then attach a 400 ft line that has been marked every 10ft
>>  to the bow lifting lug. When we are ready to do the test and you are ready
>> to submerge Gamma, I will add 25 lbs of lead ballast wrapped up in rubber
>> so it will not damage the boat on a line just aft of the viewport.  This
>> location is just above the CG/CB of the boat.  Boat crew will slowly lower
>> the boat until reaches the first depth station at 75 ft. We will stay on
>> station for 5 minutes.  At any point if the bow line starts to add weight,
>> we will abort the test and pull the boat up immediately. Divers will be in
>> water and follow boat to  75ft stop. Gamma will be monitoring the dive all
>> the way and down and back up.  Also, if Craig Busell can make this date,
>> his Phantom T4 ROV will also be monitoring/logging the dive and giving us
>> real time video feed on the surface which would be great.  The boat will
>> then be lowered in 20% of test depth increments (75ft).  At each depth stop
>> we will stay on station for 5 minutes.  If all looks good we will proceed
>> to the maximum test depth of 375ft where we will stay for 30 minutes. We
>> will then pull the 20 lb weight off the boat which should change the boat
>> into a positive buoyant state.  Gamma and the Phantom will monitor the
>> decent and ascent.  As a back up, the PLC on the boat will be programmed to
>> automatically blow MBT at 2 hours from the start of the dive.  The PLC on
>> the R300 will have logging turned on so at the end of the dive I can
>> retrieve the memory card to interrogate all boat systems during the test
>> dive.  I will look into a number of backup steps including seeing if
>> a local dive shop has a diver with a rebreather that would be willing to
>> dive to 375 ft.  We will make sure we have some kind of harness on the bow
>> lifting lug that gamma can attach to in case we need her to lift the boat.
>> If the boat floods, the weight will be 4400 lbs in the water so will need
>> to see if can  locate a lifting bag large enough to lift the boat in a
>> salvage mode.  We would not bring the lifting bag to the site but just know
>> where to get one if the test fails.  The maximum depth the boat has been to
>> is 160 ft last year.  If the unmanned test is successful, and surface
>> inspection reveals no surprises, then I will take the boat down to 300 ft
>> to establish the maximum operating depth of the boat.
>>
>> For those of you that have gone through this type of unmanned test
>> before, I would welcome feedback. What worked for you and what you would do
>> differently.  I can't remember which boat but I remember one psub unmanned
>> test dive using a similar methodology in which the two line got wrapped up
>> and fowled. Alec, was this you with Snoopy?  I don't remember how they
>> recovered.  I remember the test was successful.  I am not to worried about
>> the test as the crush depth is 1100 ft (in theory!)
>>
>> Still lots of details to sort out.
>>
>> I know you tested Elementary 300 pressure hull in a pressure vessel but
>> have you done the unmanned test on her?  Also after rebuilding Nekton
>> Gamma, have you done an unmanned test of her?  If so how did you do it?
>>
>> Cliff
>>
>> On Thu, Jan 25, 2018 at 6:40 PM, hank pronk via Personal_Submersibles <
>> personal_submersibles at psubs.org> wrote:
>>
>> Cliff,
>> How are you planning to lower R-300 and how are you retrieving it?
>> Hank
>>
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