[PSUBS-MAILIST] deep test

Cliff Redus via Personal_Submersibles personal_submersibles at psubs.org
Fri Jan 26 16:55:25 EST 2018


That's true but it would be another long trip from Texas.

Cliff

On Fri, Jan 26, 2018 at 3:00 PM, hank pronk via Personal_Submersibles <
personal_submersibles at psubs.org> wrote:

> Cliff,
> I do have a plan in the event Gamma   flooded.  I would use Elementary
> 3000 to connect a line to Gamma and use my barge with the winch to recover
> it.
> I wouldn't spend much time planning for failure, if it floods, the damage
> is done and there is no rush to retrieve it.  I always take a GPS location
> before I start and record it on paper.  You can return a month later and it
> will still be there.
> Hank
>
>
>
> On Friday, January 26, 2018, 12:06:13 PM MST, Cliff Redus via
> Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>
>
> Great feedback hank.  I really like the procedure where you hang a weight
> below the boat and then get negative by dropping weight on the line
> connected to bow lifting lug and having it slide down to the boat until it
> gets slightly negative.  I like that fact you have one line only so no
> change of fowling and you also have the option of pulling the boat back up
> assuming the boat does not flood.   I also like the idea to eliminated the
> incremental test stops.  I agree, KISS improves chance of success.  Would
> sit off the bottom until PLC triggered MBT blow in say at 1-5 to 2 hours.
> Can mitigate uncontrolled ascent to some degree by programming the PLC to
> stop MBT blow when the depth starts to decrease.  Would still need to have
> the surface boat move out of way during ascent.  I noted your earlier
> comment on bottom not being flat around the Homewood launch site.  We will
> find a location on the lake where the bottom is flat  near the 390-400 foot
> mark.  This will mitigate the issue of the boat sliding to deeper depth.
>
> On any of your unmanned depth qualification dives, did you have a salvage
> plan in place the raise the boat if it flooded?  If so what was it?
>
> Cliff
>
>
>
> On Fri, Jan 26, 2018 at 12:25 PM, hank pronk via Personal_Submersibles <
> personal_submersibles at psubs.org> wrote:
>
> Cliff,
> I have done a few tests unmanned, one with my escape pod to 638 ft and I
> simply had the pod positive buoyant by 50 lbs or so.  I had weights on
> small ropes made ahead of time.  I hooked the ropes to the pod and let the
> weights fall below the pod so the pod did not hit potential rocks.  I just
> kept adding weights till it was about 5 lbs negative and lowered it on a
> 5\16 line.  I went strait down no sops, for 1 hr and hauled it up with the
> rope.
> Gamma was tested to just under 500 feet by letting it sink to the bottom
> non-stop with a 1\4 in inch rope connected to a HP valve.  When I gently
> pull on the rope air is sent to the MBT's and it comes up.  That worked
> very well.
> Elementary was tested unmanned by lowering on a small rope same as the pod.
> In my opinion, one rope is all you can have.  I had problems in the past
> with two ropes.
> Your plan is a bit complicated, things tend to not go as planned on the
> water.  I would suggest to hang a weight under the sub so it does not touch
> down, say 5 to 10 feet.  Also I would just send it down, that 5 min rest is
> of no use because if it is leaking it will happen while travelling down.
>  you will feel the weight increase if it is leaking.
> If the weight gets stuck on the bottom I can cut it.
> I will do a 1,000 foot test in Slocan Lake as soon as the roads are good,
> just to be sure I can retrieve R-300 if it ends up sliding down a slope or
> something.
> Hank
>
> On Friday, January 26, 2018, 10:39:00 AM MST, Cliff Redus via
> Personal_Submersibles <personal_submersibles at psubs. org
> <personal_submersibles at psubs.org>> wrote:
>
>
> 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 <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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