[PSUBS-MAILIST] Sonar and Hydraulic

[MerlinSub@t-online.de (Carsten Standfuß)]

Hi Pat (and all others with sonder/sonars transducers on their subs) 
- you were long time on diving station ..

What do you thing : I would like to place 4 standard
fishfinder transducer forward my bow soft ballast tank 
in front of the anti-collison bulkhead in different directions.

The transducers himself is completly in the saltwater 
- should I seal the inlet from the transducer to the cable with 
hard epoxy or better with some soft acrylic or silicone ?
Pressure will be equal to 250 m deep ( 820 feet ) and 320 m (1050 feet)
on deep test trials. 

The cable himself is more or less soft so for 
me its looks maybe better with soft sealer ?? 

(A secret request : How deep the NAUTILUS MINISUB was going ?) 

Another question to all members : 

My hydraulic-cylinders for the rudders and valves 
will be outside - for the valves a magnet and a reed contact will show
me a green light for situation - valve is closed - but for the sideruder
and both 
deep fins I need a signal back about the angel the ruder/cylinder has 
during action. How can I do this - watertight and pressuretight ? 

Which outside pressure I can give to an reedcontact ?  Anybody outside
here
with a small preesure-test-chamber and some old reed contacts ? 
Same request for the water level indicator inside the hard tanks .. 

Bow is pre-assambelt, will be blasting and painted
before conected the both main parts.  Stern section has just started. 
Pictures are on the picture-labor - maybe back at the end of the week. 
Don't tell me it is big - it is --  big.. Carsten


Captain Nemo schrieb:
> 
> Dan,
> 
> My first tests in the NAUTILUS MINISUB were conducted in zero visibility
> water, and a fishfinder with an LCD screen provided information about the
> boat's height above the bottom, a visual representation of objects in the
> water column and on the bottom, and so forth.  The unit was inexpensive,
> accurate, and handy to have aboard.  I'm still using it, in fact.
> 
> The transducer came with the unit.  Mounting was easy: the receiver screen
> required a bracket inside the pressure hull; the "fin shaped" transducer was
> mounted outside the P-hull: partially concealed with the business end
> sticking through a hole in the free-flooding bow of the ornamental outer
> fairing.  The only real design concern that came up when placing the
> transducer was making sure the downward projected sonar "cone" was clear of
> the structure of the hull.   Easy, really.
> 
> For the "through hull", I cut and trimmed a hole in the P-hull nose cone;
> welded in a slip-fit female-threaded steel coupler; put a male-threaded
> reducer the inside; routed the receiver-end of the cable in through it, and
> filled the coupler with high-strength hard-drying epoxy.  Inexpensive,
> strong, watertight, and the coupler/reducer assembly gives solid steel
> support that keeps the water pressure from pushing the epoxy plug into the
> P-hull.
> 
> Before installation, I also ground off one of the coupler's end-flanges so
> the inside end would be small enough to pass in through the hole in the
> P-hull, while the shoulders of the outer flange would be larger than the
> hole and abut the outer surface of the hull.  This way, instead of a simple
> (and relatively weak) "tube in a hole", I've got a metal-on-metal support
> that is better able to resist the depth-pressure's tendency to drive the
> gland into the hull from the outside.   This self-supported structure,
> backed up by a generous amount of welding, provides great strength.  Within
> my operating depth limitations, I don't sweat the gland's pressure resistant
> integrity at all.  Something else on my boat will implode long before this
> does, I'm sure.
> 
> If I'd wanted to take the time to make it removable, I could have either
> filled the coupler with something like firm-setting silicone (to make it
> easier to remove than epoxy, and minimize the chances of damaging the cable
> during extraction); or made it in the form of a "packing gland" (put a
> reducer on both ends; route the cable; fill the coupler with a suitable
> shaft-packing material, rubber grommets, or the like, and torque the
> reducers down on the packing until the gland is watertight.)  But I've had
> this "epoxy gland" in my boat for ten years now, and it's been maintenance
> free.
> 
> I also used an epoxy gland for the wires going out to my motor.  When it
> came time to replace the old 24-volt MK-4HP with the new 36-volt MK Riptide
> 101, all I had to do was heat the coupler with my "blue tip wrench".   One
> tug and the old plug popped right out the uncapped end, harness and all.  It
> cost me was a few pennies worth of copper wire, but I'd planned to replace
> that with new stuff anyway.
> 
> However, for things like coaxial cables that are integral parts of
> commercially made transducer units, and might be hard or expensive to
> replace; the removable systems (a packing gland or the like) have some
> advantages at maintenance or replacement time.
> 
> On-going renovations to my boat include 18 exterior lights; a submersible
> speaker for the Public Address system; and a HELLEPHONE underwater
> communication unit so I can talk with my dive support crew (thanks, Phil!).
> All these electronic goodies will require through-hulls for wiring, co-ax
> cables, and such.   Where simple wire is utilized, I'm installing the same
> epoxy glands I used with the fishy-finder.  For the expensive co-ax cables,
> I'm using the more maintenance-friendly means.
> 
> Of course, there's probably better and worse ways of doing it, but this is
> what works for me.
> 
> Hope this helps.
> 
> Pat
> 
>   From: "Dan H." <machine@epix.net>
> To: "PSUBS" <personal_submersibles@psubs.org>
> Sent: Wednesday, April 25, 2001 2:33 AM
> Subject: [PSUBS-MAILIST] Sonar
> 
> >
> > A while back, I was talking with a small sub owner about sonar, and he
> > told me that he uses a modified fish finder and it worked pretty good.
> > I plan to be spending some time in lakes with poor visibility.  Sonar
> > could save a lot of headaches caused by bouncing my head off the
> > viewport after striking submerged objects, or worse!  Looking through
> > some marine catalogues, I see there are quite a variety of sounders
> > available.  Some with CRT and some LCD displays.  Some with a lot of
> > bells and whistles, some quite plain.
> >
> > My sub, a K-350, isn't ready for the water yet, but I need to consider
> > through hulls for the transducer, and choose the proper transducer for
> > the unit I will be buying.
> >
> > Is anyone out there using a device like this?  Some input
> > please.........
> >
> > Thanks, Dan H.
> >
> >
> >
> >