Re: [PSUBS-MAILIST] Sonar and Hydraulic

["John Pier" <caribsub@coqui.net>]

I use on the Seahorse subs a scanning sonar, looking forward, 600 Ft range
and a downward ping for distance of sea floor.
The 4 " screen displays a radar type image where reefs, trenches, obstacles
and fishes are clearly visible.
The transducer is outside, it s a solid rubber block, i don t know max depth
but up to 140 Ft it is fine. I made the transducer retractable inside the
hull should the bottom , an obstacle or the trailer would hit it.
cost about $600
Herve

----- Original Message -----
From: Carsten Standfuß <MerlinSub@t-online.de>
To: <personal_submersibles@psubs.org>
Sent: Wednesday, April 25, 2001 4:02 PM
Subject: [PSUBS-MAILIST] Sonar and Hydraulic


> 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.
> > >
> > >
> > >
> > >
>
>
>