[PSUBS-MAILIST] Gauge for outside viewport?

Mon Sep 21 09:34:15 EDT 2015

Exactly. The valves to blow ballast are outside and operated via
through-hulls.

On Mon, Sep 21, 2015 at 8:57 AM, James Frankland via Personal_Submersibles <
personal_submersibles at psubs.org> wrote:

> >1) I have a bunch of oil filled gauges lying around, but if they are left
> in any position other than with the rubber caps at the top, they leak all
> over the place. The shelf they live on is covered with oil, so I'm just not
> confident they will >keep the oil inside in the field.
>
> Yes, I suppose so.  The ones I have drip.  I thought i'd sprung a minor
> hull leak at first...
>
> >2) Yes, SCUBA tank gauges have a tiny orifice in their hose fittings for
> just that purpose, to prevent a broken instrument from emptying your tank
> too quickly. That is good and I plan to use it on the sub as well. However,
> the problem >still persists that SCUBA gauges can only be taken to under
> 500 feet. I came across tech diver accounts of gauge issues such as the
> plastic faces buckling and pinning the needle, or the whole enclosure
> imploding at about 400 >feet.
>
> oh.  Are you not having the HP lines inside the sub at all?  Controlling
> the air with a through hull?
> Regards
> James
>
> On 21 September 2015 at 13:20, Alec Smyth via Personal_Submersibles <
> personal_submersibles at psubs.org> wrote:
>
>> Hi James,
>>
>> 1) I have a bunch of oil filled gauges lying around, but if they are left
>> in any position other than with the rubber caps at the top, they leak all
>> over the place. The shelf they live on is covered with oil, so I'm just not
>> confident they will keep the oil inside in the field.
>>
>> 2) Yes, SCUBA tank gauges have a tiny orifice in their hose fittings for
>> just that purpose, to prevent a broken instrument from emptying your tank
>> too quickly. That is good and I plan to use it on the sub as well. However,
>> the problem still persists that SCUBA gauges can only be taken to under 500
>> feet. I came across tech diver accounts of gauge issues such as the plastic
>> faces buckling and pinning the needle, or the whole enclosure imploding at
>> about 400 feet.
>>
>>
>> Thanks,
>>
>> Alec
>>
>>
>>
>> On Mon, Sep 21, 2015 at 5:03 AM, James Frankland via
>> Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>>
>>> Hi Alec,
>>>
>>> I have a couple of thoughts.
>>>
>>> 1.  The gauges I have are chemical protected, so they have an oil filled
>>> diaphragm separating the inlet line from the gauge internals.  Then there
>>> is a small vent hole at the top of the gauge.  You could attach a rubber
>>> hose\bladder to this vent hole, top it up with glycerine or whatever the
>>> gauge is filled with and have a fully compensated valve with a bladder.
>>>
>>> 2.  How about using just a normal scuba gauge which will probably be
>>> perfectly fine.  But, just make a small adapter that screws onto the gauge
>>> and has only a tiny little orifice to allow the input air.  That way if the
>>> gauge did ever fail, it would only bleed out air slowly and you'd have time
>>> to blow tanks.  If you are using a scuba 1st stage and piping from the HP
>>> port (I assume your not and are plumbing straight into tanks) then the
>>> scuba HP already has this small hole for the same reason.
>>>
>>> Also, it would be easy enough to test a gauge.   Find somewhere deep
>>> enough and take a fishing rod and a packed lunch!
>>>
>>> Im fairly sure Emile has external gauges on his sub and its a 200m
>>> diver.  He could maybe advise?
>>>
>>> Just a thought.
>>> Kind Regards
>>> James
>>>
>>>
>>>
>>> On 21 September 2015 at 06:51, Brian Cox via Personal_Submersibles <
>>> personal_submersibles at psubs.org> wrote:
>>>
>>>> Hi Alec,    New sub ?  I must have missed that !    do you have any
>>>> details?    BTW, I received that big gage !  It's huge !  I hope I can get
>>>> it in through the hatch !   As it is designed for sea water I assume all I
>>>> have to do is plumb it in, will salt water getting into the tubing cause
>>>> any problems?
>>>>
>>>> Brian
>>>>
>>>> --- personal_submersibles at psubs.org wrote:
>>>>
>>>> From: Alec Smyth via Personal_Submersibles <
>>>> personal_submersibles at psubs.org>
>>>> To: Personal Submersibles General Discussion <
>>>> personal_submersibles at psubs.org>
>>>> Subject: [PSUBS-MAILIST] Gauge for outside viewport?
>>>> Date: Sun, 20 Sep 2015 23:03:02 -0400
>>>>
>>>> I have an interesting thing to think about and wondered if any of the
>>>> PSUBS brain trust might have a suggestion.
>>>>
>>>> One of the simplifications on my new sub is that all HP air lines are
>>>> external, aside from the BIBS (which is normally shut off anyway). Thus,
>>>> I'm looking for a 3,000-4,000 psi gauge to mount outside a viewport, like
>>>> in the Pisces photo that I'll paste below. In case my paste doesn't come
>>>> through, it is the one at the top of the following article:
>>>> http://www.nytimes.com/2015/09/15/science/piloted-deep-sea-research-is-bottoming-out.html?_r=1
>>>>
>>>> The first thing that came to mind was to use a SCUBA submersible
>>>> pressure gauge, but the problem is these are normally 1 atm dry enclosures
>>>> of limited depth rating. There is generally little information posted about
>>>> how deep they'll go, but what I did find was mentioned 260 feet for the
>>>> plastic ones and 490 feet for the brass variety. This is a 1,000 foot sub.
>>>>
>>>> The second idea was to use oil filled gauges intended for above-water
>>>> use. But these generally have considerable bubbles in the oil, are not very
>>>> good at keeping the oil inside, and have other hardware not intended to
>>>> live long in sea water.
>>>>
>>>> Any suggestions would be most welcome!
>>>>
>>>>
>>>> Thanks,
>>>>
>>>> Alec
>>>>
>>>> [image: Inline image 1]
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