Or, just open the valve on top of your
3000 psi scuba tank and try to stop the air from coming out with a 1/8”
wooden plug! (good luck)
-----Original Message-----
From:
owner-personal_submersibles@psubs.org
[mailto:owner-personal_submersibles@psubs.org] On Behalf Of Dan H.
Sent: Tuesday, January 06, 2009
4:30 PM
To:
personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] Soft
ballast venting valve
To test
all you need to do is make up a through port simulation and screw it to the end
of a garden hose to see what it will do at about a hundred feet, depending on
your domestic water pressure.
Holding
the plug in the hole at 10,000 feet would be difficult but not the most
difficult part. That would be getting it in without tearing your skin off
with the water stream.
-----
Original Message -----
Sent: Tuesday, January 06,
2009 11:11 AM
Subject: RE:
[PSUBS-MAILIST] Soft ballast venting valve
It would be interesting to do a test ( on dry land ) with a O ring missing and
see what kind of spray one would get through that .050 gap at various
pressures. It would be easy enough to simulate. Didn't the Germans
have small wedges of wood to plug holes in case of emergency ?
" At
a depth of 10,000 ft the bore of a 1/4"tube bulkhead fitting would need a
plug load of less than 125 lbs to keep seawater out" ( from Man
Beneath the Sea, Penzias and Goodman) ............food for thought.
-----Original Message-----
From:
owner-personal_submersibles@psubs.org
[mailto:owner-personal_submersibles@psubs.org]On
Behalf Of Dan H.
Sent: Tuesday, January 06, 2009
5:22 AM
To:
personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] Soft
ballast venting valve
I agree
with Jim on the clearance, and you'd be surprised how much water can squirt
through only .050 inch clearance. Don't forget, in a P-sub you don't have
many pounds of wiggle room for being to heavy to get back to the surface and
even less wiggle room to get unseated, turned around and contorted into
position to deal with a water leak.
Once I
was submerging in the passenger position with someone else in the pilots seat
of my sub. I was instructing the guy through a dive. He secured the
hatch dogs when I told him, but barely tightened them. When the
hatch seal submerged a thin spray of water wafted down on both of us. It
happened so fast, even with the hatch in less then a foot of water, that
neither of us could react until we were pretty wet. I grabbed for the MBT
blow valves and brought us back up really quick. We only took on about a
quart of water plus what was dripping from our pants. Some of
those drips had a yellowish tint, I might add.
Immediately
after the incident I realized if we submerged any deeper the pressure on the
hatch cover would have sealed the leak, but there was no time to think that
through with water spraying in.
-----
Original Message -----
Sent: Tuesday, January 06,
2009 7:32 AM
Subject: Re:
[PSUBS-MAILIST] Soft ballast venting valve
I agree
with your concept about shaft/ fitting and thats my reason for being very
comfortable with it while Frank is not.
I have
to take exception to your clearance. Mayby it's a typo, but 50 thousanths is
WAY to loose for ANY O ring seal in mu opinion and extrusion is expected.
I will
hace about 5 -10 thousandths. I do this by boring the sleeve slightly
undersized then welding the sleeve in place. After welding ream to size with a
propersized reamer.
I wish
I could get tighter, but doing the reaming freehand that's the best result I
can get.
I am
also using a Block V seal which I feel is better than an oring.
The
idea ame from Gary Sluis.
-----
Original Message -----
Sent: Tuesday, January 06,
2009 12:53 AM
Subject: RE:
[PSUBS-MAILIST] Soft ballast venting valve
When
you figure the diameter of the shaft and the diameter of the shaft fitting,
that the shaft goes into, there is only a difference of like 50 thousandths of
an inch. Even if you forgot to put the O ring in that fitting, it's not
like going to be Niagra falls coming into your boat. You could probably
put some bubble gum on it and the leak would stop. You would be
able to address a problem like that as soon as it occured.
The hydrolics would add too much of an extra thing for me to deal
with. I wonder if there is a way to smooth out those cast fittings
so they could be polished? I will probably put a T into my ballast
vent valve inbetween the valve and the ferro body for HP air. It would be
nice to have a LP air generator for "topping off" the ballast
air so as to float yourself higher on the surface. I seem to remember the
Tang would do that to try and get maximum speed on the surface, they
would run the compressors into the ballast and the exess air coming out the
bottom of the ballast would cut down on the friction against the water.
giving them an extra knot per hour speed.
-----Original Message-----
From:
owner-personal_submersibles@psubs.org
[mailto:owner-personal_submersibles@psubs.org]On
Behalf Of ShellyDalg@aol.com
Sent: Monday, January 05, 2009
6:38 PM
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] Soft
ballast venting valve
Hi Brian. That makes good sense. Save a few bucks and go with what
works. As for matching up the two materials, There's always going to be the
corrosion factor to deal with. Zinc sacrificial anodes will help but not
eliminate the problem. On the plus side, bronze and stainless won't
"gall" when screwed together. I'm using a lot of brass bolts mated to
stainless lock nuts. Although replacement of the brass will be needed sooner
than stainless bolts would, at least I know I'll be able to get them apart
without a big hassle. Some places I'll be using stainless bolts and brass nuts,
because I need the extra shear strength of the stainless, but again, it comes
apart easily after a long time in salt water.
I too am going with the bronze valves. They are pressure rated to 600
psi, are cheap to replace, and when polished they look really good. Very
"Capt. Nemo" like. Also, the highly polished surface corrodes much
slower than the regular cast surface. I've got quite a few of the interior
valves, unions, elbows, nipples, and related bushings and adaptors and when
polished, they look really good. The HP air will be like yours, Swagelock and
stainless tube.
I haven't cut in any through-hulls yet, but those will all be stainless
nipples. Then a bronze ball valve on each one where it enters the sub. Complete
shut-off at every penetration if a problem develops. Even the electrical
through-hulls will be valved off. I want to get all the components mounted
before I start cutting in the nipples. The largest is 2 inch, while the
smallest is 3/8 inch. The main ballast will all be 1 inch. Maybe a little slow
to submerge but I don't expect that to be a problem.
You said you're using rod linkage to operate your valves? Wouldn't a small
hydraulic cylinder work just as well?
When the weather gets a little better, I'll cruise down on my bike for a
visit and a cold beer. Frank D.
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