|
Thanks for the advice Vance. All good. I have sooo
much to do it is almost overwhelming. But I will take it a little at a time like
I have been doing. Part of the problem is always knowing exactly what to
do.
How to install something, what kind of fitting,
making sure my knowledge and understanding of the system I am working on is
correct BEFORE I build something. Since I am not an expert or experienced
sub
builder I take it slow. I operate under the old
maxim of "measure twice, cut once".
The building of the air equalized battery pod with
a leak detection system in it, fuses, vent system for charging, some kind of
system for charging without removing the screw in pod cap and
disturbing the O ring, along with the tubing going
from the pod to the motor wherein the tubing will carry the air equalization to
the motor as well will of course be the heart of my project and the most
important.
The canopy and other small things are actually
incidental really. By the way, any suggestions on a method to charge the
batteries WITHOUT removing the screw end cap and disturbing the big O
ring?
I have been thinking of using pvc tubing bent with
a heat gun to form the canopy and then attach plexiglass to the outside of the
tubing. Thinking of making it where the section directly overhead the front
pilot will slide back into larger pvc pipes installed onto the sides of the sub.
Same thing for the rear passenger. Now for the
kicker. Since all this tubing is hollow and all added up together would have
some air buoyancy value if I make it sealed of course, I wonder if I could use
it either totally sealed and
let it remain always buoyant to help keep the sub
upright and counteract the battery pod weight with any attendant ballast in the
battery pod. Or if I might attach a small air line to the pvc canopy tubing and
let it flood and only
inflate it when needed. I could drill a few small
holes in the BOTTOM of the pvc pipes so that any excess air I put in or upon
expansion on surfacing could just spill out. I could have a small valve screwed
into the top of the tubing where
I could open it to allow water to enter the pvc
tubing (won't do that with just a hole in the bottom) and then close it to allow
it to take a shot of air. The front wind/watershield will be fixed to the
sub just like a WW2 fighter plane, and the section overhead the
pilot will slide, and the passengers overhead
piece will slide too and they will not have a fixed portion in front. Since
the sliding portions will not be attached to the sub per se, but will be
held on by their bases having pvc tubes sliding backward into
larger
pvc tubes, I would only consider airing
up the sliding portions, otherwise I would have to have a valve for letting
water in and an air line afixed for the fixed front shield and the sliding
portions too. I know this sounds complicated and I might just not
even
do it, especially since I am not sure how to attach
the plexiglass to the tubing without riviting or screwing it to the tubing which
would be hard to keep water and air tight. It's just an idea.
I was just thinking it is an area of possible air
volume at the very top of the sub that might help with stability and lift as
well. Would you just make it sealed and not bother flooding it, or let it flood
and let the air bladders in the nose and tail
take care of the buoyancy? The canopy will be
pretty light compared to the weight of the battery pod, so even if I let the
canopy pvc tubes flood I think the nose and tail bladders will not allow the sub
to turn over.
Your thoughts?
P.S. Thanks for the info on the LRP's
also..............Is chlorine gas (not hydrogen) explosive?
Kindest Regards,
Bill Akins
----- Original Message -----
Sent: Tuesday, January 25, 2005 11:06
AM
Subject: Re: [PSUBS-MAILIST] Wetsub
carrier water transport systems
Launch and
Retrieval Platform--they were (are?) towed aluminum catamaran rafts with
grating decks and big ballast systems. Two divers piloted it, with the sub on
deck. Take the LRP down to 60 feet or so, release the sub, surface. To go
home, repeat in reverse. Sort of like what you have in mind, only they did the
sub transfer underwater, where there was no wave action. Mucho important when
you are trying to mate 5 tons of submarine to 5 tons of raft. Banging be a bad
thing, I can assure you.
Green gas beeze chlorine, yes. Pretty tough
on the fire fighters, who were hoping like hell that the hydrogen we couldn't
see was going to be nice and vent out of there without spitting Trojan
batteries as projectiles. I've seen a pod go like that (in the shop at Perry)
and brother, let me tell you, it ain't a pretty sight.
Leak detectors
are very simple in theory. It's just a little DC open-circuit deal that closes
when shorted by water in the bilges or wherever and lights the light. Take a
little block of PVC, attach two stiff wires a quarter inch or so apart, then
glue or screw it on the inside pod bottom so the wires just clear the surface
(1/8" to 1/4"). Then run a pair of wires from it, through the pressure vessel
wall, and out to your cockpit. Make a little cannister of PVC or acrylic or
something, as this is a wet sub, so things will stay dry. Inside, power it
through switches with a couple of 9-volt batteries to LEDs or something, and a
buzzer. Don't use the sub's main power system, as you want to know about a
leak whether you are powered up or not. Keep it totally isolated and
independant. Goop everything down so errant splashes and condensation won't
cause any problems, and you're in business. Total cost, with batteries, $17.36
or thereabouts. (Okay, I'm guessing. It might go 20 bucks).
Speaking
of which, how are you protecting the penetrations and electrical system? If
you do have a leak, and a major short, straight cables will toast a hole in
whatever is handy and blow you out of the water. A simple solution is to build
in-line fuses. Size them to maximum draw for the system and cable, then cast
them into PVC tubes using 3M goop or something non-flammable. A major short,
such as you might expect with seawater intrustion, will pop the fuses and
reduce your problem to the pod itself. We may all bow our heads now and pray
that it never happens, but should it come about, at least you'd know what to
run FROM!
As for vents, I'd use SS fittings, maybe a 1/4" going in,
and a 3/8" or 1/2" going out. Put bulkhead shutoffs near or directly into the
pod, and valves up high. Hook a regulator to a gas supply, attach it to the
goes-in valve, start a slow flow (just a little air action will do it) and you
have your vent system. If you plumb it high on the boat, then you could charge
in the water, no problem. Also, have the input line and output lines on
opposite ends of the pod. You could do it with both fittings in one
penetration, just run tubing from the input line (inside the pod) to the
front.
Compensation is another deal. If you were talking about oil, I
could probably help, but I've never used air to do it. It seems to me that the
equalization process is more trouble than it is worth for the pod, which ought
to be strong enough to dive where you expect to dive. Psubs has some really
creative guys who have experience with this, so I'm betting someone will help
you out.
If air compensation causes you problems, then you might want
to consider modifying the motor housing to improve its capabilities. That will
take some machine work. You'd want to cut a proper O-ring groove in the
sections, and root out enough metal around the prop shaft to allow a pump seal
of appropriate size to be installed. It isn't all that complicated a process,
and Dan H. has a whole machine shop up there in Pennsylvania with about four
feet of snow in the parking lot. Send it to him. He hasn't got anything else
to do, anyway-----Right, Dan?
I'm looking forward to seeing this
critter. Couldn't find you on the moki pages, so maybe they haven't posted it
yet. I'll keep an eye out. At present, I've got half a dozen Spanish speaking
roofers banging away at my new shingles, so that's keeping me busy.
Best Regards,
Vance
|