|
Hi guys!
Well, it's not a matter of: is PVC better then steel... You see, I have
enough skills as a machinist to build the pod myself in steel at very low cost.
That is why i prefer steel. It's only a personal preference. That said, the real
question I have in my head is, will I crack my batteries or not if i pressure
compensate the pod? Be it in steel, PVC, wood, etc... My opinion is that since
the is an amount of air INSIDE the battery case, I think the case will be
stressed the same as if it was empty. And since it's a square plastic box, the
resistance is not too great.
I may be wrong. And I would love to be wrong. It would be much easyer to
pressure compensate the pod then build it to resist the pressure.
Anybody have a though about that?
Pierre Poulin
Québec Canada
----- Original Message -----
Sent: Tuesday, January 18, 2005 3:44
AM
Subject: Re: [PSUBS-MAILIST] Battery pod.
(question for Dan H.)
Yep.
Bill Akins
----- Original Message -----
Sent: Tuesday, January 18, 2005 11:14
PM
Subject: Re: [PSUBS-MAILIST] Battery
pod. (question for Dan H.)
Hi Pierre;
I'd like to give you some "food for thought" on your decision.
If you are going to pressurize compensate your motors, there's no
real problem to pressurize your battery box as well... it's simply more
volume. The weight of your sub is determined by the size (volume) of
the bubble you're trying to sink.
In my judgement, the PVC is a much simpler solution, widely available,
easy to work with, inexpensive, non-corrosive, strong, lightweight, easily
capable of withstanding minor pressure variations. Simply
put, PVC is ideal for an ambient sub.
If you are going to build big heavy steel battery boxes (tubes?) filled
with batteries and lead, can you jettison them in an emergency? I
would hope so. That's a lot of weight. Steel rusts
anyway... but add oxygen from electrolysis, add salt water, add electrical
potential for galvanic action, the conductivity of steel,
and.... well, I like the plastic idea better for an ambient
sub.
But that's just my opinion.
Stan
In a message dated 1/18/2005 7:50:34 A.M. Eastern Standard Time,
poulin.carrier@videotron.ca writes:
Hi Bill,
Sorry to take so long to respond. I had to
make a decision before i reply. I have choose to go with all steel pod.
One of my friend have access where he work to a rolling machine. So we
will roll the tube and I will use 5/8" steel plate as end caps. I will
also place plates inside the pods and fill the empty places around the
battery with lead so the pod will also serve as weight. To reduce
over-all weight of the sub. Which i want to keep at around 1000 pounds.
the removable end-caps will be similar to what Dan explain except that i
will have 2 bolts and they will thread directly on each side of the
battery in a permanent side plate.
As for the battery, I presume that since my
battery have about 3/4" of air on the top, the plastic case will be under
pressure. And it may crack. I'm by no mean an expert but I'm still not
convinced about air-compensation the battery pod. I'll built a pod that
can bear the total pressure.
Yes i will compensate the motors. I'm using 2
minn-kota endura 30 motors. The only reason to compensate them is because
of the seal. The rest of the motor is capable, I think, to resist much
pressure! I will compensate them from the carbon tube directly. this tube
will stay open inside the cabine of the sub.
Thank you again for your much appreciated
input!
Pierre Poulin
Québec
Canada
|