Erik,
Thanks, that's a good idea about the mock-up. Next I'd need to find the
formulas to determine buoyancy - weight versus air within. If someone could
point me in that direction it would be greatly appreciated.
Regardless how the plan works out ambient or 1 atmosphere, having different
options is appreciated.
With an ambient, doesn't the water level within the sub rise the deeper you
go - as the air gets compressed?
Do you plan on compensating for this - for example: releasing air from
canisters?
Or is your sub designed in such a way that is taken into account?
Do you plan on using battery pods to isolate the batteries from water?
Do you enter the sub from underneath then, while it's in the water?
Thanks again.
Marten
-----Original Message-----
From: owner-personal_submersibles@psubs.org
[mailto:owner-personal_submersibles@psubs.org] On Behalf Of Erik Muller
Sent: Friday, April 30, 2004 8:41 AM
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] Sound Absorption
Marten,
why dont you build a mock-up out of cardboard and find out the smallest
diametre hull that you can comfortably sit in for a few hours? (or longer...
!) Also - Dont knock the 'ambient' option!, They are the same total weight
of course, but because the pressure differential across the hull wall is
much smaller, you can get away with lower-strength (and usually cheaper)
hull materials (im using perspex and fibre glass), which also dodges the
need for owning or borrowing heavy machining equipment. In fact, I dont
think Im planning for a single weld in my machine (except for soldering
components, which hardly counts). I sort of think that ambients are the way
to go for first-timers who dont have much in the way of metal machining
skills like me, though I imagine that might be a contentious thing to say..
!
EM.
Dan H. wrote:
Marten,
My K-350 is 3 feet in diameter and luckily, I'm a little guy, 5'-6".
There
is enough room for me to operate the sub with my head in the conning
tower but it's tight when working on things inside the hull. A hull
3'- 6" in diameter would be better but the trade off is it's gets
heavier to trailer around. You might want to reconsider your five foot
diameter design because of it's weight. Remember it has to be heavy
enough to dive. If your not going to transport it, displacement isn't as
much an option.
Dan H.
----- Original Message -----
From: "Marten Liebster" <mliebster@tbteam.com>
To: <personal_submersibles@psubs.org>
Sent: Thursday, April 29, 2004 10:05 AM
Subject: RE: [PSUBS-MAILIST] Sound Absorption
Steven & Dan,
Thanks for your responses and pointers. My sub is in the concept
stage,
I'm
reviewing different ideas and learning what's doable and not. I'm a
fairly big guy - 6'5" - so I'd like my pressure hull to be at least 5
feet in diameter.
For a living I am a programmer and my experience in fabrication is
purely wood working. So the thought of through hull propulsion is a
bit scary for me. However, having hydraulic connections pass from the
interior to the exterior seems much easier to implement.
As a result, I am planning to use hydraulic propulsion, I do realize
it's not as efficient as an electric motor. This is the reason for my
asking
the
original question, I'll have a pump running all the time. I anticipate
that
with not much to absorb sound and with the shape of the hull, that
would
get
really annoying.
Marten
-----Original Message-----
From: owner-personal_submersibles@psubs.org
[mailto:owner-personal_submersibles@psubs.org] On Behalf Of Dan H.
Sent: Wednesday, April 28, 2004 10:29 PM
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] Sound Absorption
Marten,
I haven't got me sub wet yet but the thrusters are up and running. My
three
thrusters are in pods on the exterior of the hull. Of course I can
hear them in the sub but they're not loud. If you had a hydraulic
pump running all the time I'm sure that would get annoying.
I like the idea of hearing noises through the hull. You can't see
everything around you all the time. Hearing a noisy boat in your
vicinity before you surface is a good thing!
Besides, sound abatement materials against the hull is a place to trap
moisture.
Dan H.
BTW. "Persistence" is now yellow. I finished the paint job last week.
Tomorrow the trailer will be blue.
----- Original Message -----
From: "Marten Liebster" <mliebster@tbteam.com>
To: <personal_submersibles@psubs.org>
Sent: Wednesday, April 28, 2004 2:50 PM
Subject: [PSUBS-MAILIST] Sound Absorption
Hi,
I am in the initial process of designing a psub, my first. The web
site
and
mailing list have to proven to be chock full invaluable information
to
me.
One thing that I haven't seen much about (perhaps I'm searching on
the
wrong
keywords) is that of sound absorption.
I'd imagine that a psub could be a noisy place, with all of the
motors, pumps, hydraulic and other equipment. It seems to me the hull
would
reflect
back the sound waves, it being bare metal in a tube-like shape.
Questions:
Is your psub a noisy place?
Do you use anything on the hull to absorb the sound?
Thanks,
Marten Liebster
A psub newbie