RE: [PSUBS-MAILIST] Sound Absorption

["Marten Liebster" <mliebster@tbteam.com>]

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
>
>