Re: [PSUBS-MAILIST] Radical Idea

[BluWtrSailr@aol.com]

In a message dated 3/30/02 9:39:58 AM EST, machine@epix.net writes:

<< but I'm imagining two basic boat hulls
 one flipped over the top of the other as a mirror image.  Am I at least 
close?
 Sorry, but you lost me totally with the self draining part.  I understand 
how it
 works in surface craft.   Are you proposing the same for your sub?
 Are you designing your sub as an ambient pressure sub or a one atmosphere 
sub?
 Wet or dry sub?  You mentioned compressor top side but I'm not sure why. >>

First let me say that I am grateful for all the responses.  No..it is not an 
inverted design, I'm thinking a pod floating and the sub down below both 
seperate.  It will be a 1atm sub with snorkel system.  The self draining 
cockpit will work just as a surface craft but a lot quicker so it drains as 
it surfaces.

<Are you dumping emergency ballast?  If your hanging on a
cable you have to be negative buoyant.  Even if you holding yourself down with
thrusters, they usually don't have to power to bring you back up if your 
ballast
tanks are totally flooded.  I'm probably missing something here too.
Since your using cables you might try to design something to keep them from
hanging slack so they don't foul your thrusters.  At thirty feet, you can 
always
bail out if you had to, but why not design to avoid the mess.
Are you using your floating pod to double as an over the road trailer too?  
That
has real appeal for a lake sub and should be doable.>

Yes, I' am going to dump emergency ballast, it will be negative buoyant but 
it does not mean that I cannot maintain neutral or surface with thrusters and 
ballast, only that the safety of 30 feet will never be exceeded.  No, I 
didn't think about the pod doubling as a trailer...but I really like this 
idea and will definitely threaten to use your idea.

<Do you have a plan in mind yet?>

Yes!  Actually, because it is low tech, I will be doing some field tests to 
establish the minimum rear thrust on the pod and the minimum forward thrust 
on the sub to maintain way on, and, I will probably calculate a chart to use 
for different speeds at different thrusts, in both forward and reverse 
directions.

<If you design your pod so your sub is within it while surfaced, you can keep 
you
motorcycle engine topside.   Use the pod to contain your sub and also to lift 
it
high enough out of the water so you can open a hatch to get out with out 
getting
swamped.  Your topside pod should be more of a raft with a hole in it rather 
than
a trailer to your sub.  Pilot the pod to your diving destination with a simple
outboard motor.  No need to have a motorcycle engine other than for a
compressor.  You might rethink the compressor also.  Scuba tanks go a long way
and far less complications.>

Holy mackerel, you are a true genius in laymans clothing.   Excellent 
idea..ofcourse, I have no choice to use it because it would eliminate having 
to trailer the pod, but now I will have to figure out how to set up the 
winching and cabling system elsewhere instead of the centerline of the pod.

<You can't glue the surfaces
together and than  do any welding on them because you will cook the glue bond.
Two layers of material, one laid flat against the other, are never the 
strength
of one solid piece if there is no lateral bond.  Think of a leaf spring on an
truck.  You would get much better strength out of one material thickness.  
Yes,
it is harder to bend thick material than many thin sheets, even if you compare
bending the thin sheets all at the same time.  Exactly my point!
Also, there's the rust factor.  No matter how you try, water will find it's 
way
between sheets of steel.>

Nope, no glue, all edges will be welded to create one solid piece, and the 
pieces will then be glued to the grooves, so it will be impossible for water 
to enter between the layers.  



Actually, If I'm to laminate, I need the grooves to hold the end of the 
sheets inside while creating the desired shape and maintaining it while 
welding.  I also thought of this idea because pressure will be forced towards 
the center which causes the stress to spread out over the longitudinal bars

<One last thought, remember, if you design is a dry sub, one atmosphere, you
should to be designing a collapse depth of near eighty feet to dive it at
thirty.  You'll want to test the hull unmanned to at least fifty feet.  If 
your
squeamish as I am, maybe more.  Design your sub so you can stay calm watching 
it
disappear into the deep blue for it's unmanned test while your thinking of all
the time and money you have hanging on the end of the line.>

I'm unclear as to how to solve for collapse depth and at which depth to test, 
but one thing is for sure,,,a thorough cleansing of human waste will be 
needed subsequent to watching the sub begin to ascend and will probably 
continue until it surfaces.  I think that this will probably be a very tense 
moment, however long, or converesely, short it lasts.

Thank's thank's...I will look into everything.

Charles