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Re: [PSUBS-MAILIST] External frames
Once again,
Thanks Big Dave and Vance. I will look further into
the ASME codes and their application into what I'm thinking of. Eventually I
will have some concept drawings to show you, but mostly the project is just
restricted to research as painfully, when my computer had to be reset up, I
lost my CAD program, and the disc to reload it is in New
Zealand......
I wasn't going to say much at this early stage, but
at the risk of some skepticism, I'll tell you a little bit about what I'm
thinking of. My last project was a 60ft steel yacht I designed, built and lived
on for 10 years, so this idea, although challenging, I'm sure could be achieved
!
What I would like to build is a look alike
autonomous sub of an Orca about 12M long. Why should Pat have all the fun with
'unusual' sub concepts ! Meant in the best way Pat.
The tail would swing (with sealed attached motors)
in two directions to give up/down and sideways thrust.
The hatch would be flush mounted ahead of the sail
and also be the diver exit with an internal and external hatch. The reasons for
this are, although I would have some kind of shield to protect the opening
from waves when surfaced, which would have to fold or slide up and down, just in
case a wave did inevitably go down, it could be pumped out of the diver
chamber.I have always liked the idea of being able to leave and return from the
sub under the water, and in particular, to be able to free the sub from any
entanglements, which, I feel in the long term will eventually
happen.
The weight can't exceed about 40 tons due to the
limitations of a particular yacht travel lift I want to use.
The sail, would be just like the shape of a normal
Orca fin and contain air intakes, aerials, video camera, lights and be made of
fiber glass.
The dome bow acrylic dome would be shaped to be of
no disturbance to the laminar flow, so would have an internal facing flange, as
I mentioned in an earlier post. The pilot would be situated directly behind
it.
Ballast tanks, four of which would be centrally
located and incorporated into the 'between hulls' location, as also would be the
bottles. I never liked the idea of being sealed in with a large volume of
compressed gas.
Look guys, I would really like to hear your
thoughts and any ideas you can contribute to this. I agree with the what seems
to be a consensus, philosophy of not doing anything too radical and within
proven safety margins. No flywheels Gary and Alex :-)
Carsten has already been very constructively
helpful with ideas and drawings, as busy as he is ! Many thanks
Carsten.
Many times in NZ I've spent many rewarding hours
with dolphins and whales in the water myself. Sometimes, hanging off a rope
while being towed, eyeball to eyeball with a 50ft Brydes whale, hard to beat.
I've whistled a tune to a dolphin while hanging off the bow of my yacht, and the
dolphin whistled it back ! I want some more of these experiences and also to
study our ocean friends.
Many thanks and Regards,
Karl.
----- Original Message -----
Sent: Saturday, August 05, 2000 2:50
AM
Subject: Re: [PSUBS-MAILIST] External
frames
Hello Karl:
Stiffening rings can be
placed on the inside or on the outside of the vessel. The only
difference according to ASME Code (UG 30) is in the attachment of the rings to
the shell in terms of an intermittent weld. For outside rings, the weld should
not be no less than 1/2 the outside circumference on 6" centers. For
inside rings, the weld should be not less than 1/3 the circumference on 6"
centers.
The fillet weld size shall be the smallest of the following:
1/4", the thickness of the vessel wall, or the thickness of the stiffener at
the joint In terms of material for rings, the preference is toward using
rings flame-cut from plate as opposed to rolled material because of possible
gaps between the ring and shell from out-of-round rolled rings. Of
course here they are probably referring to vessels with a big O.D. as they
refer to 1-2" possible gaps. No such problem with our pityful small
vessels(Carsten excluded).
TTYL,
Big Dave
Hi Guys,
In contemplating the practicality of a design
concept I am thinking of, I need to know or be pointed in the right
direction, concerning the pro's & con's of external frames versus
internal.
No doubt, there are some structural
advantages for internal frames, hull welds are under compression versus
tension, and the external frames may need to be heavier for external
application. Maybe even a combination could work. External frames and
internal bulkheads, for example.
My intention is to create maximum internal
space for minimum volume and a double skin to create ballast pockets, bottle
storage and above all else, a streamlined hull, from a simple cylindrical
pressure hull. The outer skin, would be glass fiber.
I'd also like to congratulate Carsten and Dale
on their progress. It is very encouraging to read about and view the
progress.
Thanks also for all the great scrubber info
Paul and the rest.
Regards,
Karl.