From: Brent Hartwig <brenthartwig@hotmail.com>
Reply-To: personal_submersibles@psubs.org
To: <personal_submersibles@psubs.org>
Subject: [PSUBS-MAILIST] Open Discussion's Allowed in PSUB's Mailing List
Date: Wed, 22 Aug 2007 02:10:55 -0700
Jay,
I've heard a number of times in the past how some choose to be blunt with
new comers to the group and/or amateurs in the field of subs. I think one
can be straight forward with important information in a way that doesn't
come off as rude or disrespectful to those that lack or one believes, lacks
there expertise and experience in that area. This group is primarily for,
and always has been for learning and exploring of how to design, build, and
safely operator ones own sub through open discussions and sharing of
information and/or hardware with amateurs and experts alike.
Perhaps there is a need for a new forum for a select group of individuals
that don't wish to deal with teaching and/or reading what amateurs are
talking about, and want only very serious factually accurate post in there
group. To join this group one would need to have done more then 500 dives
in a sub worth more then $100,000, and/or been in the submarine field
professionally for more then ten years, and/or they have a doctorate in a
related field.
I've seen discussions more or less shut down by a type of intimidation, on
subject matter that some were tired of discussing and/or not interesting
in. I think that is wrong for this group, and that if one doesn't want to
read and/or respond to subject matter(s) they are tired of and/or not
interested in, it is very easy to just delete all messages with said
subject matter and/or content. We will hopefully always get new comers into
this group with basic questions and great new insights to old problems, and
they shouldn't be required to read and understand the whole PSUBS archive
before they post a question to the group. I spend a massive amount of my
time researching subs and related data, and I barely have time to read and
try to fully understand the current emails from the list, let alone read
and understand the whole archive. Perhaps I'm slow, and if that's the case
then I'm ok with that. Those are the jeans my parents gave me, and I'm
happy to have what I got.
I once posted a question about whether or not I needed to anneal acrylic,
if I only cut it with a aqua jet cutter. Since I had reason to believe the
aqua jet cutting process wouldn't put any heat stesses on the acrylic that
would need annealing to take care of. I did a PSUB's archive search before
I posted my question. Along with the speculation that my question wouldn't
be answered in a great but slightly dated $200 book, (I hadn't aquired yet)
since I believed aqua jet cutting of acrylics was basicly a new process, I
asked the question. I got the patt answere of that, all acrylic needs to be
annealed after cutting, in such a way I couldn't tell if they really knew
that, with regards to my question, or if they just didn't want to deal with
it. Then they shut the discussion down by intimidation by being an expert
in the group (most don't want to perturb) and stated that the topic was
basicly old and dead.
When I said, " How about an non educated guess. ; )' " that was tough
and cheek Jay.
In my opinion, I'm reasonably well educated and practiced in a fair number
of areas, and I worked very hard to get to where I am today. I have so many
skill sets and interest it's hard to keep on track most days. Almost
everything is of interest to me. Many far more negative people then you,
have tried to get me to hide in a corner because I've chose a very
different path then them selves. You can see the result.
I would guess that for most of us here in this group, this is a passionate
hobby of there's. Hobby's are supposed to be fun and enriching, not
negative things that suck the life out of you.
We have talked about using the KISS (Keep It Simple Stupid) principle for
sub design. I agreed with you that one should do that if at all possible.
How simple is simple? The fact is that most subs in order to have the
capabilities one wants them to have, can't have all aspects of there design
be simple.
Just recently you gave me a link for a book called Simplicity in Design, as
a response to one of my post. Again I ask, how simple is simple? It's all
subjective to ones brain power and understanding of how things work. What
makes art beautiful? It's mostly all in ones head.
During that same period in your post in response to mine, you made it sound
pretty clear that I shouldn't post to this group until I read and
understood the ABS manual and reams of other technical manuals, science
articles, and books relating to sub design and operations. If I and or
others were required to do that, then it would likely be years before we
could post here.
"Instead of ?guessing? all of the time, please do some real research."
I do massive amounts of research almost every day before I send most of my
longer post to the group. But at some point with all the massive amounts of
data out there on the net, one just needs to post a question or two to the
group and see if anyone can, or is willing to give some insight, or even
give a guess, that can help discover the answere.
I'm not interested in perturbing or annoying anyone on this group. I'm here
primarily to learn and share what I've learned.
Since many subs are military or trade secrets for large organizations, many
times we are left guessing why they designed it a certain way. It's a
mystery, and who doesn't love a good mystery. It's like a puzzle that with
enough brains but to task can figure it out or find someone that can.
I think that if the MIR subs have one or more very large drop weights, that
if dropped could make vortex shedding a problem that the rear stabilizer
would be very helpful in dealing with.
When I said I don't know if that is a Kort or Rice nozzle, that was a
prompt for someone that does really know to please speak up and so we could
learn more about the sub.
"I can tell you from an early proposal for building the Mir subs that they
are size constrained for carrying in aircraft holds and the fins on top are
probably a means for shortening the overall length due to deck housing
issues (this is a factor in a number of submersible designs)?but it is pure
speculation on my part."
So why is it you can speculate and I can't? I had reason to believe I had
a couple of possible good reasons they designed the rear stabilizer the way
they did and I was bouncing them off the group for an open discussion to
pool the groups large knowledge base. I don't know how many times
colabortion with others has produced wonderful things in my life and
others. If I had a part of a good idea, one or more people would come along
and fill in the blanks and make it a whole good idea.
"Neophyte PSUBers often take as gospel any information that is found here
on the PSUB list and can lead to misconceptions on their part in the
future?some of which may be dangerous if not down right deadly."
I would expect anyone with the were-with-all to build, and then operate
there own sub wouldn't believe that this "DISCUSSION" groups postings are
all, or even mostly all the gospel truth. Such a person wouldn't likely
able to read and understand enough of what this group is talking about to
hardly get started on there own sub, let allot survive the walk to the
garage.
Regards,
Brent Hartwig
From: bottomgun@mindspring.comTo: personal_submersibles@psubs.orgSubject:
RE: [PSUBS-MAILIST] MIR aft planesDate: Tue, 21 Aug 2007 15:59:28 -0400
Brent,
Instead of ?guessing? all of the time, please do some real research.
Neophyte PSUBers often take as gospel any information that is found here on
the PSUB list and can lead to misconceptions on their part in the
future?some of which may be dangerous if not down right deadly. You will
note that many of us refrain from making replies here unless we have some
expert knowledge to bring. A number of us have to waste a good deal of
time better spent on other endeavors dispelling misinformation that is
either represented as fact or not clearly labeled speculation by a
non-engineer or scientist.
I did not respond to this particular request by Joe as I do not know why
the Russians have used this configuration but I can tell you it is not
because the water is not disturbed yet and vortex shedding is not an issue
here. Both issues are related to speed here and speed is not one of Mir?s
fine points. You can not tell whether it is a Kort nozzle, a Rice nozzle,
or simply an entanglement guard without viewing the cross section of the
nozzle or someone more closely associated with the Mir submersibles making
a response. Due to the small size of most all submersibles, there is
little reserve buoyancy that can be effectively designed in?all of them
have handling issues on the surface. While a lot can be learned from
images and visiting various submersibles, hard calculations along with
weight and trim spreadsheets are necessary prerequisites for a successful
submersible with a long, safe lifespan. How do you know you are not
looking at a given submersible?s weak point or a poor design?
I can tell you from an early proposal for building the Mir subs that they
are size constrained for carrying in aircraft holds and the fins on top are
probably a means for shortening the overall length due to deck housing
issues (this is a factor in a number of submersible designs)?but it is pure
speculation on my part.
A dunce can appear brilliant if he holds his tongue.
Jay K. Jeffries
Andros Is., Bahamas
A skimmer afloat is but a submarine, so poorly built it will not plunge?
From: owner-personal_submersibles@psubs.org
[mailto:owner-personal_submersibles@psubs.org] On Behalf Of Brent
HartwigSent: Tuesday, August 21, 2007 2:39 PMTo:
personal_submersibles@psubs.orgSubject: RE: [PSUBS-MAILIST] MIR aft planes
How about a non educated guess. ; )'Thanks for the link to the pic Joe. I
would "GUESS" that the aft plane is controlled my the pilot directly or by
hydraulics or the like. The swept-back feature is for coolness factor Joe.
Na for that I would say it helps if you lightly hit some thing you'll just
bounce off and keep going instead of braking the aft plane, but more
importantly I would say its for reducing entanglement issues. That is why I
like to have surfaces on my sub rounded over and swept back to some degree,
with no item protruding forward like the weapons systems on the Star Wars
X-wing fighter. On another note since the aft plane is acting like a
planes elevator, having the said aft plane up and out of the way of the
swirling water coming off the subs hull, gives the pilot more control then
if its down and directly behind the sub. This is why allot of ships are
now using forward facing props, that pull instead of push. This is more
efficient since the water hasn't be really disturbed yet and you can get a
better directional bit into it. I would say that the whole stabilizer
assembly also really helps to deal with vortex shedding. But for that I
would use a larger assembly. I like the Kort nozzle on the sub, or is that
a Rice nozzle? From what I understand the Rice nozzle is more efficient. I
wish they would add some soft saddle tanks to the Muir subs, to give them
more freeboard staybility. Allot of people get really sick in them when at
the surface. Watching the Zodiac cowboys try to attach the crane cables to
the subs in rough water is one of the reasons I started designing trimaran
subs. I know that adding tanks to the subs gives them more hydo drag, but
that is another one of these trade-offs we have been talking about.
Regards,Brent Hartwig
> From: joeperkel@hotmail.com> To: personal_submersibles@psubs.org>
Subject: [PSUBS-MAILIST] MIR aft planes> Date: Tue, 21 Aug 2007 12:15:46
+0000> > > Can someone please explain to me the precise function and
mechanics of the > aft planes / stabilizer on the MIR submersibles?> > In
this image, you can see it rotated at an exaggerated angle, which makes >
me wonder if this was done mechanically by the pilot from within, or the >
unit is "free pivoting" for some reason which escapes me.> >
http://www7430.nrlssc.navy.mil/7432/hydrates/images/Muir_1.jpg> > Why then
I also wonder, the extreme sweep-back of these planes? You see this > in
aircraft for aerodynamic purposes in the transonic flight envelope >
(airliners) but, why here? This is repeated in both MIR's as well as the >
proposed Alvin replacement.> > Any info is most appreciated, even an
educated guess.> > > Joe> > > > > >
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