Joe,
I agree that a dedicated bow thruster is likely the best option, and likely cheaper and easier as well. You could add a little length to the bow forward the X thruster arrangement and up high enough not to get in the way of your front view port. I know that would make the NR-2 look a little less like the NR-1, but it would be more functional. I guess you could say it's a balancing act. Design work usually is a balancing act between function, styling, cost, and weight. I enjoy trying to design things that are usually pretty expensive with good, yet less expensive materials and/or processes.
Of course having another thrust gives you some more drag from the tubes like Frank said, but the trailing edge of the tube can be rounded over like I've seen on a number of bow thruster in boats. I was planning on doing this on the model I made up for you, but decided it would just clutter the design I was trying to get across. I'll work up a model of it today if I get a chance.
Brent
From: "Joseph Perkel" <joeperkel@hotmail.com>
Reply-To: personal_submersibles@psubs.org
To: personal_submersibles@psubs.org
Subject: RE: [PSUBS-MAILIST] X Thruster arrangement
Date: Mon, 23 Jul 2007 12:05:48 +0000
************************************************************************ ************************************************************************ ************************************************************************ The personal submersibles mailing list complies with the US Federal CAN-SPAM Act of 2003. Your email address appears in our database because either you, or someone you know, requested you receive messages from our organization. If you want to be removed from this mailing list simply click on the link below or send a blank email message to: removeme-personal_submersibles@psubs.org Removal of your email address from this mailing list occurs by an automated process and should be complete within five minutes of our server receiving your request. PSUBS.ORG PO Box 53 Weare, NH 03281 603-529-1100 ************************************************************************ ************************************************************************ ************************************************************************Jay,
No, I didn't forget, I've been mulling it over in my mind for a while.
As I told James, things that I invent, or have not seen in actual use, are considered un-viable until proven otherwise.
You're just reflecting my "gut" feeling here anyway, I don't know "why" either. Something about the behavior of fluids in flow bothers me in that I'm somehow likely to lose functionality with this scheme.
NR-2's circumference is too small to allow the X thruster tops to be below waterline. Increasing the angle is counterproductive. Rudder authority, will only be good in open water transits above 2 kts, so I must have full thruster control on the surface for dockside maneuverability!
Options then.....
1) Increase circumference accordingly? Impractical!
2) Dedicated bow thruster. Only guaranteed viable option.
Thanks
Joe
I see a couple of other responses in my inbox, will get to them when I can, suddenly got a bit busy.
From: "Jay K. Jeffries" <bottomgun@mindspring.com>
Reply-To: personal_submersibles@psubs.org
To: <personal_submersibles@psubs.org>
Subject: RE: [PSUBS-MAILIST] Some thoughts on construction (I'm new so my research is not
Date: Sun, 22 Jul 2007 18:24:46 -0400
Joe,
Glad to see that you have come back to this issue, thought you had missed the point. It is my feeling (don?t have anything off the top of my head to substantiate it) that your alternate flow route is a bad idea. For the size of your sub, the separation of your rear twin thrusters should get you some turning motion when they are run in alternate directions. Also remember to get left- and right-turning props so that torque issues are nullified.
R/J2
Respectfully,
Jay K. Jeffries
Andros Is., Bahamas
A skimmer afloat is but a submarine, so poorly built it will not plunge.
-----Original Message-----
From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] On Behalf Of Joseph Perkel
Sent: Saturday, July 21, 2007 11:33 PM
To: personal_submersibles@psubs.org
Subject: RE: [PSUBS-MAILIST] Some thoughts on construction (I'm new so my research is not
Jay,
I had not thought of that either, that is yet...another nugget in the pan!
:)
Now that the subject of the X configuration has been brought up, I have been
bothered about the solution to an issue you once mentioned regarding
surfaced use of a bow thruster in this X, when the opening is above the
waterline.
I've got enough thrusters already, so I really don't want a dedicated
surface lateral but, I sure do need the capability, particularly in tight
marinas, NR-2 will not answer rudder below 2 kts, and I am not too sure yet
about what kind of twisting moment I can expect from the mains in opposition
as they are spaced fairly close.
So I'd like to "float" an idea which may or may not be viable regarding
"feed water" to the thrusters while on the surface.......
http://www.frappr.com/?a=viewphoto&id=269116&pid=7075983&myphotos=1
In any case, there is a problem with surfaced maneuvering, that needs to be
resolved somehow.
Joe
>From: "Jay K. Jeffries" <bottomgun@mindspring.com>
>Reply-To: personal_submersibles@psubs.org
>To: <personal_submersibles@psubs.org>
>Subject: RE: [PSUBS-MAILIST] Some thoughts on construction (I'm new so my
>research is not that thorough)
>Date: Sat, 21 Jul 2007 19:37:58 -0400
>
>Joe,
>
>A further reason for this configuration is that a vertical thruster will
>either suck in mud or stir up the bottom directly in your vision path.
>
>R/Jay
>
>
>
>Respectfully,
>
>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 Joseph Perkel
>Sent: Saturday, July 21, 2007 7:12 PM
>To: personal_submersibles@psubs.org
>Subject: Re: [PSUBS-MAILIST] Some thoughts on construction (I'm new so my
>research is not that thorough)
>
>
>
>James,
>
>The software is Rhinomarine, (rhino3d.com).
>
>No propane tank,....same as K boats, rolled ASTM 516 steel.
>
>Length is 27' overall, pressure hull diameter 42", weight 11,500 lbs, give
>or take...Accurate weight and balance table yet to be done, I will do this
>after I hash out the final concept. The general specifications of PC-5C, is
>the model. http://busby.psubs.org/html/page-176.html
>
>".....With the current thruster angles....the controls should be
>microcontroller based......"
>
>Ah, yes...the thrusters! :) , and I just learned something from you...more
>on that in a moment. Why the 45 degree orientation you ask?.....several
>(not
>yet chiseled in granite), reasons.
>
>1- I need that orientation up forward, if I hope to have any kind of
>forward
>view-port. As it is, the design requires significant camera coverage.
>
>2- This orientation with proper controllers as you note, can and has been
>successfully used in opposition and, in concert for spectacular
>maneuverability, up / down, left / right. Also, this boat will be heavy so,
>the thrusters in opposition to spin her about the vertical axis in her own
>Length, with a snappy response......can only be a plus.
>
>3- The last reason, is mimicking the NR-1 in as many ways possible.
>
>"......This is provided the shaft drag (seals) on each motor are relatively
>close......."
>
>Now this is the little nugget I just got from you. Minute differences in
>shaft seal drag and, how that might effect these little guys controller
>wise, did not occur to me. It just so happens, that with my newly planned
>home machine shop, that I recently decided the four maneuvering thrusters
>would be using magnetic couplers. The two main motors aft, are likely to
>remain shafts. All of these, thrusters and the main motors, will be built
>before the sub is.
>
>I had decided that six rotating shafts, is asking too much from the odds
>maker. But now that you mentioned that, I suspect the magnetic couplers
>should be in a better position to be clones of one another.
>
>Thanks James, may I suggest that you post links for appropriate suppliers
>regarding motor controller electronics on the PSUB web site.
>
>Joe
>
>
>
>
>
> _____
>
>
>From: "Lil Brother LLC" <lil_brother_llc@bellsouth.net>
>Reply-To: personal_submersibles@psubs.org
>To: <personal_submersibles@psubs.org>
>Subject: Re: [PSUBS-MAILIST] Some thoughts on construction (I'm new so my
>research is not that thorough)
>Date: Sat, 21 Jul 2007 14:52:30 -0500
>
>Joe,
>
>
>
>Wow....those are great design elements......something like I was
>thinking....but with a double stepped sail.
>
>
>
>Could I ask what software you used to do the drawings........
>
>
>
>Thanks for the websites....I know there is much reading to be done. That is
>the reason I put in the header my research was not thorough.
>
>
>
>I noticed your design seems to revolve around a propane tank. I think that
>is a great idea....
>
>
>
>How large will the finished design be?
>
>
>
>I will help in any way that I can. The problem with
>electronics......sometimes it takes more than one try to get what you are
>looking for. The first try may work....but it hardly ever works exactly
>like
>you want.(My experience)
>
>
>
>I do have a concern about you design. (Please remember I'm not versed with
>much submarine knowledge) I'm worried about your thruster angles. To use
>the
>thrusters efficiently they would have to be pretty well matched to do a
>coordinated hover turn. (jump from sea floor spin 180 degree and set back
>down) I don't think it is a danger, just could be very frustrating. Can I
>ask why you didn't orient them vertically and horizontally? Or why they are
>not at more of a vertical angle?
>
>
>
>With the current thruster angles....the controls should be microcontroller
>based. It would be able to balance the thrust between the 4 much faster and
>more even than you could manually.This is provided the shaft drag (seals)
>on
>each motor are relatively close.
>
>
>
>
>
>
>
>
>
>
>
>James Long
>Owner/Designer
>Lil Brother LLC (Instrument Division)
>
>----- Original Message -----
>
>From: Joseph Perkel <mailto:joeperkel@hotmail.com>
>
>To: personal_submersibles@psubs.org
>
>Sent: Saturday, July 21, 2007 8:03 AM
>
>Subject: RE: [PSUBS-MAILIST] Some thoughts on construction (I'm new so my
>research is not that thorough)
>
>
>
>James,
>
>".... I know totally encapsulating( mostly.....the top hatch could never be
>totally surrounded) the crew compartment within a ballast area...."
>
>This is one of several viable design considerations for soft tanks as
>specified by the text "Concepts in Submarine Design", (highly recommended).
>It also happens to be my choice for my own
>design...http://www.frappr.com/?a=viewphoto&id=269116&pid=7063561
>
>My suggestion for someone new, is to read...read...read and then...read
>again. Did I mention read! :)
>
>Besides the online Busby manual on the PSUBS web site, I highly recommend
>and have found a gold mine of information in the NAVPERS fleet boat
>manuals...http://www.maritime.org/fleetsub/index.htm
>
>As you are an electronics expert, perhaps I may ask you a thing or two
>regarding systems integration when the time comes...not quite yet as I am
>far from it at this point.
>
>Joe
>
>
> _____
>
>
>From: "Lil Brother LLC" <lil_brother_llc@bellsouth.net>
>Reply-To: personal_submersibles@psubs.org
>To: <personal_submersibles@psubs.org>
>Subject: [PSUBS-MAILIST] Some thoughts on construction (I'm new so my
>research is not that thorough)
>Date: Fri, 20 Jul 2007 17:05:24 -0500
> >First I would like to thank everyone for a warm welcome. It is nice
> >to see a group of people that openly accepts the new guy to the
> >group.
> >
> >I have a question or two that can be broken up into various
> >departments:
> >
> >1. If the ballast tanks were to totally surround the crew
> >compartment, could the ballast area be used structurally?
> >
> > I mean if the air were purged, then the ballast area totally
> >sealed (with valves). Would this enhance the structure to help with
> >the pressure at depth?
> >
> > I figure since this area would be totally filled with water
> >(which doesn't compress easily) it would add pressure resistance of
> >the hull. (I'm only guessing at this......so anyone could point out
> >the error in my view)
> >
> > I know totally encapsulating( mostly.....the top hatch could
> >never be totally surrounded) the crew compartment within a ballast
> >area would be a major pain, and would be hard to up keep over a long
> > period of time, but it may be worth the while if the design is
> >possible.
> >
> >2. I've noticed a very strange item on the X300( nice fiberglass
> >single place, dolphin shaped sub) aft end. I'm very curious what the
> >item is. I would also like to know what type of propulsion the sub
> >uses.
> >
> >3. Are there any electronic valves out there that are pressure rated
> >for our uses. I would like some companies to checkout to see if I
> >can use them for ballast control.
> >
> >4. What is the typical way of actuating bow and stern control
> >planes?
> >
> >Any other things you would like to point out.....would be
> >appreciated. I do not have any materials to read regarding the
> >design and construction of a sub. My area is very rural and the
> >library is much to be desired.
> >
> >
> >James Long
> >Owner/Designer
> >Lil Brother LLC (Instrument Division)
> >
> >
> >
> >
> >
> >************************************************************************
> >************************************************************************
> >************************************************************************
> >The personal submersibles mailing list complies with the US Federal
> >CAN-SPAM Act of 2003. Your email address appears in our database
> >because either you, or someone you know, requested you receive
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> >from our organization.
> >
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> >Removal of your email address from this mailing list occurs by an
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> >603-529-1100
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> >
>
>************************************************************************
>************************************************************************
>************************************************************************
>The
>personal submersibles mailing list complies with the US Federal CAN-SPAM
>Act
>of 2003. Your email address appears in our database because either you, or
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>The
>personal submersibles mailing list complies with the US Federal CAN-SPAM
>Act
>of 2003. Your email address appears in our database because either you, or
>someone you know, requested you receive messages from our organization. If
>you want to be removed from this mailing list simply click on the link
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CAN-SPAM Act of 2003. Your email address appears in our database
because either you, or someone you know, requested you receive messages
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If you want to be removed from this mailing list simply click on the
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