Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length.

[JosephHuntley]

Hey guys I am working on 2 research vessels the RV Atlantis which operates the Alvin Submersible and its sister ship the Thomas G. Thompson. this project came about from the research engineer of the Thompson interested in a virtual model of the ship. He provided me with some of the drawings for the ship (after some paperwork with the US Navy that owns the vessels) and I have been getting the hull lofted up.
 So far I have the bow half finished (Both ships use the exact same hull the only difference is the transom on the Atlantis) and today started on the aft half. I also have all the frames drawn still have to flesh them out but they are spaced 2 ft apart. I am cadding these ships up at full scale and will be building them at 1/48th scale which is somewhere along the lines of 58 1/2 inches.
 
 I do have a question maybe some of you can help me with and that is I am new to boats after getting away from years of doing planes as some of you may know, and I need info on how to add bow thruster to my ships and also the ships dont use conventional props and rudders but use a system where the shafts of the props come down out of the hull and the entire prop thing rotates for better station keeping. and I am not sure how to achieve this in R/C.
 
 Also if anyone is good with wordpress I could use some help on my website I am website stupid.

[JosephHuntley]

the cool thing about this whole project is the scientists and the ships crews of the vessels are following my website with the progress and i get emails from them on how good it is looking so far and how excited they are to watch the progress while they are out to sea and need something to do with their downlime. Thus I want to make these ships as accurate and detailed as possible that is why i need help on some of the finer engineering of the propulsion

[JosephHuntley]

So tonight got the aft section lofted up and tomorrow will clean it up some but the shapes are very nice just need some more sections for a cleaner looking loft

[Brian60]

Stern drives are known as azimuthing props or drives. Both those and your forward tunnel thrusters can be bought commercially but are not cheap! If nobody else links ill post suppliers later when I get to my computer.

[derekwarner]

Joseph.....

Is the sectional representation along the axis as marked O true in position?

Derek

[Brian60]

Here's a couple to look at...

Azimuth or Z drives...

http://www.hobby-lobby-modellbau.com/onlineshop/index.php/cat/c178_Drives.html

tunnel thrusters...

http://www.hobby-lobby-modellbau.com/onlineshop/index.php/cat/c574_Bow-Thruster.html

Azimuth drives....

https://www.modelbouwshopnederland.nl/en_GB/c-264406/scottel-drive/

Tunnel thrusters.....

https://www.modelbouwshopnederland.nl/c-200649/boegschroeven-raboesch/

[jarvo]

Also have a look at the Raboesch site, they do different sizes of bow thruster and i think the took on the Graupner Z drives


Mark

[JosephHuntley]

thanks looking at the robbe Bow thruster it just looks like its a verticle shaft with a paddle that when turned one way goes one direction and turned the other way reverses that looks like it might be easy enough to fabricate possible.  The azimuth drives look a little more complicated but possibly still able to fabricate if I can find a thread somewhere where someone has fabricated their own. my ships will be 1/48th scale and might be a wee bit expensive to get 4 of them at that scale.

[JosephHuntley]

Joseph.....

Is the sectional representation along the axis as marked O true in position?

Derek

Not sure what you are meaning Derek. The whole hull stations and frames are based off the original factory sheer plans and offset table

[JosephHuntley]

Here is with the bow transparent over the sheer plan

[RST]

No offence and maybe it's a translation thing but you shouldn't get confused with "Z" drives -they're entirely different.  Azimuth etc is the correct term for what you want.

These are "traditional" z drives (sports boat hardware)...

http://www.bauer-modelle.com/49010

..for azimuths Aeronaut in Germany offer some exquisite packages if you can afford it.

[RST]

..................Also "derekwarner_decoy": are you taking pictures with your camera of your PC screen (hence the appawling definition and reflections of you / your camera)? Hope you know theres a "ctrl+print screen" button function which lets you get an image straight-off, no faffing whatsoever?  You seem to know how to mark-up images so eliminating the camera part should be easy-peasy?

[derekwarner]

Joseph.....there is no drama, however in the image shown.......you have depicted the hull in 3D, then superimposed a 2D Elevation view of the superstructure on the axis of the hull [fwd to aft]

The 2D image has no correct representation of depth athwart [port to stdb] of the 1/2 width of the hull

Derek

[PS.....sorry you can see the reflection and some swirly lines and consider them appalling RST  ....Martin has been at me to revise my imaging procedures for years]

[JosephHuntley]

Ok yea the reason you dont see a cross section is because I dont have one. I am using navy drawings and they use a table of offsets to draw the stations. and since I am using the offset table the hull width and shape is 100% accurate so I guess the reason they dont have them sections at least with what they sent me.

Now for those that dont know a TOO or table of offsets gives the X,Y,Z coordinate for each station location at each waterline. it creates points like on a graph from school then you use a spline and play connect the dots or you can enter them into an offset curve file and import it into cad and let the cad program draw them for you. it makes the hull highly accurate. occasionally there may be a slight hiccup here or there but that is usually solved by adding or subtracting 1 inch.

Also for those not in the know 2 things:

1: a station is what is used to give the ship shape. it is what is represented by a body plan or table of offsets. A Frame is the actual framing of the ship. So a station is for drafting and design purposes and used for lofting the frames of the ship.

2:unlike older ships like ships of sail and some others where the frames may vary to create proper room and space which is needed to allow the wood to dry out and not rot during the course of sailing. That isnt needed on a current line of ships most of the frames and stations are equally spaced ie length of ship divided by number of stations or frames wanted. in this case stations are 296" apart and frames 2 ft apart which stays the same the entire length of the ship.

[JosephHuntley]

So tonight I tried doing waterlines to make sure all my frames were correct and I found a problem with the front vs the aft section. seems I mistranslated a couple numbers and so my aft sections are .27" too narrow in the aft and that is at full scale. however it is noticable in the waterlines etc so I will spend another day or two fixing things. I say day or two as I am back to work from 3 days off and so work 2pm to 11pm -6gmt so not tons of time til the weekend. however both halves separate look really good

[Umi_Ryuzuki]

I haven't seen the aft lines yet, are you saying it has a skinny butt?

 

[JosephHuntley]

lol from about 1/4 of the way aft to the aft its a straight line. 315.48460547" half breadth or 26.29' half breadth

[JosephHuntley]

Here is a waterline plan from using the Tables of Offsets should give better idea of the shape

[RST]

OOH, T.O.O's -reminds me of evenings at university dept. drawing lines plans with 6' long batons and heavy pointy irons to hold the curves and manually fair a hull on the draughting film!  Then it was mathematical theory of spline curves.  Autoship CAD made things allot easier!  Looks like you have a good set of info and the means to produce an accurate 3-D model from though so far!  Looks like a great subject.

Rich