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[portside II]

I am thinking of building a new hull for the schottle drives i have in my tractor tug , the idea is to give me more manoverabillity , eg side-wards thrust etc .
My current hull has the drives placed at the front side by side with a skeg for stability at the rear .

but i was thinking what if i was to put the drives fore and aft but slightly off center with a smaller skeg over them ,

This i think would give me the manoverabillity i require and the stabillity without too much fiddling with the throttles of each drive .
I have seen this type of hull with the drives in opposit corners and done it myself , but there was a problem with control . Now if i had three schottle drives then i could have it set out like this .


daz

[destroyer42]

Hi Portside II,
I have just built a 1/32scale SDM tug with the schottles positioned like on your diagram. However the skegs need to be on the center line and you must have a hole in the skegs for the prop wash. My model works just like the real thing in fact a lot of club members have said its to maneuverable and it would win the tug steering competion to easy.
I try & send you some pictures of mine, there are some on this site & the model tug forum.

Destroyer42

[destroyer42]

Hi Portside II,
The line drawings you have are of a rotor tug it has 3 schottle drives one forward & two aft. If you want an SDM tug (ship Docking Module) then you need to do your tug as explained in my previous mail.
Destroyer42

[Umi_Ryuzuki]

Seems we've shown the diagrams and images of the SDM several times in other threads.
Including when you built this version. Not sure why you want to follow plans now.  

http://www.modelboatmayhem.co.uk/forum/index.php?topic=24519.0

.

The Rotor tugs are neat, but setting up the RC controls would be interesting to say the least.

oh... Rotor tugs are two drives forward and one drive on the stern.

‘Rotor Tug’ uses three fully azimuthing propulsion units, with two located forward in
normal tractor configuration and one aft replacing the normal skeg. The hull form is
of a hard chine design, almost flat bottomed to achieve the best possible water-flow to all three units.
An important feature of the ‘Rotor Tug’ is the control system for all three propulsion units.
Each propulsion unit has its own manual controller, giving the tugmaster individual control of
thrust direction and propeller speed. A fourth 'Masterpilot' controller enables any combination of
units to be controlled in unison. A suitable combination of controls is chosen for the operation in hand.

http://www.motorship.com/__data/assets/image/0007/642355/7-Rotor-Tug-A-RT-100E-underwater-graphic-003.JPG

http://rotortug.com/scripts/rotorTug.php

 

[portside II]

Thank you destroyer / Umi , yes i know about following plans but i like to be different , but you have to experiment well i do .
My idea of putting the skegs off center is that the wash from the props would directable equally
and the oval cut outs would allow more efficient sideways power as the props would not be forcing water onto the skegs .
I could however put the skegs center and the drives of center (as in your mini SDM Umi) but i have a problem that lot's of modelers find with twin drives (or is it just me) ,
but at slow speeds one motor starts up first , on my tractor tug i have the same problem and although i am using electronize esc's and have the ajustment pots if i tune them so they both start at the same time in forwards there is a significant difference in starting in reverse, it must be the motors but a replacement pair will set me back at least £56. for 900's so i have them set mid way for best results.
It's just an idea as we know water acts on models differently to full size tugs/boats .
daz

[Xtian29]

Hello

The EDDY with two azimuthal propellers in line could be very a interesting tug for modeller, nice shape isnt'it ?



http://www.towingline.com/wp-content/uploads/2012/04/nieuws_2012_16.pdf

Xtian

[Umi_Ryuzuki]

Very interesting Xtian.
It took me a second to notice those are two different tugs... or wait, no it's not. 
Running with the forward winch reminds me of the the Ztech tugs.

Here is a similar Robert Allan design using voith drives.

[Xtian29]

Hello Aimé

I was interrested with the Voith in line design but this one is more amphidromic with the sked is in the middle.   I'm interresting to try both design.

Xtian