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Old Jan 04, 2008, 07:50 PM
Yacht Captain
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Canada, BC, North Vancouver
Joined Oct 2007
322 Posts
Build Log
Project Gatika, Modern Voith Tug

After musing over weather to post here or not I decided it would be good for the model (can't get away with "close enough" with you all watching) to go ahead and start a new thread for my first scratch build.
I followed the link from Umi, thanks, for the Gatika and googled for more pictures where I found sister ships that did not have those big exhaust stacks. I much prefered the look of the Sertosa Ventiseis and her sister Sertosa Ventiocho and decided to build based on them. The hull shape and superstructure (ex exhaust stacks) are the same and only a little re-design was required for the monitors and feed pipes.
Boy does it take a long time to reduce the lines for hull plateing and get them cut and trimmed ready for the build board. Pictures attached show where I am at so far. The idea is to plate the frames with balsa, epoxy laminate outside, remove from build board and epoxy laminate inside then frames and bulkheads. The fancy name for this is a balsa core FRP composite hull. Very strong with minimum frameing required. I will use ply instead of balsa in the area of the drives.
The deck will overlap the hull with the joint hidden by the fendering so that total access to the interior is possible. I find the hatches on my Tito come of regularly and would love to have better access.
The mooring bits will be threaded and screw down onto studding to hold the deck tight to the seal.
Look forward to your comments and advice.

Nigel
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Last edited by yacht boy; Jan 10, 2008 at 06:28 PM.
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Old Jan 05, 2008, 08:00 AM
r/c ships and workboats
bellingham, wa
Joined May 2006
4,447 Posts
Looks good! Going to be a nice build. Noticed the skeg in the framing process, is it going to be left as a flat skeg or as you progress are you going to make it hydrodaynamic (shaped)?
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Old Jan 05, 2008, 11:39 AM
Yacht Captain
yacht boy's Avatar
Canada, BC, North Vancouver
Joined Oct 2007
322 Posts
Kieth,
Funny you should mention that.
This is what I was doing last night.
It is easier to sand and fair a flat surface while the sanding block can overlap. Once the hull is plated I would be sanding in a corner, much more dificult.
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Old Jan 05, 2008, 11:45 AM
Sea Dragon-Lover
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PDX, OR
Joined Dec 2002
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Those are good looking boats, and a good looking set of frames.

Will it be getting wet at Bellevue, Washington in June?
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Old Jan 05, 2008, 12:04 PM
Yacht Captain
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Canada, BC, North Vancouver
Joined Oct 2007
322 Posts
Thanks Umi,
If I am not working I will be there for sure.
Thats the trouble with driving yachts for people, they want to use them all the time in the summer. Last year I was away every long weekend which got me sh from the wife but how else am I going to pay for the models, I mean mortgage
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Old Jan 05, 2008, 12:52 PM
Registered User
Joined Apr 2007
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This looks pretty neat! Very clean job framing it up.

I have a question about the skeg / fin with regards to the VS drives in scale models

I understand the purpose of the fin during escort work. However, how much fin is really necessary for a scale boat using the Graupner VS drives. I have read a bit about the VS drives and have seen Keith's 'Wedell' in action (with a modified skeg and z-drive). What I am trying to ask is....because the Graupners are not as powerful as full size VS drives, is it necessary to reduce the fin size to compensate and improve manuverability?
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Old Jan 05, 2008, 01:11 PM
USA'd ex Brit
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Back.. In California
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Quote:
Originally Posted by Tugboat Andy
I have a question about the skeg / fin with regards to the VS drives in scale models

I understand the purpose of the fin during escort work. However, how much fin is really necessary for a scale boat using the Graupner VS drives. I have read a bit about the VS drives and have seen Keith's 'Wedell' in action (with a modified skeg and z-drive). What I am trying to ask is....because the Graupners are not as powerful as full size VS drives, is it necessary to reduce the fin size to compensate and improve manuverability?
I think reducing the skeg on a scale model with Voith drives would probably make the model LESS manouverable Andy. My understanding for the purpose of the skeg is that it acts as a 'lever' (against the water) for Voith drives.. and hull to turn against...
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Old Jan 05, 2008, 01:40 PM
Yacht Captain
yacht boy's Avatar
Canada, BC, North Vancouver
Joined Oct 2007
322 Posts
Andy,
I get your point, but I do plan to use the model in the same way the full size tugs work.
Myself and another member of the club plan to build a water ballasted 9' ship model, probably weighing in at about 350 - 400lb when ballasted.
The idea is to manouver the ship into a berth with two or more tugs. Much more fun than running free.
I have a water ballasted barge that weighs 220lb when ballasted which I tow with my Tito and there is allways another tug around to help dock it.
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Old Jan 05, 2008, 01:59 PM
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I think we are on the same page. I was just reading it upside down

Please keep us updated with lots of pictures and how-to's. Inquiring minds want to know....
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Old Jan 05, 2008, 05:43 PM
USA'd ex Brit
toesup's Avatar
Back.. In California
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Quote:
Originally Posted by yacht boy
Myself and another member of the club plan to build a water ballasted 9' ship model, probably weighing in at about 350 - 400lb when ballasted.
The idea is to manouver the ship into a berth with two or more tugs. Much more fun than running free.
I have a water ballasted barge that weighs 220lb when ballasted which I tow with my Tito and there is allways another tug around to help dock it.
Having chatted with the owner of a twin (Graupner) Voith propelled tug, he gave me the impression that the Voith units gave the tug excellent manouverability over a screw propelled tug and probably over a Z drive tug...
However, he did mention that the Voith units were not very powerfull when it came time for some pull / push...

Perhaps Umi could throw some light on this?... Would upgrading the motor make a difference or would it overstress the voith units?

I have yet to try out the Voith units i have.
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Old Jan 05, 2008, 05:52 PM
Sea Dragon-Lover
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PDX, OR
Joined Dec 2002
9,836 Posts
My motors tend to run a bit hot. I am even considering cooling them..
I have some other motors, but I think that a lower RPM they provide will
make the performance suffer.

Stock, I need full throttle to get the boat to crab sideways well.
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Old Jan 05, 2008, 06:10 PM
no wings any more, just dust!
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stoke on trent
Joined Oct 2004
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can someone explain how the voith drives actually work, im guessing that they have adjustable paddle angles like a rotor hub
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Old Jan 05, 2008, 06:13 PM
USA'd ex Brit
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Back.. In California
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Quote:
Originally Posted by Ghost 2501
can someone explain how the voith drives actually work, im guessing that they have adjustable paddle angles like a rotor hub
Yes i could...

But this explains it better...
http://users.skynet.be/havenslepers/en/doc/vsp.htm
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Old Jan 05, 2008, 06:18 PM
Intermediate Multi
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Columbus, OH
Joined Mar 2005
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I like the modern looking cabin. I hope the pilot has enough visibility in there.

Tom
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Old Jan 05, 2008, 06:29 PM
Registered User
Joined Apr 2007
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Quote:
Originally Posted by toesup
Yes i could...

But this explains it better...
http://users.skynet.be/havenslepers/en/doc/vsp.htm
Huh....that's pretty cool. I wonder what the life span of the parts are. I would assume that there would be some wear on the main control parts.
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