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Old Apr 07, 2008, 09:07 PM
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Rotor Tug, Regular Ole' Tug, Harbor Tug. What Is A Tractor Tug?

I've heard of several different types of Tugboats but I'm not quite sure I understand exactly what a "Tractor" tug is. Hmmm... Can anyone describe to me what a Tractor tug is and what makes it different from other types? Any pictures of one of these animals??
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Old Apr 07, 2008, 09:54 PM
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It was my impression that a tractor tug has the drives forward of the centerline...
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Old Apr 07, 2008, 11:38 PM
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As I understand it....

VSP = Voith Schneider Propeller
ASD = Azimuthing Stern Drive
Z-drive = Schottle Drive = ASD

The rotor tug uses three z-drives. Two forward, one aft.

The tractor is as Umi describes. But I understand this can be VSP or Z-drive.

Enhanced tractor (FOSS version) has two VSP's forward with a z-drive aft.

An ASD tug has two z-drives aft, facing aft.

Am I missing something.
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Old Apr 08, 2008, 12:30 AM
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I think it is less precise than described above. While not implying that that is wrong, I belive it is more loosly used to describe coastal and harbour "vessel assist" tugs.
In the same way you would describe an "Ocean tug" or Coastal tug" both implying line tows. Then a tractor tug would supply manouvering and docking traction for vessels lacking that ability, either by pulling or pushing without the need to turn the tug around.
It has ocured to me while writing that the tugs I am trying to describe all have a common unique feature, they are able to run in both directions
Ahead for pulling, and astern for steerage (when the tow line is secured to the transom of the assisted vessel) with 2 sets of nav lights to suit.
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Old Apr 08, 2008, 08:07 AM
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Umi and Tugboat Andy have it nailed.

The term "Tractor" correctly refers to a tug with units forward, be they V/S or z-drive. In recent years, I've heard some maritime folks refer to any tug with V/S or z-drives, forward or aft, as a tractor. This just shows laziness or ignorance on their part.

Although there might be one out there, I've never seen or heard of a ship-assist tug with aft mounted V/S units. It would totally kill any advantage that those units possess.

Industry people generally refer to any tug with an ASD aft as a "Z-drive" tug. Yes, they've taken a brand name and applied it generically, like aspirin.

Years ago, before "z-drive" became the norm, any tug with units aft was referred to as a "reverse tractor tug."
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Old Apr 08, 2008, 02:56 PM
master boat slacker
USA, NY, Mastic Beach
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i had my tractor tuged today



stuck in the mud!!
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Old Apr 08, 2008, 03:41 PM
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So then is Umi and Tugboat Andy correct on this one or is everyone correct? All very good info here. I didn't really understand the term "tractor" when it came to tugs but now it makes sense.

So what would the Mr. Darby tug be considered? A Harbor Tug? Salvage Tug? I'm considering buying a Harbor Models version Mr.Darby with the large Pittman motors and Kort nozzel drive system, I've wanted it literaly for years and I think I can finally fund the project. Ohh I can't wait.
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Old Apr 08, 2008, 04:09 PM
r/c ships and workboats
bellingham, wa
Joined May 2006
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Quote:
Originally Posted by boat_builder
So then is Umi and Tugboat Andy correct on this one or is everyone correct? All very good info here. I didn't really understand the term "tractor" when it came to tugs but now it makes sense.

So what would the Mr. Darby tug be considered? A Harbor Tug? Salvage Tug? I'm considering buying a Harbor Models version Mr.Darby with the large Pittman motors and Kort nozzel drive system, I've wanted it literaly for years and I think I can finally fund the project. Ohh I can't wait.
Oacean going tug. Can also be used to convert into an ATB ( articulated tug and barge), salvage tug, coastal tug, big a## tug, or anything else that looks similar. good luck and keep us informed if you build one!
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Old Apr 08, 2008, 04:43 PM
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simple way, two types, PUSHER and TRACTOR, the pusher tug does what it says in its name, pushes the barge from behind, flat bow, with upright posts that push against the transom of the barge, these often ply inland waterways

Tractor Tug: this type of tug pulls the barge, usually by means of a tether, quite often, this type of tug is used in ports to berth things like ocean liners and tankers, working in teams.

Thats my theory on the terminology.
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Old Apr 08, 2008, 06:59 PM
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capntroy,
Without Malice, (lawyer speak for, not trying to p s you off but)
Not sure I like the inference of lazy or ignorant
So I thought I would back up my point.
First off I went to Wikipedia, no definition for "Tractor Tug"
So then I simply googled the term.
Some of the results where indeed "drive forward"

http://www.crowley.com/vessel-constr...actor-tugs.asp
But it will be noted that the text refers to tractor tugs "designed for ship assist and escort"
This is a recuring coment in all references to tractor tugs.

There where also drive aft results.

http://www.nicholsboatscom/baydelta.htm


http://www.morantug.com/news1102b.asp
And a picture of the Kaye E. Moran underneath.

http://www.seaspan.com/docs/Harbour%...-%20July07.pdf

and i think this little comentry covers it nicely

http://archive.seacoastonline.com/20..._wate/69356htm
So once again I would suggest the generally accepted meaning for the term "Tractor Tug" is a tug that would supply manouvering and/or docking traction for vessels lacking that ability.
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Old Apr 08, 2008, 07:13 PM
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The first "tugboats" (at least as we know them) were side wheel paddle boats or screw propellor boats. Most towing was done "on the hawser" over the stern. Im some case, barges or ships were towed "on the hip" or moored alongside the tug. Tugboats were often designed and built for a specific purpose, such as ship handling, towing railroad carfloats, or salvage and rescue.

At least in the USA, "towboats" were developed from the old side and stern wheel river boats - to push the tow ahead of the towing vessel. These tow boats are commonly (and wrongly) referred to as pushtugs.

Since WWII, there have been many different developments in marine propulsion, which brings us to the term "tractor tugs". These usually have a VS or Azi-pod (Z-drive) units mounted forward of amidships, rather than at the stern as in traditional tugs.

The original MR DARBY was built as an anchor handling tug; to handle anchors for the offshore oil wells. It also took supplies out to the oil rigs.

There are several good reference books on tugs and towing. Here is a partial list:
Tugboats of the Great Lakes by Franz Von Riedel
Tugboats by Jim Shaw
On Tugboats by Virginia Thorndyke
Tugboats and Towlins by Warren Salinger
Primer of Towing, 3rd edition
On the Hawser, A Tugboat Album
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Old Apr 08, 2008, 08:22 PM
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Quote:
Originally Posted by yacht boy
Some of the results where indeed "drive forward"

But it will be noted that the text refers to tractor tugs "designed for ship assist and escort"
This is a recuring coment in all references to tractor tugs.
I saw the press release for the new Seaspan Z-tech and didn't think twice about it...until now! With the drives in that configuration I would have assumed it would have been labeled a ASD escort tug, not a tractor tug! So I poked around my usual haunts and found this thing:

http://www.voithturbo.com/applicatio...1826_himet.pdf

Indeed, it seems the 'rules' are a little blurry. At least B & B and Crowley have the grace to label their boats fin first tractors...

http://www.bube.no/escorttugtech.asp
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Last edited by Tugboat Andy; Apr 08, 2008 at 09:06 PM.
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Old Apr 08, 2008, 08:36 PM
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we have tractors tugs here in saint john nb can.the company that owns them,uses them moving log and pulp booms around their mills,soory thier mill ponds and river
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Old Apr 08, 2008, 09:16 PM
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At the lower right there is a video of a fin first tractor tug working out on an ship riding high.

http://www.bube.no/ser_shipescort.asp
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Old Apr 08, 2008, 09:52 PM
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Quote:
Originally Posted by Tugboat Andy
At the lower right there is a video of a fin first tractor tug working out on an ship riding high.

http://www.bube.no/ser_shipescort.asp
Nice little diagram on their website also..
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