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Author Topic: Indirtect Tow  (Read 2387 times)

farrow

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Indirtect Tow
« on: August 25, 2008, 09:46:11 pm »

Found these photos of a tractor tug doing an indirect tow there is about ten in all showing the sequence, but that would be to much to upload. For the uninitiated the tug reverses and side thrusts to the tow, this gives a stronger directional pull than going ahead and trying to thrust at an angle to achieve the directional pull, but only effective if the tow has way on.
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Gavin

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Re: Indirtect Tow
« Reply #1 on: October 23, 2008, 07:10:06 pm »

WOW thats what i call towing just shows what the latest tugs can do!!!!!
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packy46

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Re: Indirtect Tow
« Reply #2 on: October 26, 2008, 03:36:27 am »

Thats work....
Great pictures.
Tim
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Umi_Ryuzuki

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Re: Indirtect Tow
« Reply #3 on: October 26, 2008, 06:07:16 pm »

So If I understand this process, the tug is steering or braking by
using the hull as a rudder force?
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toesupwa

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Re: Indirtect Tow
« Reply #4 on: October 27, 2008, 01:47:06 pm »

So If I understand this process, the tug is steering or braking by
using the hull as a rudder force?

The hull of the tug is used as a 'drag brake' by the ship that it is attached to.

By careful steering by the tug captain, its possible to get 2 - 2.5 times the braking effect (bollard pull) that the tug would get by just using its engines alone.
http://www.towingsolutionsinc.com/technology-escort_restricted.html
Read 'Indirect towing'..
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poll

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Re: Indirtect Tow
« Reply #5 on: October 27, 2008, 10:12:48 pm »

This is the carrousel tug 25 tonne bollard pull,  working in the girted postion becomes 115 tonnes.

John.
            PS also a working model
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ian kennedy

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Re: Indirtect Tow
« Reply #6 on: October 28, 2008, 09:47:58 pm »

Looks like your boats sinking mister !!!!

Seriously this is an excellent boat to watch at the stern of the tow acting as a drag anchor and getting pulled under the surface.

I have seen this a number of times this year and if you get the chance to get to a Balne moor towing event next season you will have an excellent day, mixing with very mad friendly tug nuts

Ian
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farrow

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Re: Indirtect Tow
« Reply #7 on: October 29, 2008, 08:02:14 pm »

I think you have slightly got the wrong end of the theory. The idea is to drive your tug at an angle to the direction of the movement of the tow to turn the tow like a detached rudder, using the tugs keel as a auxiliary rudder to the tow. To put the tug at 90 degrees to the tow movement and use her as a big sea anchor drag would most likely cause  a real tug to possibly sink or damage her tow gear badly.
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poll

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Re: Indirtect Tow
« Reply #8 on: October 29, 2008, 10:16:23 pm »

I think you have slightly got the wrong end of the theory. The idea is to drive your tug at an angle to the direction of the movement of the tow to turn the tow like a detached rudder, using the tugs keel as a auxiliary rudder to the tow. To put the tug at 90 degrees to the tow movement and use her as a big sea anchor drag would most likely cause  a real tug to possibly sink or damage her tow gear badly.
Hi rmasmaster,I don't think I've got the wrong theory, this is how the carrousel tug operates, It works just the same if It's on the bow or the stern. The tug is designed to tow on the ring which runs 360 degrease round the tug, so when the tug is girted it pulls from out side of the hull so less or no chance of it turning over.
Regards

John
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farrow

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Re: Indirtect Tow
« Reply #9 on: October 30, 2008, 05:54:10 pm »

Well thats a new one on me, when I worked in the RMAS, we did indirect tows when stern tug to assist in turning the the towed vessel when it was moving forward. We all thought at the time that this is a good practice, but we found out afterwards that it had been calculated that in theory you can roll a tractor tug when carrying this practice.
As I said at the start it is a new one on me these carousel tugs, I cannot comment on them as I have no experience of them, but all the same I would still be cautious about girting one when the tow was moving through the water.
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poll

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Re: Indirtect Tow
« Reply #10 on: October 30, 2008, 08:03:33 pm »

Hi Rmasmaster, If you Google Novatug.com  you will see the working of the carrousel tug.

John.
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Andy K

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Re: Indirtect Tow
« Reply #11 on: October 30, 2008, 08:26:18 pm »

The european company that is manufacturing these type of tugs is Mampaey, have a look at their website they have links to videos on youtube.

Andy
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Andy K

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Re: Indirtect Tow
« Reply #12 on: October 30, 2008, 08:26:51 pm »

www.mampaey.com look under dynamic oval towing.

Andy
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farrow

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Re: Indirtect Tow
« Reply #13 on: November 06, 2008, 10:49:57 am »

Many thanks Artic Helios, the film clip was very informative, it does confirm my original suppostion, it is still highly dangerous to girt a tug. From I can see the system is to allow more freedom of movement for tugs with limited arcs of thrust such as screw tugs etc to manoeuvre when connected by a towing hawser.
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