Articulated tug and remote helm for floating hotel

Discussion in 'Boat Design' started by yodani, Aug 4, 2014.

  1. yodani
    Joined: Nov 2010
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    yodani Senior Member

    Hi there,

    I am thinking of possibilities to improve on "perfection" due to new EU regulations coming our way so I came up with this idea. Let me explain...

    In the 50's on the Danube was introduced this towing system for various barges, floating hotels etc. It has worked flawlessly ever since but now the EU regulations are threatening my business. We operate since 25 years now these floating hotels tugged by tug boats via two ropes as seen in the pictures attached. On board the hotel there can be up to 20 guests plus 4 crew members and on the tug two crew members.

    The floating hotel is flat bottom with a max draft of about 60cm, a beam of 5m, 32m long with a 4m wind surface above the water.

    The tugboat is about 16m long with 3.5m beam and a draft of 1.2m capable of towing the convoy with about 10km/h (depending on current and wind) using its old Russian tank engine - 150hp@1800 RPM and consuming between 20 and 24 liters/hour.

    Now the problem:

    The new regulations try to forbid us to tow the floating hotels if there are people on board plus they try to force us to use "highly" trained captains for the job (a bureaucratic thing) to make more money from taxing etc. This regulation is applying only if the boat is towed but not if it is pushed...

    I think you start to see my problem now. There are a few solutions to this:

    1. You can modify the floating hotels but this is more than complicated and will push the boat into "passenger vessel" regulations... meaning more crew, more money more fuel burned etc. so this is out of the question.

    2. Change the towing with pushing but this comes with its own problems... you can push alongside on the main channel but not in the narrow channels and the maneuverability is poor with bad visibility for the captain. We do this only when need to moor the boat in a tight place.

    3. Make a new towing method that would add maneuverability, safety and keep the boat going alongside the sinuous narrow channels. Positioning the tug in the back of the convoy will increase maneuverability, but will add a couple of issues:

    - absolutely no visibility due to the height of the floating hotel (4m).
    - increase the length of the vessel to 48m or more and that is going to make impossible for the convoy to manage the meanders and also turn on narrower channels.

    This brought me to the following idea but have no clue if it would be viable or not - an articulated hydraulic steering between the tug and the convoy. The advantage for this particular application would be:

    - increased maneuverability by adding thrust vector just like an outboard using the articulation and the rudder effect
    - possibility to make tight turns on channels
    - safer as the convoy can be stopped by reversing - something not possible with the rope towing

    Challenge:

    Make a remote helm on board the floating hotel to control the tug - would this work? would it be legal?

    Find a way to control the hydraulic articulation and the rudders in the same time.

    Qestions:

    1) Do you know of a way to remotely control an engine and steering safely? It can be by wire or hydraulic but also radio controlled (Here there are safety issues). It must be a way to quick connect and disconnect as the tug will be removed often.

    2) What kind of redundancy can be build into this?

    3) Would this kind of connection last and be safe?

    Enough for now... I hope I was clear enough about what I want and I hope you can come up with some advice and ideas.

    The principle is exactly like an articulated loader:
    [​IMG]

    [​IMG]

    Cheers,

    Daniel
     

    Attached Files:

  2. yodani
    Joined: Nov 2010
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    yodani Senior Member

    Also...

    As the floating hotel has so much wind surface how would be the handling in ruff winds when pushing? At the moment when towing in cross wind we have problems sometimes as the hotel is dragging sideways and sometimes touching the shore, trees etc.

    I was thinking about a bow thruster to be integrated with the steering but on a flat bottom the only solution would be to build this kind of keel on the bow- http://www.billmunsonboats.com/monohul.php# ?

    The other thing is the tug boat length and motorization. Ideally would be to build new mini barge pusher just like in the quick 3d renderings I made.

    This is a bit far fetched but doable if can access some EU funding in the future. The most important cost in operation of our boats is the fuel as now we pay 1.45 EURO/liter that makes our tours more and more expensive and hard to sell. With a new push tug we could improve on that plus give some redundancy to the boat by using twin engines.

    The problem is also that we need to keep the power at max 185Kw or 250hp to stay in the boat category accepted by the regulation. Would two 100hp engines be more economical than one 250 hp engine? Will we be able to make fuel economy with the newer engines? I mean it is hard to beat 20 liters/hour but maybe by the gained speed we could improve?

    Too many questions ... to many ideas... sorry for the long monologue.

    Daniel
     
  3. rwatson
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    rwatson Senior Member

    Complicated - why dont you just use a second tug all the time like one of those pictures ?

    Extra thoughts -

    The real problem is probably the lack of co-ordination of the 3 units - lead Tug, Barge, and tail tug.

    When they link three locomotives together on big haulage jobs ( sometimes a prime mover at the rear ) they have 1 computer to control all the units.

    You dont have train tracks to solve some of the problems, but i bet they dont have a centrally controlled system so that one operator can adjust all vectors.
     
    Last edited: Aug 4, 2014
  4. yodani
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    yodani Senior Member

    Hi Rwatson,

    How is that more complicated than using two tugs?

    I am also looking for maximum efficiency and by adding a tug you have to have and extra boat... crew ... etc ... etc.... money money money... :)
     
  5. TANSL
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    TANSL Senior Member

    My humble opinion: for these maneuvers the tug must have absolute freedom of movement, including the ability to break away from the pontoon. Therefore, all that is limiting the movements of the tug can reach even be dangerous.
    A bow thruster is a very good idea, imo.
     
  6. rwatson
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    rwatson Senior Member

    NOW you tell us !! :)

    Wait till you start designing the 'new' invention, and the 2nd tug will look cheap.

    TANSL has made a really important point - forces on a semi-rigid articulated joint have the potential to be huge - ripping chinks out of one or more of the boats.
     
  7. yodani
    Joined: Nov 2010
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    yodani Senior Member

    Hi Tansl,

    Even now when we side push we need to secure the tug with about 4 ropes in order to safely maneuver it is true that the boat has the ability to freely move in case of chop but detaching shouldn't be more complicated than this if we use winches just like a normal push barge.

    In the end is rwatsson's observation about the strength of the hinge and the the hydraulic cylinders that has to be addressed and the remote helm witch can be done by wire and be disconnected by unplugging a simple plug.

    A barge - tug connection purpose is to make them as one so there is not much movement.

    I have seen the - Articulated Tug Barge - at 2:25 you see how it works. The thing is that is articulated on the "wrong" axis :)..
    https://www.youtube.com/watch?v=DlFNwcjLyx0

     
  8. TANSL
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    TANSL Senior Member

    What you see in the video is not a new invention. For many years this semi-articulated thrust system is used. After many years of experience they have not changed anything in the system so we can not say that it has a major defect.
    For other types of vessels and form of pushing, I think you should not extrapolate. To maneuver in tight places, I think it is not suitable.
    The tugs have, in many cases, an artifact of "quick release" to avoid embarrassment. You may provide a mechanism of this type.
    I have not thoroughly studied your system and therefore I can not say it's good or bad. Just tell you that you should avoid to prevent the tug can do a specific maneuver, in a hurry cases.

    "A barge - tug connection purpose is to make them as one so there is not much movement. " : A rigid connection between two bodies can be a serious problem. Always prefer an articulated joint.
     
  9. yodani
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    yodani Senior Member

    Thanks for the reply. I know is not new but it is everything I could find about it.

    I was thinking about an automatic attachement and have a few ideas. I have seen this article - http://www.maritimejournal.com/news.../british_waterways_invest_in_new_mini_pushers

    "Efficiency in operation is improved by fitting a hydraulic latching device enabling rapid connection to barges. Conventional push/tow winches are also fitted for use with craft not fitted with a dedicated pushing knee. "

    Do you have any idea what a hydraulic latching device looks like?

    Cheers,

    Daniel
     
  10. yodani
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    yodani Senior Member

  11. gonzo
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    gonzo Senior Member

    I think that if you remotely steer from the forward barge, it may legally become the tug. Also, having a bow thruster may or may not make it a power driven vessel (Admiralty lawyers may have to be consulted on that). However, rather than steer remotely, can you install camera systems to give you forward and lateral views? It is not different to maneuvering while using a radar in the dark or fog.
     
  12. yodani
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    yodani Senior Member

    Hi Gonzo,

    Thanks for your thoughts. I know you are in this business a long time so you know a lot about boat design. This remote steering is a tricky one but it can be done with existing tech.

    The camera system came to my mind but I am afraid it would prove to be a bit difficult as you will have to anticipate trees and logs in the water plus incoming traffic on a wild channel 3m wider than your convoy. On open water it is much much easier as you can anticipate things.

    The legal stuff that's the scary part :)
     

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  13. Rurudyne
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    Rurudyne Senior Member

    Your hydraulics need to be set wider apart at the bow than you've shown in the picture to help facilitate control.

    Another option would be to establish an intermediate, um, plane of action between the bow of your tug and the transom of the barge: a rigid beam on which hydraulics from fore and aft could operate in place of the henge. This would spread the forces out and help prevent the barge and tug from bending too much and loosing control.

    Bendy buses use a similar set up ... though I don't know if that's a recommendation to you're mind. ;)
     
  14. gonzo
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    gonzo Senior Member

    This is one of those situations where laws are written by people without knowledge. They may have good intentions but don't understand what is that they are regulating. I would like to read the logic of the difference between a tug pulling or pushing.
     

  15. TANSL
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    TANSL Senior Member

    It should be something like having a car with rear wheel drive or front wheel drive.
    A tugboat "pulling" always has better forward vision that "pushing". Maybe this affects how the tug should work in every case.
     
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