Hydrostatics and Intact Stability of tug 25m

Discussion in 'Stability' started by Rabah, Aug 19, 2015.

  1. TANSL
    Joined: Sep 2011
    Posts: 6,114
    Likes: 268, Points: 93, Legacy Rep: 300
    Location: Spain

    TANSL Senior Member

    I have just a couple of arguments, I do not know whether they are important or not. You judge them.
    First: propellers often wear those ships can not be installed at the stern that you have designed. Stern needs a completely flat areas that your boat does not have.
    Another argument: When a tug is pulling a boat, it needs a lot of reserve buoyancy aft. Remove aft volume is therefore a serious mistake.
    I hope you listen to me, preferable than others have to ask you to modify your project or, what is worse, they seek another designer is to design them a proper boat.
    As always, I am happy to help. Cheers.
     
  2. Ad Hoc
    Joined: Oct 2008
    Posts: 6,490
    Likes: 550, Points: 113, Legacy Rep: 2488
    Location: Japan

    Ad Hoc Naval Architect

  3. TANSL
    Joined: Sep 2011
    Posts: 6,114
    Likes: 268, Points: 93, Legacy Rep: 300
    Location: Spain

    TANSL Senior Member

    Ad Hoc, thanks a lot for your always expert comments. I know very well Robert Allan tugs as I have been involved in the construction of 5 of them. They have nothing to do with the type of tugboat that we are talking about. For what we talk about Robert Allan tugs do not serve well, so thank you for a comment that is beside the point. The ports around the world are full of tugs that are not Robert Allan design and OMG perfectly meet the mission for which they were designed.
     
  4. Ad Hoc
    Joined: Oct 2008
    Posts: 6,490
    Likes: 550, Points: 113, Legacy Rep: 2488
    Location: Japan

    Ad Hoc Naval Architect

    Tansl

    AS always you seem to be able to add 2 + 2 and make = wednesday!!!

    You consistently appear incapable of following a simple line of logic, yet criticise others for some bizarre reason because you don't follow the logic!

    What is posted by the OP...hmmmm??..is there a profile GA...oh yes!!!...and oh..is there a profile GA in the RA link...oh yes....and if placed side by side these 2 GAs...is there a striking similarity or do they look as far apart as your ability to follow logic!
     
  5. TANSL
    Joined: Sep 2011
    Posts: 6,114
    Likes: 268, Points: 93, Legacy Rep: 300
    Location: Spain

    TANSL Senior Member

    Ad Hoc,
    I think, and if I'm wrong I'm sure you know forgive me, that the logic of this forum is that someone poses a question and others, on that basis, make our comments, free but polite way, without arrogance.
    The OP poses a boat and I think, from my experience, that is wrong, it has serious flaws. I put it this way and explained my reasons. It is that wrong done ?.
    You make a comment, following I don't know which logic (where is your ability to follow logic?), that does not come to mind and I said so. Is that wrong done?
     
  6. Rabah
    Joined: Mar 2014
    Posts: 247
    Likes: 7, Points: 18, Legacy Rep: 50
    Location: Bulgaria

    Rabah Senior Member

    Hi Tansl,
    In your arguments absolutely there is not a logic.
    Who say you that ASD it is necessary to install only on a flat site?
    In the original they are installed pitched towards BL, they are in two planes, parallel towards CL and in the original hull too there is rise of bottom up to neighboring area of a transom.
    The note from reserve buoyancy too denuded from sense as the original ship fulfills the functions.
    ____________________________
    NA Razmik Baharyan
     
  7. Rabah
    Joined: Mar 2014
    Posts: 247
    Likes: 7, Points: 18, Legacy Rep: 50
    Location: Bulgaria

    Rabah Senior Member

    Hi Ad Hoc,
    You make very malicious hint, whether you think?
    But I in the beginning have written what is the variance from original. In all remaining I tried to be possible close to original buttock-lines, frames and water-lines.
    I have only offered more technological version!
    Certainly that the tug of Damen is very good, but also they are not gods, for them too is the competitors. They very long time specialize in this area.
    Except for that thus you belittle yourself. Really you are poorer shipbuilder than they?
    ________________________________
    NA Razmik Baharyan
     
  8. Rabah
    Joined: Mar 2014
    Posts: 247
    Likes: 7, Points: 18, Legacy Rep: 50
    Location: Bulgaria

    Rabah Senior Member

    Hi All,
    Let's see how is calculated on Delftship Professional Towing and Turning Stability.
    Necessary initial data and outcomes:
    A. Towing Stability
    For escort tug heeling arm:
    Towing force = 45t
    X coordinate = 7.83m from AP
    Y coordinate =0
    Z coordinate = 5.37m from BL
    Lateral center of effort - from Silhouette
    Angle of admissible heel = Deck immersion angle = 20deg
    As we know draft by full displacement, but we do not know Deadweight, in Wight table it is supplemented equal values for Lightship and Displacement but Deadweight conditionally it is received = 0.
    In the total is received heel angle 17.5deg <20deg by Heeling Moment = 182.34 t.m

    B. Turning Stability
    Service speed = 15 knots
    Radius of Turn = 1.5 L
    Required value of heel angle = 10deg / it is received as for passenger ship/
    We receive heel angle 6.5deg <10deg by Heeling Moment = 67.285 t.m
    The freeboard is received quite sufficient.

    At least I have executed even one of my purposes - to acquaint you with excellent capabilities of program Delftship Professional.
    It in any way do not belittle my respect and preference to program Maxsurf Stability.
    It is time to finish this publication differently the head of Mr. Tansl will be hurt again from all these calculations.
    ______________________________
    NA Razmik Baharyan
     

    Attached Files:


  9. Rabah
    Joined: Mar 2014
    Posts: 247
    Likes: 7, Points: 18, Legacy Rep: 50
    Location: Bulgaria

    Rabah Senior Member

    Hi All,
    At last has decided to show you Damen ASD Tug 2810 which has the close sizes, rise of bottom in a stern in the zone of installation ASD and also as well as the original tug adopted from me has the round bilges. The form of keel almost equal in Profile.
    ______________________________
    NA Razmik Baharyan
     

    Attached Files:

Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.