Launching and recovering large heavy boats without a crane

Discussion in 'Boat Design' started by Annode, Sep 4, 2019.

  1. Annode
    Joined: Aug 2019
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    Annode Junior Member

    When considering a restoration project for older large steel boats 200+ tons, it becomes rapidly apparent that getting them in and out of the water for a hull inspection is beyond the capabilities of most boat yards. The only solution appears to be a slipway. There are very few cranes in the countru that can handle that weight at the distance of the center line of the boat from the dock.

    Thinking out of the box is required. watching launch videos of large ships, they allow them to slide into the water sideways:

    if possible, this launch technique would solve half the problem (getting the boat out)
    This might be the wrong forum for this, but I am curious why sideways these days?
    How did they get the boat onto the steel launch ramps?
    Was it built there?
    Are the sleds on rollers or just heavily greased metal to metal?
     
  2. DCockey
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    DCockey Senior Member

    Side launching is used to launch newly constructed vessels, not for relaunching hauled vessels. The vessel is either built in place or moved into position after being built elsewhere in the yard.
     
  3. Annode
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    Annode Junior Member

    What about these inflatable rollers?

    Seems these could be used to slip and drag a boat to a hard stand?



    [​IMG]
     
    Last edited: Sep 4, 2019
  4. Squidly-Diddly
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    Squidly-Diddly Senior Member

    first built a floating, semi-mobile dry-dock. This could be done modular starting with a foundation of blocks of standard shipping container size. Have the blocks, with some plumbing to flood/drain ballast tanks, built in China or India for cheap, load them on a ship able to crane the blocks over the side by itself, then assemble at your location.
     
  5. Ad Hoc
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    Ad Hoc Naval Architect

    I don't understand what this means.
    It is the usual go-to phrase used by many that do not work in the field/industry and have no idea of what work is done behind the scenes. It is typical gobbledegook management speak.

    Sideways launching is very common in locations that do not have the luxury of space. Launching length ways a 100m vessel on a river that is only 50m wide is clearly impossible. Yet with a beam of 20m launching side ways is very easy.
    This method overcomes difficulties with the space and depth of water required for a conventional lengthwise launch.

    No. As DC Notes, how do you move the vessel from floating to the hard....you need major heavy lift equipment to over come gravity at such an acute angle of displacement.

    Same as above. You need major heavy duty equipment to overcome gravity - like winches etc.

    I fail to understand what your question is...other than, big heavy boats need big heavy equipment to slip...
     
  6. Annode
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    Annode Junior Member

    Thinking out of the box...
    >I don't understand what this means.
    >big heavy boats need big heavy equipment to slip..
    >you need major heavy lift equipment

    <sigh> NOT using a crane... using inflatable rollers for example... see videos of very heavy ships rolled into the water..
    Ship Launching Airbags - Blue Ocean Tackle http://blueoceantackle.com/marine-supply-equipment/launching-airbags/

    If a 320 ton boat can be pulled up a mountain and down the other side for a darned movie, im fairly sure a 100 ton steel hull can be dragged around without a crane!
     
  7. KeithO
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    KeithO Senior Member

    Movie producers sometimes spend a LOT of money on special stunts that they think are key to the storyline. That doesnt mean its economical to apply that method to an old vessel you want to restore. The air bags only work on structurally sound flat bottom boats.

    If it is not a flat bottom boat, you need to have the vessel lifted onto a barge and set in a cradle on top of it, then roll the barge out on the airbags. Or, as was done for the Idlewild expedition, make up multi axle trailer bogies, and weld them to the hull after getting them aligned with divers. Attachment points/bracing can be above the waterline.

    Again, few of these options are inexpensive and there is plenty that can go wrong, especially on an older vessel that may not be perfectly sound structurally... I was a combat engineer and we drug granite boulders around with manilla rope, greased timber and hand winches, but thats not necessarily because it was a good idea, it was done because it was hard and dangerous and the officers were getting us to do things we were convinced were impossible...


     
  8. RAraujo
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    RAraujo Senior Member - Naval Architect

    Have a look at this (this is from Portuguese Navy shipyard - Arsenal do Alfeite). It is a mechanical sideways launching and hauling equipment dating back to WWII but still in use.

    [​IMG][​IMG][​IMG]
     
    Last edited: Sep 5, 2019
  9. DCockey
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    DCockey Senior Member

    Looks like it is a transverse marine railway.
     
  10. waikikin
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    waikikin Senior Member

    Here's a nice little vid of pulling a boat out. Pretty cool museum boat now.

     
  11. Rumars
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    Rumars Senior Member

    What's technicly possible and what makes finnancial sense are two kettle of fish. The normal option is to prioritize the finnancial side. If the sensible thing is to tow the boat to Holland to a drydock then that's what you do.
    "Alternative arrangements" are only required under special circumstances. For example you own a ramp (and the associated yard) big enough for the boat but without all the lifting gear so you start thinking about air rollers. The actual lifting will be more expensive but the overall cost of the renovation could be less. Or maybe not, it's a case by case thing.
     
  12. Annode
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    Annode Junior Member

    Has anyone created a temporary lock to lift a boat onto dry land?
     
  13. RAraujo
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    RAraujo Senior Member - Naval Architect

    Have a look at this (Lisnave shipyard in Setubal, Portugal):
    [​IMG]
     
  14. Ad Hoc
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    Ad Hoc Naval Architect

    A graving dock basically!
     

  15. RAraujo
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    RAraujo Senior Member - Naval Architect

    Yes, but the dock bottom is above the water level...
     
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