Hull turning - engine & gantry crane

Discussion in 'Boatbuilding' started by Wckoek, Apr 3, 2018.

  1. Wckoek
    Joined: May 2016
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    Wckoek Junior Member

    I have a 2 ton engine crane and have access to a 2.5 ton gantry crane, have anyone use such crane to turn a hull?
    On a seperate question, if both 2 and 2.5 ton crane used together, can they lift a 4 tonne boat?
     
  2. PAR
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    PAR Yacht Designer/Builder

    Are these chain fall hoists? Is the engine crane, an engine boom hoist, with a projecting or even telescoping boom? Most engine hoists will do 2 tons, but only in the fully retracted position, which may not offer enough height or reach. You'll need both to roll her over.
     
  3. gonzo
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    gonzo Senior Member

    We have turn many hulls with straps wrapped around them. You pull from one end, and the hull rolls on the straps.
     
  4. Wckoek
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    Wckoek Junior Member

    Yes, the gantry is chain fall hoist, the engine crane is of telescopic boom that lifts up to 2.36m according to the manual with a range of 1-1.6m.
    I am thinking of lifting the bow side with the engine hoist, and use strap on the gantry to flip her over, but I never seen such a setup being used before, and what should I look out for.
     
  5. PAR
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    PAR Yacht Designer/Builder

    I've done just what you described and just go slow, insure you can "catch her" if things get out of hand and eventually you'll find you thought and worried a lot more about this than necessary.
     
  6. Jack1.0
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    Jack1.0 New Member

    Hi...

    New poster here!

    I've been lurking for years, but as I'll be looking for some design advice shortly. I thought a bit of participation was called for first ;-)

    This seems to be a current post so:
    There are a lot of methods to turn a hull, and most work okay. There is no right way in my mind!
    I've built a lot of boats - normally to the hull and deck stage for owner completion. Steel, Alloy and Glass-Ply.
    Here's just another method of turning a hull. I can't remember where I first saw it done, but I've done it 11 times on steel hulls up to 43' and 3 times on aluminum to 39' with no issues. It took me 6 hours to turn this hull including finding the scrap, welding up the 'spit' and strongly tacking it to the hull. 45 mins for the actual rollover
    This was working alone.

    It looks a bit 'Rube Goldberg' but you can see in the shots where the hull has been blasted and primed and dragged outside, everything cleans up nicely.
    This one was in a very tightly calculated shed space; during the turn, the topsides missed the rafter by about 3mm -1/8th.
    Of course, I claim that it was perfect planning; but It was an educated guess, some accurate measuring and plain old luck!
    I hope that the thumbnails will expand if clicked...
    If anyone is planning on turning a hull using this method, feel free to email me and I can give you step by step detail and a few tips on what not to do ;-)
    It's equally simple with Glass or Composite.Takes a bit longer, due to the more delicate procedure required.

    All the Best...Jack
    Turning the hull.JPG IMGP0141.JPG IMGP0137.JPG IMGP0134 (1).JPG IMGP0139.JPG
     
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  7. Wckoek
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    Wckoek Junior Member

    Very interesting, was that a hydraulic jack?
    I've seen most use a pulley system for larger boats, but not ideal as the turn can be abrupt and dangerous. What I do with the gantry is too, but this is a lighter boat, but the gantry can't hold that much weight either.
    It would be nice to have a method that turn slower.
     
  8. Jack1.0
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    Jack1.0 New Member

    A light truck hydraulic jack and the jack out of my landcruiser.

    I've also used railroad jacks in the past. (mechanical ratchet jacks - sometimes called kangaroo jacks)

    I'm not suggesting this is the only way. There's always a different way ;-)

    But if you have two people on the come-along's, you can roll it mm by mm, very slow!
    In my case when working alone- and having a firm time restraint- I just get on with what I have on hand (2 hands ;-)

    I leave about 3" slack in the restraining come-along, then haul away on the turning come-along. Then back off the restraining cable again and so forth
    Moves it thru maybe 3-5 degrees of arc until thru the balance/tipping point and then it's just letting it down with the restraining come-along.
    Then move the restraining cable (come-along) to the other side to pull it vertical (ish)
    Of course, cut everything free from the strong-backs, so the only weight is the hull itself and head-stocks.
    There's no point in leaving all the head-stocks in.
    You could leave them in of course, but they're not really needed as their job is nearly done. Just leave the ones where the chain follows the hull.
    I only use one gantry or crane. It's a lot less chance of getting an inadvertant force occuring. One lifting element working against the other if that makes sense.
    Any photos you could put up?
    Best...Jack
     
  9. Wckoek
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    Wckoek Junior Member

    I have 2 gantries as I have to have clearance bow and stern, but I lift from the bow side to flip, it was a wood composite boat so I can't have a hole in the hull unlike your build, I probably can do it from the prop shaft though.
    I also work alone on the hull, so this is the only way I can think of at the time, still wasn't comfortable on how it flip, and not sure if heavier hull can be turn this way as well as the crane aren't made to lift much more than that.
    Yours have the additional benefit that the hull can be tilted to work at certain angle, just not sure how to hold the hull without the tube out of a hole.
    I have pictures on my laptop of the setup, but not when turning as I can't operate the camera when turning.
    Btw, is Ganley's design still available for sale?
     
  10. Jack1.0
    Joined: Wednesday
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    Jack1.0 New Member

    Hello again.



    Please see the video link above for another idea how to roll a composite hull. This is just a clip I copied from you tube.

    Just drill through the stem/stern post(s) and set an eyebolt.
    Use a backing plate both inside and out. When finished just fill the hole with reinforced thickened epoxy.

    I've done similar on a Tom Thumb 28 and a Pogo 30 style, both in glass/ply - except I only physically rolled the stern on both. I just let the bows roll on a bed of old carpet and tarps...

    Another option for you maybe? A lot depends on space available.

    AFAIK - Ganley is still in business. Think he lives in the US now ?

    Best...Jack
     
  11. Wckoek
    Joined: May 2016
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    Wckoek Junior Member

    I have seen the video before, and not sure what they used to hold the hull, but then again, it is a very light cruising/racing type of hull as was Pogo 30 I believe, not sure if heavier will crack the hull, or the backing plate is sufficient.
    I drill through the bow just because I am worried about damages on the hull, and anything from there can be fix easier, just that I use chains which turn abruptly, I would have use your idea if I build a mext hull.

    I understand that Mr Denis Ganley sadly passed away from a car accident in 1997, his website is still up, but I couldn't get through their contacts if his estate is still in business. You must have build his design quite a while ago.
     
  12. Jack1.0
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    Jack1.0 New Member

    Sorry, a hiccup in my memory. I was thinking of Dudley Dix.

    Yes, Unfortunately, Denis and his wife were killed in a car wreck. His daughter - Denise? - still runs the business I thought?
    I know that she had some health issues herself, so maybe it's a part time sales situation.

    The hull I used as an example for the spit roast was originally a Hout Bay 33 blown out to 36' that I built around 2000.
    This was 2 or 3 years after the accident, so someone was still operating the business at that point.
    Around 3 years ago a guy called me and asked if I could build a 'Black rose' in aluminum for him to fit out himself, but we couldn't get the timing right.
    He said he'd recently bought the study plans. I just presumed he's got them from Denise. I don't have a phone number, Sorry.

    I didn't build my own boat, I bought it in Langkawi in 1998. Mine is the open transom version. French owner builder.

    Good luck with your project! I'd be interested to see any images you have where your boat is now?

    Best...Jack
     

  13. Wckoek
    Joined: May 2016
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    Wckoek Junior Member

    Interesting, as I am having the hull build in Malaysia as well, and in the process of fitting out, that is easier to have fitting out process made by others, but it is difficult to find builders who build a hull unlike in the UK.
    It was a relatively light full displacement motorboat though, I have a metal motorsailer or trawler on my mind, but a long consideration makes me hesitates that such a project is beyond my current ability, but a light motorboat can be currently practical to use and easier to build and not so common in the market (as a planing/semi displacement type of motorboat).
     
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