Thoughts on Hauling 60' Catamaran

Discussion in 'Multihulls' started by FirstLight, Apr 7, 2008.

  1. FirstLight
    Joined: Sep 2007
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    Location: North Carolina

    FirstLight Junior Member

    A project has come our way in Downeast Maine where we are looking to pull a 60' catamaran (60' x 27', 22 tons).

    The quote from the crane company to haul the boat is $22,000 for both ways.. Ouch. Very painful..

    Alternatively, the boat launch area adjacent to the boat yard is over 40' wide with a clear shot to the yard.

    We were thinking of backing a 8' flatbed into the water (padded adequately) under the boat at hight tide and letting the ebb tide ease the cat onto the trailer on the bridgedeck (we would have to build the trailer height up 1' to make sure the hulls cleared the ground).

    Our tides here are 15'-20'.

    Next, we would use large ratchet straps to strap the hull to the trailer.

    After this, we would use a truck to haul the boat up to the yard where we would chock it up for it's 6 moth refit..

    Is ths idea absolutely crazy???

    The only thing that jumps out at me is if the brigedeck is structurally sound enough to support the weight of the boat... Which it seems ike it would be if there was no point loading going on.

    The truck should have enough power as this is a typical load for a big rig..

    Any other ideas out there?

    Any thoughts greatly appreciated...

  2. charmc
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    charmc Senior Member


    You'll need a lot more info to determine if the bridgedeck can support the weight of the hulls. Just the reverse of what it was designed for, of course. The boat is large enough that locating the designer should not be difficult.

    Another approach would be to attach large timbers or steel beams across the trailer bed to support the hulls. Might have to use a single drop lowboy trailer, but you'd be supporting the boat the way it was designed.
  3. FirstLight
    Joined: Sep 2007
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    Location: North Carolina

    FirstLight Junior Member

    Great Thoughts Charlie,


    Unfortunately the designer passed away.. Boat built in '88.

    I liked the idea of adding either two 30' steel I beams to the top of the trailer and supporting on the hulls or perhaps even mounting three or four 30' telephone poles (readily available)....... I suppose I'll have to break out the 'strength of materials' book to sort this out...

    Might not even need to be a lowboy since we are only going 150' with the boat.

    We'll keep plaing with it..

    Thanks again for the input..

  4. charmc
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    charmc Senior Member


    The lowboy suggestion was just to make it easier to get under the hull as it floats; wouldn't need to move the trailer as far out into the water.

    BTW, just out of curiosity, where Downeast are you? I've spent time from Camden to Bath, many great harbors and boatyards up there.
  5. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Used telephone poles and a couple of fat oxen . . .
  6. waikikin
    Joined: Jan 2006
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    waikikin Senior Member

    JP, often cats are better supported by the bridgedeck/underwing, the boats I'm familiar with are usually built in foam sanwich & generaly have 3-4 bulkheads that span the full width of the vessel & are a big part of the connective structure. Often a cage like structure built of rectangular hollow section steel is built with 2 longtitudinal trusses & transverse connectives with bracing & simply bracketed & bolted together, scaffold planks are laid along the top faces to spread the load onto more area & often expanded polystyrene sheet interfaces the underwing to cope & conform to irregularities + save the paint/gelcoat. One thing to bear in mind is that these boats can be quite stiff "platforms" & when traveling over bumps etc & supported under the hulls close to the "corners" of the boat the hulls ride diagonally opposite supports & really need well made cradles molded to the hull shape- support via the harsh edge of an I beam can easily damage a foam boat, if its alu or solid glass its much less an issue. All the best from Jeff.
  7. nero
    Joined: Aug 2003
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    nero Senior Member

    Inter-tubes and or extruded polystyrene.

    The tubes can work as dunnage bags. Guessing that truck size tubes would work well. Tractor size tubes would tend to allow lots of movement in shear.

    Cheap source for steal is mobil home frames. Many times the junior beams can be had for free. They would need to be double up and welded into a sort of double I-beam.

    Also think about the height the boat sits at in the yards. The lower the better for many reasons. Then again if you are going to be doing lots of work below the dwl, maybe a meter up would be better. Just some thoughts.

  8. Spiv
    Joined: Jun 2007
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    Spiv Ancient Mariner

    Just expanding on what Jeff said, we use large polystyrene cubes, about 1mx1mx1m. if you use 6 of them, you would spread the load over 6sqm. If you divide 22ton by 6sqm, you get 3,666kg/sqm which is 0.36kg/sqcm or 5lb/sq". Providing the bridge deck is flat, or that you raise the blocks accordingly to apply an even pressure to the bridgedeck, I doubt you will have problems.
    You could use some polystyrene over wooden choks to protect the hull on the hardstand as well. Make sure you get higher density foam or it will collaps with the weight. Alternatively you could use 8 blocks.
  9. FirstLight
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    FirstLight Junior Member

    Hydraulic Lift


    Quick update..

    1. Thanks for the thoughts on the polystyrene tubes. Load dispersion is an issue to minimize point loading.

    2. I've found a few outfits downeast with hydraulic trailers used mostly to haul lobster boats.. Capacity is well within range of trailer and pads have enough freedom to move about in a way where we can line them up acros the full span of the bridgedeck. Point loading is again the issue.

    3. Final issue that I'm working on is whether or not it is structurally safe to lift boat by bridgedeck. Two designers I've spoken with 'suggest' it should be ok based on how cats are designed. However, I'd rather have something a bit more definitive..

    More to follow...
  10. Sundiver2000
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    Sundiver2000 Junior Member

    If the BD won't support the weight of the hulls, the boat would have probably broken up by now. The flatbed should work fine. You'll need the bearing points to be near the hulls, under the main and aft beams. Use a large enough surface area so you don't crush the lift points. A pair of steel I-beams across the flatbed with wood pads at each end? That's what I'd do. I've seen several boats hauled this way up to a 75' Spronk.

  11. Nordic Cat
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    Nordic Cat Senior Member

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