80 foot cargo harryproa

Discussion in 'Multihulls' started by lucdekeyser, Nov 15, 2020.

  1. Dejay
    Joined: Mar 2018
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    Dejay Senior Newbie

    Thanks Rob for sharing your fascinating concepts, ideas and experiments openly! As a newbie I really like your designs and have learned a lot.

    Possibly a stupid question: The truss stiffened panels can still be bend into the shape of the hull even if infused on a flat table? I guess they are just stiff enough to resist local bending, but are flexible enough in their full length? Sorry if this is obvious.

    With foam core, I assume the same would not work well and you would need shaped molds?

    The economic comparison of stiffened solid fiberglass vs foam core is really interesting. Plus being able to vacuum infuse on a flat surface. If I understand correctly the composite costs would only be about $28.000 US if you order from china? (plus sails, rigging, motor, safety gear etc.)

    That sounds really amazing. Not just for pacific islanders but the cargo ferry concept could be great for less affluent people looking towards a sailboat as well.
     
  2. Eric ruttan
    Joined: Jul 2018
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    Eric ruttan Senior Member

    Not Rob, but...
    The panels are the shape of the hull. They do not bend 'into' any other shape.
    Robs hulls are, famously,mostly flatish, as many moderns hulls are.
    Foam core works BEST with flat shapes.

    Rob will have to speak to his final costs, but no boat gives you more for
    less dollars than Rob's designs.
     
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  3. Dejay
    Joined: Mar 2018
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    Dejay Senior Newbie

    Ok after looking over the pictures again I finally get the puzzle.
    There is indeed a curved 12m mould for the hulls, sliced lengthwise. It's not a fisheye camera distortion haha. This quarter mould is used for the windward hull and the ends of the lee hull.

    Then the top half of the windward hull widens to an internal shelf / desk surface.
    I wonder if the top sides of the WW hull were also infused in the curved 12m mould?
    And are those shelves wide enough to sleep on? Or does a bed go in an end?

    It's definitely an amazingly utilitarian design!
    Those ribs in the ww hull make my knees hurt just by looking at them :)
     
  4. Eric ruttan
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    Eric ruttan Senior Member

    The build is public and documented in the groups.io group harryproa
     
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  5. Dejay
    Joined: Mar 2018
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    Dejay Senior Newbie

    I checked out that group but I prefer the written up blog version here.

    I'm looking forward to seeing if Rob can apply the methods from the cargo ferry prototype to the C60 or C50, hopefully to allow for even cheaper or easier build or more performance.

    I'd also be curious if the C60 which also has a 12m windward hull could be build with it's accommodation but the lee hull of the cargo ferry. Maybe with folding or detachable ends? Not sure if you'd want to.
    Just noticed the original design of the cargo ferry and orbiter seems to have been planned for a 17m windward hull and much more room too.

    The modularity and simplicity of the design is really brilliant.

    My only "complaint" would be that the half high lee hull looks a bit drab. Maybe adding some sheer to the ends or some kind of decorative styling could make it look better.
    Or maybe add two figureheads, one looking forward and one looking back? There is a guy in the preciousplastic group 3D printing large scale with recycled plastic. Newspapers love such hooks so might add some publicity haha.
     
  6. rob denney
    Joined: Feb 2005
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    rob denney Senior Member

    Dejay,
    Glad you like it. Any more questions, let me know.

    Eric,
    Thanks. A bit more detail.

    The ww hull and tender sides are built in separate curved (in one direction) moulds.
    The angled reinforcement ribs probably would not bend uniformly.
    The lee hull and it's ends were built as flat panels with flanges and slots.
    The ww hull cabin sides are the same mould as the hull, but needed some cuts to get it to curve to match the hull.. The bunks are at each end and span the hulls and the shelf, 1.3m wide.
    Foam cored panels would bend enough for any of the curves on the boat.

    Costs are hard to determine as a) there has been a lot of experimenting and b) I had to buy some extra glass to get a good price. This is now for sale. But I have spent about $Aus40,000/$US30,000 on composite materials to build the hulls, tender (8m/28'), beams, rudders and toybox with enough carbon and epoxy to build the masts. Looks like it will weigh between 3-4 tonnes ready to sail. The sail design is as simple and as lightly loaded as I can make it, so the cloth should not be too expensive. I will probably sew them myself at the Uni makerspace. Deck gear is minimal compared to any other 80'ter (or 40'ter for that matter). The rest of the fitout is the same as any other work boat.

    Unlike the rest of the Harryproas, the cargo proa is not built using Intelligent Infusion (some components were not even infused intelligently:)). It is a mash up of all the easy build/lightweight/low cost ideas I have thought of but not tried. Some worked, and will be included in Intelligent Infusion, some didn't.

    The boat I am building is a prototype version of the one on the web page. To reduce cost (bigger ww hull, survey, insurance, more fit out and safety gear are all required) , it will not carry passengers. Nor does it look as good.
    There is no reason why the C60, either cargo proa and the Orbiter 80 could not share components, as long as the windward hull was from the shorter of the designs.
    Agree about the drabness of the centre hull. We finished the centre section this week: a 12m/40' long, 0.8m/32" high and wide box. Easy to build (4 panels glued together, no jig or strongback required) but utilitarian. Won't look so bad when the cargo boxes are on it.

    The publicity will be starting soon, hopefully the concept will attract enough attention not to need enhancing, although making figureheads, as well as the cargo boxes, from recycled plastic would be cool.
     
  7. Dejay
    Joined: Mar 2018
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    Dejay Senior Newbie

    Ok then. Where does this madness end? ;)

    For example could you put something like 7.5t box truck on the lee hull between the sails? Or an excavator? Or a 20' shipping container?
    I figure you'd need a crane or a loading dock or maybe some kind of smart ramp. And secure the cargo and stay below 10t. But besides that?

    From the pictures it looks like it would interfere with the tender and you'd need a bridge deck that is build lower and on level with the lee hull. Could that still be strong enough and cheaply build?
    And could you temporarily raise the booms on the sails to accommodate a 2.5m high box?

    And no, I'm not sure where I'm going with this haha.

    Interesting, thanks again for sharing. The weight and price is really amazing.

    Do you tend towards the flat panels with flanges or curved moulds?
    Being able to build completely with a shorter flat table in a smaller workshop could be interesting. You could then basically build a cargo proa in a workshop on top of a cargo proa! A self-replicating Von-Neumann proa!

    Do you plan to add insulation to the WW hull living area? Would you just glue XPS foam and a lighter fiberglass panel to the inside wall?
    And if build from scratch for heavy insulation, would you then consider vacuum infusing this as solid fiberglass with XPS as a pseudo-core? Or then just go with structural foam? I assume the latter, but I'd be curious if you see any gains there.

    Oh, one more question: Can you estimate how much electrical input power you would need to drive a mostly empty cargo ferry at about 6 knots? Maybe assuming you'd have a separate and optimized motor and propeller besides the tender.
     
    Last edited: May 6, 2021
  8. rob denney
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    rob denney Senior Member

    It would be dangerous if you were caught aback. Same as stays on a stayed rig proa. The deck is not built for large point loads, which would make it tricky as well. Otherwise, apart from on/off, it is possible.

    The only freight on the bridge deck is stuff which is too big for the cargo boxes, such as building materials which would span the beams.
    Not at present, but if it was the only way to move something, then it could be arranged. The purpose of this boat is to move boxes that can be manhandled, not big heavy individual items.

    Depends on the task and the work force. The flat panels with flanges were an eye opener for the middle section of the lee hull. Quick and easy to build, even quicker and easier to put the bulkheads in and join it together.

    This boat will be sailed in warm climes by local people, won't be insulated. Would need to do a cost analysis for hot/cold places, but top of my head, either less laminate and structural foam or more laminate and XPS. The former is probably cheaper and certainly lighter. The latter is tougher.

    Did this exercise (seat of the pants, don't take it too seriously) last week after having a play with EClass electric outboards. Result was: 1hr @ 5 knts less than a kwh of batteries with a 10 kw motor. Apart from playing with the motors, the fun part was discussing with the battery supplier the potential for structural panels with the batteries as core, f'glass each side and the solar panels on top. All going well, this will be how we build the lid for the toybox.

    Fun week, got the bits outside and in position, including the beams. More pics and discussion on
    HarryProa groups.io Group https://groups.io/g/HarryProa, Harryproa https://www.facebook.com/Harryproa/?ref=page_internal and Cargo Ferry Prototype – HARRYPROA http://harryproa.com/?p=3788
     
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  9. Dejay
    Joined: Mar 2018
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    Dejay Senior Newbie

    Thanks Rob for indulging my weird questions. I know the cargo ferry is designed very well for a good purpose. I'm just fascinated by the possibilities of an affordable sailboat transporting medium heavy machinery to an island or to remote coastal regions.

    I imagine a relatively simple removable "tray" out of steel beams could fit into the space of the cargo area and tender and distribute the forces the crossbeams. It could be just be one large bracket between the crossbeams and planks or wider U profiles to the lee hull holding the wheels of a truck.

    So do I understand this correctly as a non-sailer: the dangerous part would be the wind shifting and the sails suddenly smashing into the cargo?
    But this would not apply if the sails could be "reefed upwards"? (although that would reduce available sail power)
     
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