80 foot cargo harryproa

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

  1. rob denney
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    rob denney Senior Member

    Those are all 15+ years old designs with bow shape heavily influenced by the then 'common knowledge' that proas sail bow down. While this may be true for proa hulls with rocker, it is not for Harryproas that are rockerless. Consequently, later designs have far sharper bows.

    Harryproa rudders have also improved immensely, within the constraints that they:
    must work in both directions,
    are adjustable in both rake and depth,
    are large enough not to need daggerboards,
    kick up in a collision,
    have no holes below the waterline.
    Proa rudders are trivial problems if some of these are ignored, but we think each of them is more important than the looks of the rudder or the amount of spray they produce. Having said which, we have been continually evolving them and the latest versions are less complex, with less to be hit by spray and waves.

    The cargo proa rudders do all of the above and also contribute to lifting the hull. They are simpler to build than any of the previous designs. It will be interesting seeing how they work.

    Steinar (Harryproa stylist and builder of a 20m in Norway) has gone one step further with a design which does all the above, but is mounted in the hull. The construction is more complex, but the plans include instructions for 3D printed moulds for the difficult bits and for the blade section moulds.

    Steering complexity is also a proa issue we have been improving for 20+ years. Ideally, it is possible t0 steer with either or both rudders at the same time. Further, it is beneficial to steer with both rudders to provide negative leeway to crab to windward to avoid obstacles, get clear wind or sail/motor off a jetty with the wind pushing you onto it. Tillers and extensions work well on the smaller boats, but tend to be fragile and can see high loads as the boats get bigger. Solutions have included twin wheels and various connections allowing the rudders to be linked or not. The Cruiser series take this further by arranging the helm so it can be used either inside or outside the cabin.

    The cargo proa solution is as simple as I could make it. A whipstaff in a socket with cleats to attach the steering lines to, providing all the above options and several more (differential steering between the rudders, locking either rudder, rapid turning while shunting, variable force:steering ratio and the ability to steer from anywhere on the boat, including the lee hull or the deck of the ww hull, which is important for a 2 crew boat tying a 24m/80'ter boat up to jetties. Again, interesting to see what works.
     
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  2. Othmar
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    Othmar Multihulls ...

    Hi Rob, thank you very much for the explanations. It would be nice to see some of these optimisations in detail. Unfortunately, none of the links in your answer work. Your website Harryproa http://www.harryproa.com seems to be closed.
     
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  3. rob denney
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    rob denney Senior Member

    They all work for me, either through the links above or by typing in harryproa.com . Maybe try googling harryproa and click the link?

    Anyone else having trouble?
     
  4. Flotation
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    Flotation Junior Member

    The links work for me albeit a bit slow.
     
  5. redreuben
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    redreuben redreuben

    Worked for me, snappy as. Try turning your computer off and turning it back on again.
     
  6. guzzis3
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    guzzis3 Senior Member

    All fine here. Good to see you posting Rob.
     
  7. rob denney
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    rob denney Senior Member

  8. rob denney
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    rob denney Senior Member

    A fun week playing with the wing. WIP pics attached. The final version will look different to this. The material (peel ply) is not tensioned height wise, the camber inducer will be less ornate (and automatic), the cloth will be sewn, not glued and it won't wrap around the leading edge.
    The wing structure is low cost carbon rods (~$AUS4/m, $1,600 per 50 sqm/540 sq' rig) which we can easily make bigger or smaller and mass produce anywhere. The latest wet out machine makes them easy.
    Each section weighs 4.5 kgs/10 lbs, 45 kgs total per rig: I think this is significantly lower than the equivalent sail, battens, track, cars, boom, traveller and fittings for a 50 sqm mainsail?
    There is plenty of development still required but it looks, to my ever optimistic eye, to be on the right track. Next step is to put it on a mast section and see what we can learn, then start on all the little, tricky jobs. Like raising/lowering it and the telescopic mast, sheeting it and getting it to stack neatly.

    The rest of the 18 month build story including pics, weights, costs, mistakes, lessons, etc is at Cargo Ferry Prototype – Harryproa http://harryproa.com/?p=3788.
    warped wing.jpg Wing skeleton.jpg wrapped wing.jpg wrapped wing 2.jpg wrapped wing 3.jpg
     
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  9. rob denney
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    rob denney Senior Member

    Borrowed a set of accurate crane scales and weighed the bits.

    Lee hull ends incl rudders (2 x 125) and middle (310), ww hull (350), beams (2 x 82), masts (2 x 122), wings (2 x 10 x 4.5kgs) and rudder blades (2 x 32). The toybox and 8m/28' tender were not weighed, but are near enough 150 and 250 kgs each.
    Total is 1,880 kgs/4,200 lbs. Strings, blocks, winches, o/board, safety and nav gear to come, but looks like <3,000 kgs/6,600 lbs ready to sail.
    Materials cost $AUS50,000/$US33,000.
    We have pretty much finished what we intend to do here, are waiting to pack it all into a couple of containers which leave for Fiji mid January. Maybe a month or so to assemble it, then testing/repairing and in service by mid year.
     
  10. oldmulti
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    oldmulti Senior Member

    Well done Rob, we have all learnt something during this build. The sea trials will tell us more about how stiff the glass hulls are and if the rig will require any further development. All good ideas need a little time to refine. I hope the facilities in Fiji will allow you fully optimize the the boat.
     
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  11. BobBill
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    BobBill Senior Member

    Luc.... , this swab has but one question...tacking in harbors might be a problem or not? Rest is fine...Seems to me our harbors are already quite full, so maneuvering is a good...not like one is raveling isle to isle in South Pacific...just curious.

    Am a tacking and Harry fan.
     
  12. rob denney
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    rob denney Senior Member

    So do I! Sounds pretty good so far. SSTI are certainly keen to make it happen and there are plenty of others keen to get on the band wagon now that there is something more than pretty pictures and talk. The glass hulls are stiff where they need to be (between the masts and below the water), not so much elsewhere. Be interesting to see the effects of flex on panel toughness. If the "good ideas" only need a "little time to refine", I will be a happy chappy!

    BobBill,
    Shunting a properly set up proa in a tight space is far less hassle than tacking or gybing: A shunt can be reversed at any time. Unlike tacking, you don't need to maimtain speed to pass through the wind. Shunting is far more leisurely, the sails can be sheeted on as quickly or as slowly as you like. In the event of a drama, the boat can be stopped, and if required reversed.

    What constitutes 'well set up'?
    Rudders which do not have to be raised/lowered and automatically align when the boat changes direction,
    No headsails to raise/lower or furl/unfurl
    Schooner rig on which the foresail is sheeted on first. This causes the bow to fall away and 'slipstreams' the aft sail so less sheeting is required.
    Lightly loaded sheets. We used to do this with the ballestron rig, the wing sails should see even lighter loads. Sheeting on 2 x50 sq m/510 sq' sails without a winch would be pretty cool.
    No dagger board to stall as the boat gets moving
    No overloaded/ballasted windward hull.

    No videos, but the following sums it up pretty well:

    I sailed my 7.5m/25' una rigged Elementarry upwind up the canal out the back of my house. See attached map showing a 20m/66' marker. The distance to sail is about 200m, the breeze is channelled pretty much straight down the canal. John Metza said the following on Multihull Mailing List: "I watched Rob shunt his 25'/7.5m proa upwind up the narrow (35m for most of it) boat filled channel behind his house so fast and easy I thought he must've had an electric motor hidden in the leeward hull. I would've had a very difficult time doing it in a beach cat without stalling, hitting somebody's boat and/or breaking out a canoe paddle. With the exception of a wind surfer, I had never seen a sailboat with a reverse gear before. He could head right for something, then throw it in reverse, back away and bolt off in a new direction under perfect control. I would not attempt it in a cat unless I had a crew and a jib to backwind. There is not enough room to gather speed to tack and if you screwed it up, you have no control so hitting a moored boat or the wall is inevitable. Screw it up on a well set up proa and you sail off in the other direction and try again."

    I have added taking video of close quarters single handed shunting to the prototype 'to do' list.
     

    Attached Files:

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  13. BobBill
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    BobBill Senior Member

    Imagine, sailing along in heavy weather, keel/sloop Ensign...beer in inhand (left); right mitt on tiller, must tack, so we push tiller over and grab sheets...voila, tack, *** in same place...gotta luv it...
     
  14. BobBill
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    BobBill Senior Member

    Beach catting is what currant rig is set for, not a keeler and...forgot one thing..I built this modern MO with easy tzker idea in mind, no surf here, and forgot one important thing...set up time...shoot me....
     

  15. BobBill
    Joined: Oct 2009
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    Location: Minnesotan wakes up daily, in SE MN, a good start,

    BobBill Senior Member

    There is book of a slick ocean Proa that may offer some insight...I have it, but upstairns and just cracked a brew...lazy dodger that I am, so cannot render title...
     
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