around in pocket, I I think so

Discussion in 'Projects & Proposals' started by WindRaf, Oct 2, 2014.

  1. Manie B
    Joined: Sep 2006
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    Location: Cape Town South Africa

    Manie B Senior Member

    The water in the keel worries me because your entire water could get contaminated which would be disastrous, that is why I have all my water in ten liter containers.
    I will post more videos soon of my balanced lug sail on Fargo, I prefer simplicity and so far I am still believing it is the answer for the Southern Ocean.

    But once again we are faced with the dilemma that until we build a 3m boat we will never really know how she performs. That is why I am so committed to building my TEN - just simply HAVE TO KNOW ;)

    Just going thru an incredibly difficult time at work but all will be back to normal end October and then I can get back to my garage again !!

    good video - must see
    https://www.youtube.com/watch?v=WmgwF-d4i_U&index=12&list=WL

    enjoy
    :)
     
  2. WindRaf
    Joined: Oct 2014
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    WindRaf Senior Member

    Mannie B,
    keel disaster?
    What is the problem?..under the berth must put 50 liters of wine! :). ..italian wine of course!
    Do you know? the ration of wine on the caravels of Columbus was 2 liters per day, for each.
    he he he
     
  3. WindRaf
    Joined: Oct 2014
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    Location: Italy

    WindRaf Senior Member

  4. WindRaf
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    WindRaf Senior Member

    a cat with the center drift forward it is impossible to send straight if you are not always handle the rudder
     
  5. Manie B
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    Location: Cape Town South Africa

    Manie B Senior Member

    ;) in my young days I sailed a Laser ;)
    in my heart I am a dingy sailor
     
  6. sharpii2
    Joined: May 2004
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    Location: Michigan, USA

    sharpii2 Senior Member

    Hi Windraf.

    One of the problems with a very high displacement is that you need a sizable sail plan to move it.

    Based on your drawing, I calculate only 5.77 sm for your entire working sail plan. This is smaller than just the main sail for mine.

    And my boat is a much lighter all up displacement.

    A problems with storing the drinking water in the keel are two fold:

    1.) that becomes unwanted buoyancy way down, once the fresh water nears exhaustion, and
    2.) the water can become contaminated by even the smallest breach in the keel.

    With my design, the fresh water is stored in 2.0 liter bottles. Each bottle will have a rubber band around its neck. Once emptied of fresh water, the rubber band will be removed, and the bottle will be filled with salt water and put back. This is to insure the ultimate stability of the boat.

    Another thing to consider about the rig is that the voyage is likely to be mostly down wind, with some reaching, and tacking used mainly to get in and out of harbor.

    The Bermudan rig is by far the most popular for this kind of vessel. I think a mast head cutter would probably be best for your boat.

    I think you need at least 10 sm for your boat. Even this gives you a single digit Sail Area/Displacement (S/D) ratio. Your present rig has a little more than half of that. It may hardly move in even moderate breezes. In near calms, it might be glued to the water.
     
  7. Steve W
    Joined: Jul 2004
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    Location: Duluth, Minnesota

    Steve W Senior Member

    Im done trying to dissuade you guys, i do understand the design challenge aspect of what you are doing and as a guy who has actually designed, built and sailed a number of boats over the years i well understand what is involved.
    I do own a boat that has a 12 gallon water tank built in to the keel sump (using the sump walls as the tank), no one with one of these boats uses them anymore but it is because they have a bolt on keel that can allow seawater in around the bolts. If it was not for that it would not be difficult to make it safe and is a good location for the weight. Batteries in the keel can also be problematic should they ever get flood, but again it is the best place for the weight so well worth figuring out a sealed, vented compartment. One of the big challenges with a 10ft boat is that because they will be so slow you have to carry proportionately more supplies than a boat even just twice the length for a given passage. Webb Chiles has recently arrived in New Zealand on a 24ft uldb that he bought out of our local racing fleet. I actually weighed one of these boats on a hanging scale at just over 2000lbs dry boat and yet he was able to carry the stores needed and still make fast passages. With all boat design but even more so with small job specific boats you are working with a design spiral where every choice effects every choice. The shorter the boat gets the slower it is so the longer the passage times so the more stores you need to carry so the slower you go and the longer the passage times and ---------------. Has anyone tried more of a dinghy style boat for this type of boat? The 12footer i mentioned in an earlier post that I saw in New Zealand had twin keels so more of a dinghy hull, but I don't remember anything more about it.

    Steve.
     
    Last edited: Oct 14, 2014
  8. WindRaf
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    WindRaf Senior Member

    sharpii2,
    I think you did not understand the philosophy of my project.
    The boat that I'm drawing is not heavier than yours, only has more cargo capacity.
    This means that before a long navigation can store more food and water. After 2 weeks your boat and mine has the same weight.
    The fact that the keel there are 200 liters of fresh water does not mean that there is only this one, and must drink it all.
    I could have written: in the keel ballast is seawater, but already you have to fill might as well put fresh water.
    The advantage of the water in the keel is that it is, first a large stock of emergency, and second is easy to empty it when you want to pull the boat ashore, or tow it behind the car.
    The sail surface of the base is 6 square meters. It 'a right fit for an ocean-going ship of 10 ft, calculated by the plane at the waterline. You can also add a gennaker in light winds and easily get to 10 square meters.
    But what matters is the efficiency of the sails, rather than extending them.
     
  9. WindRaf
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    WindRaf Senior Member

    Steve W,
    yes, it is the true paradox: more the boat is smaller and more must have ability to load. If someone thinks load on a 10 ft the same amount of food and water that is expected on a 20 ft, will die of hunger and thirst.
     
  10. Steve W
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    Steve W Senior Member

    Any of you guys considered a Baelstron rig, (the British made Aerorig was an example) It is unstayed which would be very easy to do on your boats, is very efficient upwind and down without extras although it could be adapted to carry a gennaker. Since you will be mostly downwind it could work very well as it really shines at getting that headsail projected and controlled. Just a thought.

    Steve.
     
  11. WindRaf
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    WindRaf Senior Member

    Steve W,
    my opinion is that Balestron is the complication of the simple things. I do not see any advantages about him.
     
  12. Steve W
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    Steve W Senior Member

    Actually it is a very simple rig and that is one of its advantages, especially on a very small boat. Unstayed is simple, a fixed boom is very simple, a big advantage is it is a balanced rig so sheetloads are very small so even large boats only use a 2:1 mainsheet. As you know running downwind with a conventional sloop rig the headsail is an exersize in futility whereas with the baelstron you have the headsail projected out opposite to the main and perfectly under control, also of course with the rig being unstayed you can have the boom much further out, in fact square across the boat. In the past with larger boats these rigs were prohibitively expensive to buy but on a tiny boat it would be as cheap and easy as any other rig if you built it yourself. Eliminating stays increases reliability.

    Steve.
     
  13. WindRaf
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    WindRaf Senior Member

    Steve W,
    with the wind abeam the Balestron brings the sailing center amidships, instead of forward, and this is very bad for the stability of the route.
    Also the ones I've seen have exaggerated oversized mast to withstand the stresses inherent in this solution.
    With a self-tacking jib you have a single sheet also with a normal equipment.
     
  14. sharpii2
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    sharpii2 Senior Member

    Steve.

    The uldb has its own problems. Not to say it is not capable for the job, But it will probably require a more sophisticated self steering arrangement and may actually be a rougher ride. Plus there the possibility it may not hold together for the whole voyage.
    with proper re-enforcing and the right equipment, it will do. And you are probably right that it may be less expensive than a boat that is deliberately designed to be short for the job.

    But I think you are wrong in saying that the speed will be diminished in an ever winding spiral. This is because of the concept of hull speed. As long as the all up speed of the boat is kept well below 1.34 (LWL)^0.5, in kts and feet, it will take little power to move it. The likely speed is going to be around 3.0 kts, with it sometimes reaching 4.0 kts, but often doing less. With adequate wind/sail area, the actual D/L doesn't matter much for this performance range, be it 300 or 1,000.

    The smaller boat, with a long keel, may actually have a more comfortable motion than the much longer, lighter speedster, as the long keel dampens the roll better, and the vastly greater D/L moderates the heave motion.

    10 ft is still gosh darn short. A length in the mid teens would probably be better. But the challenge is 10 ft. And, IMHO, though short, this seems at least somewhat within reason.

    I once made a rig similar to the Baelstrom, or so-called swing rig. I was a teenager then, and I had never heard of it. The one I made had a Boom which crossed the Mast, like a lug sail, but had no yard. The sail was split where it crossed the mast, and the aft portion was laced to it.

    It was surprisingly effective up wind, despite being made out of cheap materials (see second attachment).

    The problem with this sort of rig, on a very heavy ten footer, is that the yard and mast would have to be quite long, in relation to the boat, to provide adequate SA. To keep the Boom length within reason, the mast would have to be quite tall. To get it this tall, and not use any standing rigging, will require making it of carbon fiber. Designing and building such as mast is the job of a highly paid specialist. If the mast is ever broken, a new one will have to be custom made and shipped to replace it.

    The short, stay supported rig I chose has its own problems, such as the very long gaff, but I think its short enough to be made out of wood and be more than strong enough.

    Since the voyage is likely to be almost entirely down wind, a square sail may not be too bad of a choice. Such will be paired with a mizzen mast and sail. With the Square sail full, the boat will be balanced to stably sail down wind at an angle, just as it would with the jib and main I drew (see first attachment).

    With the main reefed, and the mizzen full, it would be able to sail up wind, at least begrudgingly.

    The Boom and Yard could then be well secured to the mast, at their center lengths, and far harder for the sea to wrench free, in the event of a capsize.
     

    Attached Files:


  15. pdwiley
    Joined: Jun 2008
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    pdwiley Senior Member

    John Riding in the 'Sea Egg'. I have a copy of his book.

    As you say, he died. Reading the book tells you he didn't have a lot of fun before that point, either.

    At least he wasn't idiotic enough to try the Southern Ocean route. Anyone thinking of trying this better plan on skipping Australia en route or not count on their voyage continuing. We have & will stop vessels considered grossly unseaworthy from proceeding without repairs and in a case of a vessel that small, I can't see that there is any repair that could rectify the fundamental defects.

    Bit of a moot point though as I doubt anyone in a 10' boat leaving, say, South Africa, is going to ever reach Australia alive & in one piece, let alone be willing to continue on to South America.

    PDW
     
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