around in pocket, I I think so

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

  1. WindRaf
    Joined: Oct 2014
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    WindRaf Senior Member

    angelique, it is obvious that you are here just to deface this thread, like a texas biker, and that you have no technical expertise.

    jamie,
    when you came the first time I have been a friend, and I answered all your questions, technical and otherwise. Now are you too going to get yourself in the band bikers?
    On your last comment:
    do not forget that the ratio of length to width changes drastically with the size;
    - a cargo has a ratio of 1: 6
    - a 50 ft boat 1: 4
    - a boat of 33 ft 1: 3
    - modern open 6.5 m. have a ratio close to 1: 2
    - a modern 10 ft oceanic can have a ratio of 1: 1.5
     
  2. Angélique
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    Angélique aka Angel (only by name)

    No, I just point out some flaws in your planned boat so you won't drown if you better your design with it . . :idea:

    And I point out some twisted nonsense, especially in your responses . . :eek:

    That would make two of us . . :D

     
  3. Angélique
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    Angélique aka Angel (only by name)

    WindRaf, you could have me telling you the same things but in a more constructive and supportive way if that was also your approach to others, and if you could stand some critique given in well meant advices on your ideas and not twisting this into nonsense in your responses if you don't like reality and so can't come up with a proper answer . . :idea:
     
  4. Jamie Kennedy
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    Jamie Kennedy Senior Member

    Sorry I didn't mean to offend. I am a numbers and geometry person not a people person. Very good point about form factor, which is why I think external ballast is needed for a scale model of Santa Maria, if the crew is going to get any sleep and not have to be balancing the boat all the time like they might with a sailing dinghy. But I think that has more to do with sail carrying ability. I still I don't think you can go too wide even with a dinghy if you are also going deep, but if you go deep and narrower as I did you need more external ballast, which isn't good either. My 3 foot Santa Maria is probably too narrow, but I think we also get into trouble over 5 feet. Perhaps not. I've thought about maybe dory shapes also, just wider and deeper for a higher L/D and perhaps fuller in the ends than a simple arc. But I don't think the dory shape works for high D/L ratios. Even when fully loaded banks dory D/L are less than 400. If you truncate the stern and bow you might push it, like a scow schooner. But then I wonder if we need to keep things rounded, like an egg, so it can be wider and deeper and still have resonable flow. Egg shapes are harder to build, but it is such a small boat it might be worth going that way. A plumb sided scow like the Duck folks build might actually work quite well. Lots to think about.

    As I think I said before all of these ideas are worth pursuing. I will try and build some sailing models later this summer. Cheers.
     
  5. SaltOntheBrain
    Joined: Feb 2007
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    SaltOntheBrain Senior Member

    AIT, or "What's the best way to do something really stupid?"
    This topic is making for some...interesting discussions.
    I've spent a lot of time on big water in tiny boats, so the topic appeals to me anyway.
    Can we play a little more nicely together, though?
    Several threads have decayed into sniping sessions lately and I have to wade through dozens of posts about personal qualifications and egos to get to the actual information I'm here to see.
    I no longer participate in any thread involving Boston. Haven't for at least 5 years.
    It makes my visits here much more pleasant.
    I try to help when I can.
    I try to learn when I can.
    I try not to be a bore or pick fights or sing my own praises. (much)
    So, you boys go to your rooms and build 1/12th scale models of what you think an AIT ought to look like and we'll meet at the duck pond and race them when you're finished.
    Loser gets a trophy and has to display it for one year.

    LF
     
  6. SaltOntheBrain
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    SaltOntheBrain Senior Member

    Here's the trophy.

    LF
     

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  7. sharpii2
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    sharpii2 Senior Member

    I don't know if you ever heard of Gerry Spies, who crossed the Atlantic in a blue water Ten of his own design. His boat, Yankee Girl displaced roughly one ton. This gives it a D/L of around 900. He reported no handling problems and was able to sail upwind reasonably well.

    Part of my fascination with this type of boat is to see what the upper limit on D/L's is. My guess is it is around 2000.

    A lighter boat is, of course, usually a faster one. It is more lively too, meaning its pitch and roll movements will be quicker, making it more uncomfortable to live and work on. This can be mitigated to some degree with hull shape, meaning slack bilges and probably a long keel.

    On the Around-In-Ten web site, when it was active, I saw a good number of feasible designs. One was in the displacement range you are talking about. If there was a race and it finished, it would probably have won. This is not because it would necessarily be any faster, but because it would probably be able to carry more sail for its weight and be able to sail at the high end of its speed range more often.

    Another design, on the opposite end of the spectrum, was to displace around 3,000 lbs (1364 kg), giving it a D/L of around 1360. The fellow actually made a 1/4 scale RC model of this boat and tested it on a small lake. It sailed quite well, including up wind.

    I see this type of boat as mainly a water tanker. Fresh water can be collected from rain fall but the rain seems to never fall when you need it. One liter a day rations don't seem realistic when you are baking in the tropics.

    Water makers (reverse osmosis pumps) require a lot of energy. Some voyagers carry almost all fuel and next to no water, reasoning that the fuel allocated to running the water maker is worth many times its volume in water. But this is assuming the water maker never breaks down. If you use this strategy, make sure you bring lots of spare parts, proper tools, and know-how to fix it.

    If yo allotted 150 kg of your 300 kg "consumable" weight budget to water, you would have 150 liters of fw. This you could ration out at an average of two liters a day, giving you a 75 day supply.

    The 200 kg you allotted for the boat includes ballast, I hope. You may be able to get away with as little 60 kg of ballast, if you put it low enough, and plan on stowing your heavier stores, such as water, low in the boat. Gerry Spies used this strategy and got away with no external ballast. He may have had some internal ballast, but if he did it was probably negligible.

    The trick is to compartmentalize your water into bottles or tanks, filling the empty fresh water ones with salt water. This way you can literally drink your ballast.

    With reasonably deep external ballast, you can get away with re-filling fewer of these bottles or tanks, making the boat lighter as the voyage wears on.

    This is the strategy I'd use.
     
  8. sharpii2
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    sharpii2 Senior Member

    With some embarrassment, I realized I made an error in my calculations with my DECAS boats. The smaller ones will be somewhat heaver than I originally stated.

    While fixing this, I decided to raise DECAS MAXIMUS's chine by 3.0 inches (7.6 cm).
    (See first attachment)
    This gives her slightly more volume below the chine than above it, which should allow her to move through the water easier. Her new displacement now comes in at 4351 lbs (1978 kg), which makes her other numbers a whole lot less scary.
    (see second attachment).
    She can now make do with a somewhat smaller rig of about 168 sf (15.6 sm). I decided to ditch the Chinese Lug like main and go with a gaff main instead. This way all of the main is behind the mast and the jib (really just a down wind sail) only needs to be re-sheeted with every beat.

    The rig I came up with has an 11 ft (3.35 m) Boom, an 8 ft (2.44 m) Gaff, and an 11 ft (3.35 m) hoist, netting a SA of 118 sf (11 sm) for the main. A Boomkin, which extends 2 ft (0.61 m) past the stern post provides a sheeting point for this main. The jib goes all the way to the top of the mast. Its tack attaches to a bowsprit which extends 4 ft (1.22 m) past the stem post. This nets a jib SA of about 45 sf (4.18 sm). This combined with the main falls just 5 sf (1.52 sm) short of my 168 sf goal, but I think it's close enough. The mast height had to be limited to get decent angles for the shrouds. As it is, it towers almost 17 ft (5.18 m) above the deck. The shrouds, as does the head stay, which attaches to the stem post, not the bowsprit, attach at bout 15 ft (4.57 m) up.

    Because of the head stay, The latter rung like design of the bowsprit had to be abandoned. It still hinges upward, but is now a mere pole. The jib will be set flying.

    DECAS PLUS PLUS
    ( See third attachment)
    would have a similar rig, but somewhat smaller, due to her somewhat smaller 3807 lb (1730 kg) displacement.

    For DECAS PLUS, the chine had to be raised another 3 inches (7.62 cm), to retain what I consider workable initial stability.
    (See fourth attachment).
    Even with this change, she still has a 2700 lb (1227 kg) displacement.
    (See fifth attachment)

    The actual lines for these boats will be drawn in a 16th century manner, using a compass and a straight edge to draw the parent curve. The bottom curve will be a derivative of that. This is so the hull can be cylindrically developed. I drew a crude sketch of the plan view of DECAS MAXIMUS.
    (See last attachment)
     

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  9. sharpii2
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    sharpii2 Senior Member

    Who did it and when?

    Did his "Mini" have canting ballast?

    If it did, did he have to use an engine to move it from one side to the other?

    How did he ever carry enough stores on such a light boat?

    Did he have an engine powered water maker?
     
  10. Jamie Kennedy
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    Jamie Kennedy Senior Member

    Alessandro Di Benedetto in 2010.
    Probably all of the above, and he didn't need as much stores because he went very fast.

    But since then I discovered Anthony (Ant) Steward that did it in 1992 in a 19 foot semi-open boat East to West, with no auxiliary power other than solar, Capetown to Capetown through Panama. It wasn't non-stop, but very impressive. Boat was sort of like a Flying Scot but with a deep aluminum keel and lead bulb. Interesting fellow. Slept in cockpit. I want to do thin is sort of thing in my Yngling, which is about the same size, but only coastal sailing for now anyway. Got to get it in the water this weekend.

    http://www.dixdesign.com/steward.htm
     
  11. sharpii2
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    sharpii2 Senior Member

    Actually, I don't think this design is silly at all. Even if it was I'd hope I'd point out what was wrong with it and leave the insulting word "silly" out of my appraisal.

    It has no practical use.

    1.) THE HULL

    The basic hull design is of a dead-rise punt, with the plan view bow curve so far forward it may as well be called a dead-rise scow. For its intended purpose, sailing mostly down wind on the high seas, it is not all that bad. The real problem would be trying to sail upwind in any kind of a chop, such as getting in and out of harbor. With this bow shape, it may find it nearly impossible to make headway against a chop. I'd bring the max Beam further aft to get a sharper bow. I would move it back at least one station.

    2.) THE KEEL

    IMHO, needs to be vertical sided. This is for three reasons:
    a.) so it gets a better grip on the water,
    b.) so the ballast can have a lower center of gravity, and
    c.) so it will be easier to fabricate.

    Keeping its air foil like plan may be justified for drag reduction, but will probably not improve its lift that much. This is because it is so long and shallow it will work more like a snow plow than an airplane wing. The upwind side of the keel will not produce much lift, because water on the leeward side will sneak under it, creating more turbulence there than lift.

    Since you plan storing your water there, you might consider giving it a box shape with pointed ends. The portion that is to store water can then be divided into many smaller tanks, with a sump, to collect bilge water, in the middle. This will serve three purposes:
    a.) it will keep the water from sloshing fore and aft,
    b.) it will enable you to refill empty ones with salt water, if necessary, and
    c.) it can isolate contaminate water.

    Making the keel about 2/3 its present width, but giving it a vertical sided box with pointed ends shape, might make up for volume lost due to making the bow sharper. This added volume can be used to house heavy stores (such as canned food) and ground tackle, in compartments designed for that purpose. Some care in designing the cabin sole should be taken to insure bilge water goes into the sump intended and not into these compartments.

    The front end of the keel should be then faired into the bow of the hull, up to the top bow transom, eliminating the bow bulb. IMHO, this bulb actually shortens the waterline in any kind of sea way. Fairing the keel up to the top bow transom also puts a sharp edge in front of the lower bow transom.

    3.) THE RIG

    I find it interesting that you chose a square rig (or is it a Dipping Lug?).

    For the type of voyage being considered, such may not be a bad choice. The only problems are that it is not all that good to windward and needs lots of controlling lines, at least four and probably six.

    An interesting variance would be to have a square sail for the down wind parts of the voyage, and a fore and aft one for reaching and sailing up wind. Both can use the same mast, with the square sail in front and the fore and aft sail, probably a gaff or Bermuda, aft it. The square sail will add area for the down wind parts of the voyage.

    In either case, you have the mast drawn too far aft. It should be no more than about 0.90 m aft of the bow, and probably further forward. this is for two reasons:
    a.) so the fore and aft sail will balance with the hull properly and
    b.) so the mast will not intrude into the cabin space, especially where you will sleep.

    The fore and aft sail should be at least 9.8 sm. The square one could be around 6.0 sm.

    So, these are my opinions.
     
  12. sharpii2
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    sharpii2 Senior Member

    Hurray for both.

    I read Ant Steward's story. Quite a tale. The only criticism I have is that his boat wasn't really an open boat. It was a decked over one with a very large cockpit and no cabin.

    As for the other fellow, how long did it take him? My guess is around 90 days.

    Anyway, I consider a canting keel sailboat, which requires and engine to cant the keel, a motor sailor. I know this isn't quite fair, as the engine on the canting keel boat is really a force multiplier (the boat will sail perfectly well with the keel locked down, but not nearly as fast), but I'm a person who believes in firm boundaries.

    As I have posted on other threads, I wonder if a boat equipped with the same engine, the same amount of fuel, but a shorter rig, would be able to make similar passage times. The theory is that the shorter rig would enable the boat to plane in high winds, and have a hull designed for that purpose, with the engine (with a feathering prop) to motor through the calms and lighter winds.

    My guess is probably not. But still, sailing with the need to have an engine always running, doesn't seem quite right to me.
     
  13. WindRaf
    Joined: Oct 2014
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    WindRaf Senior Member



    I do not agree with even one of your points, for these reasons:
    - The first attribute that must have a 10 ft ocean is the habitat for the skipper;
    - No boat of 10 ft will never go upwind with the sea bad, but could do upwind with all forms of the bow when the sea is calm;
    - Steel ten, being steel, as I have written many times is not suitable for self-construction, but must be done by a professional, and the professionist will have no difficulty to build the keel, 'bulb' including;
    - 'The bulb' extends to 10 ft waterline also with the bow angle, exactly as on ships;
    - As I wrote, the keel-tank has already planned to be divided into sections, although the picture I posted is not seen: it is a drawing showing the interior, not the executive drawing;
    - The sailing rig: the sailing rig is thought to be very changeable, so move at will the sailing center; no boom that beats you in the head, a large area without leaving the center cross of the boat; leave the center cross of the boat means having a side lever that pushes the boat luff when sailing stern; and allows the space for the large autopilot fan.

    ah...the sections position...you losted the essential.
    Try to think better about, and why the Mani'se boat has in general the same geometry.
    Sorry, i can not write here a book of yacht design.
     
  14. Angélique
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    Angélique aka Angel (only by name)

    Sharpii2, thanks for bringing the thread back on track [​IMG]

    I will continue to follow this thread to learn from your ideas and arguments . . :)
     

  15. Jamie Kennedy
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    Jamie Kennedy Senior Member

    RE:
    Very good points. Once I get my Yngling in the water, hopefully this weekend, I might take out some models out with me. I made a lot of models when I was a kid. We really do go out of this world the way we came in don't we. Well I better get on with this before I'm back in diapers, which will be soon enough. ;-)

    I also like the Ocean Explorer / Ooze Gooze / Superbrick scow schooner concept, only heavier. Maybe a daggerboard trunk right to the stem which may double as a bulbous bow. Or if the fixed keel was right in the front, maybe the bulb could be a 10 foot steel rod running the length of the boat to the rudder skeg, or a steel pipe filled with lead, or batteries. Just some crazy ideas, but I think a scow could solve a lot of the directional stability problems associated with a heavy wide boat.
     
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