Crossbow fl

Discussion in 'Sailboats' started by Doug Lord, Jun 21, 2012.

  1. Doug Lord
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    Doug Lord Flight Ready

    I'm about to build the spinnaker trough for the boat. Basically, it will be carbon and shaped like the one below(except centered just ahead of the forestay and it may be material instead of a solid straight tube). My question is what diameter do you think it should be for a 120 sq.ft. spinnaker? I'm thinking about 8"?

    click-
     

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  2. Doug Lord
    Joined: May 2009
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    Doug Lord Flight Ready

    I am definitely going with the smaller rig for right now. Later I will experiment with the bigger rig and movable ballast system. This will allow me to focus on the details of the boat and the DSS foils. The interesting thing is that the boat will not be able to be sailed in winds over 10k unless the DSS foils are working the way they are designed to. So it will be a fun experiment!
    These are the (probable) final specifications:

    =================
    Non Trapwing version--

    Specifications: (changes are to be expected)
    LOA-14.6'
    Beam- 4.75'
    ---at waterline-3.75'
    Sail Area-(boat will use a carbon A Class wing mast from Matt McDonald/ Falcon Marine LLC ).
    --upwind- 92.5 sq.ft.
    -- downwind- 192.5 sq.ft.
    Weight-sailing weight w/o crew- 170lb which includes:
    --a. hull, rig, foils-123lb
    --b. ballast bulb 47lb.
    --c. Max Crew weight: 250lb
    All up sailing weight including crew-420lb
    DSS Foils: each 1.63 sq.ft.( 6" X 39") 6.5/1 aspect ratio, Welbourn section.
    -------
    Ratios-
    DLR=(smaller better)
    a.Windmill-93.95
    b. Crossbow-60.25
    SA/D=(higher better)
    --upwind-
    a. Windmill- 28.68
    b. Crossbow-26.37
    --downwind
    a.Windmill- 28.68
    b. Crossbow- 54.89
    SA/ton(2240) : ( Note: rule of thumb says 500 sq.ft. per long ton required to plane. It is well known that the Windmill planes-and early compared to many boats)
    a. Windmill- SA/ton=493.85
    b. Crossbow-
    --Main +jib- SA/ton=493.3
    --M+J+asy spin-SA/ton= 1023.36

    This is very encouraging because I raced Windmills for years and it was a great boat to sail. It was also quite fast for its time-(especially in light air against Flying Dutchmen!).
    The upwind SA/D is very close but Crossbow is much better off the wind. The Crossbow DLR is substantially better. I wanted to try to tweak the non-turbo(minus the Trapwing) version of Crossbow to get as close to a Windmill as possible while still retaining Crossbow's self-righting capability which I think I have done. The Crossbow will carry 47lb of lead at the bottom of the daggerboard and should be self-righting with the crew in place. It should recover from a knockdown with little to no effort from the crew. A block and tackle on the boom(maybe the vang?) would be used to mostly retract the board allowing the boat to still be sailed off a beach.
    I'm pretty well convinced after doing the design work yesterday and today that going with the "simple" version to start with is better for me-all things considered.

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  3. CutOnce

    CutOnce Previous Member

    8" should be big enough, depending on how many patches/loops you put on the sail. Two points with the bottom being a loop should fit fine, but a three patch system with two loops might bunch up a little. If you are having the kite made, specifying a low friction coated fabric can ease the problems with the chute tube tremendously, even if at a slight weight penalty.

    The real challenge is the turn and friction on the turn. Lots of McLube and putting a hard, low wear surface at the turn is critical. The SwiftSolo folks (and I on the Falco) find our biggest problem is friction on the turn where the halyard/kite wraps around almost a 60 degree corner. The bigger the radius of this corner the better, and something hard like carbon-saturated epoxy is better than a softer turn with microballoons and filler.

    I'm glad you are sticking to your guns regarding the available tube/rig and reduced development risk project. This kind of firm project management is critical to keep you on track, on schedule and costs under control. Some people have the resources to keep moving the goalposts further away financially, but getting to the end zone is more important.

    --
    CutOnce
     
  4. Doug Lord
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    Doug Lord Flight Ready

    Thanks, Bill. I like the Viper system with, what appears to be, a ball bearing roller but this way is simpler. I used this and McLube on the RC spinnaker troughs. The tube is likely going to spew a lot of water in the self-draining cockpit and thats ok if it's not splashing my feet. May work out a more direct drain system if necessary.
     
  5. Doug Lord
    Joined: May 2009
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    Doug Lord Flight Ready

    Crossbow fl and EPS

    Here is some info that may help others considering using "Styrofoam" to build a boat-from Universal Foam Products: http://univfoam.com/


    "The term STYROFOAM is often used to refer to expanded polystyrene even though the materials are completely different.

    STYROFOAM™ is a registered trademark of the Dow Chemical Company (“Dow”) or an affiliated company of Dow. The trademark covers a full range of extruded polystyrene building products used primarily for insulation of floors, walls and roof systems. The insulation panels are commonly referred to as “blue board” in the construction industry.

    Dow Chemical’s STYROFOAM Brand Foam also covers a full range of foam products for the floral, craft and special events industries. These products are available in sheets, blocks, spheres, cones and many other shapes. They are available to the consumer from major craft and floral retailers throughout the country.

    Expanded Polystyrene (EPS), is the generic industry name for a white rigid material made by expanding polystyrene beads with steam and bonding the beads together under pressure in a block or shape mold. EPS is used in the construction industry for insulation and void fill. It is also used in a variety of packaging applications including coolers, wine shippers, molded end caps and corners. It can be cut into an unlimited variety of shapes."

    --------
    For Crossbow fl, I am using 1.5 lb. per cu.' EPS cut to shape by the local supplier , Rockledge Architectural, Sharon Dixon, owner. I considered X-EPS(extruded polystrene/Styrofoam) but it is expensive and only available in 2lb. per cu.ft. density and 4" X 8' X 3' sheets-too heavy for this little boat.
    I remembered that Hugh Welbourn had built a scaled down Wally with an overall length of 27' using "styrofoam". His foam was actually EPS and nominally 1.87lb per cubic ft..
    He said it has worked well as a DSS test boat(but don't kneel on it!*) and continues to race 5+ years after it was built.
    I called Universal Foam to get the maximum temperatures for a surface with EPS under it:**
    1) 167 degrees for several hours,
    2) intermittent temperatures of 180 degrees.
    Other sources have said don't exceed 140 degrees.
    The boat will be cut out of two major blocks of foam and one smaller block and a couple of 1" sheets-all bonded with a spray foam stuff that Sharon says work well well at bonding EPS.
    * For the cockpit and aft deck I'm going to use 1/4" Okume(probably-or 6-18lb foam) carbonated and bonded to the EPS. Side decks are not to be walked on -the waterline beam is too narrow to allow that.
    ** My infrared laser thermometer just came in and I measured the surface of my metalic red Hyundai: 155 degrees!! The whitish concrete next to the car was 131 degrees. Ah, I guess the boat will be white.......
    -------
    To layup this stuff it is recommended to use a mixture of 50% microbaloons and 50% epoxy resin as a first coat(don't let it set up) followed immediately by
    the carbon layers. Some surfboard manufacturers use(or used) spackling compound. Very labor intensive and contains water.
    Still waiting on the final ,definitive cost estimate from Matt at Falcon.
     
  6. Doug Lord
    Joined: May 2009
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    Doug Lord Flight Ready

    News Flash: the best DSS video yet done : http://vimeo.com/45635108

    From Foilers! http://foils.wordpress.com/

    New DSS website: http://www.dynamicstabilitysystems.com/

    ===================
    ================
    The instructions with the infrared thermometer say the same thing, Paul. This thing is supposed to have (and does have) adjustable emisivity for highly reflective surfaces. So I don't get putting black tape on the surface in the hot sun-it seems like that would give an incorrect temperature? I can see the black tape if you're measuring a machine or something inside a building but it doesn't make sense to me on an object in the sun.... I guess I'll call them.
     
  7. Doug Lord
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    Doug Lord Flight Ready

    This is an answer to an e-mail set of questions from Matt McDonald(Falcon Marine) in order to help him understand more clearly exactly what I'd like him to do-which is substantially less that what he thought he had to do. I'm going to do (back willing) much of the little detailed work of making and installing the DSS trunks, daggerboard trunk, transom bump, two piece center deck, spinnaker tube and trough, cockpit drains etc. It will stretch my capabilities physically to the max but I think I can do it.
    He is in the middle of getting several of his new F18's ready to ship to California on the 25th. I saw the boat yesterday and it is first class.

    =======================

    Matt, thanks for the questions. I hope this answers them all. Any clarification can easily be made in a few minutes with the model:
    1) How do we create inserts for foils, spin, bag, pole etc?
    ANS: You don't-the styro block will be delivered with all trunks installed, transom bump installed with gudgeons, all outside corners radiused and inside corners fitted with a balsa or foam "fillet"so that every thing is ready to be carbonated. You should have no work related to any of these items.
    ---------------
    2) How do you want joints and seams handled?
    ANS: There should be no joints or seams other than the carbon overlap and that would be just "best practice". I can better understand this question face to face.
    ---------------
    3)In what condition will block be delivered so we can laminate deck and hull w/o making any hold fixtures?
    ANS: The styro block will be delivered as in #1 above. The hull and deck are one piece with the exception of the "deck" piece I supplied with the model: I'm building this-you don't have to do anything in regard to this center deck at all. I've pretty much decided to do it in two pieces which I can explain better when we get together-but nothing related to the "deck"(separate piece) will be included in your estimate. I will also install the 1/4" or 3/8" "deck" in the cockpit and it will be ready to carbonate when you get it.
    ---------------
    4) How do we do the deck so it is not puncture or dent prone?
    ANS: The side decks will be the "crews" responsibility to prevent anyone walking or sitting. The cockpit deck and raised aft deck as above. You have no responsibility or effort required here at all.
    ---------------
    5) How do you envision hull to deck seam being laminated and then finished?
    ANS: Answered in #3 above.
    ---------------
    6) Level of finish?
    ANS: The best answer, for now, is the best possible for approximately $1000 after lamination is complete. Foils and center(black deck on model) are not to be finished.
    ==================
    I've tried to be very specific here but lets get together and go over this as soon as its convenient for you. I will be doing a lot more of the detail parts than I led you to believe so this ought to help a lot in trying to estimate what is, in essence, just a carbonation job with limited finishing.
    E-mail me when we can get together-don't think it will take more than 20 minutes.
     
  8. Doug Lord
    Joined: May 2009
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    Doug Lord Flight Ready

    Crossbow fl-split deck

    Pardon this illustration-I'm not good at all with "paint". I'm trying to illustrate that the deck will be split into two pieces-both made of carbon.
    One of the main reasons is to make the cockpit cooler. Also allows good access to the spinnaker. For winter the space can be sealed. Matt still has the model so I'm not yet able to make the change on it but I will when I get it back. For now, this is the best I can do but you should get the idea:

    click:
     

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  9. Doug Lord
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    Doug Lord Flight Ready

  10. ancient kayaker
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    ancient kayaker aka Terry Haines

    Looks more like extremely beaten up aluminum to me!
     
  11. Doug Lord
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    Doug Lord Flight Ready

    POST #1 of this thread:
    ====================
    Never truer than now! I'll be tied up for several months soon for an operation.
    So far it looks like just a delay in the project not the end. We'll see.
    In the mean time, I'm going to try to finish out the model and video a capsize test using the wing.(Though my ability to accomplish anything right now is severely limited)
    =================
    Also, I'm going to take Tom Speers advice and stick with the original rig and go one step further and do the Trapwing System rather than a "low power version". The more I've been confronted with my own trouble the more convinced I am that I need to prove that the Trapwing movable ballast system is viable. It will potentially help so many people experience performance planing monohull sailing in a self-righting boat that meets or exceeds the safety standards of disabled sailboats currently produced. At the same time allowing people to experience greater performance than is currently available in any self-righting singlehander used for disabled or physically restricted sailing anywhere. If the Trapwing system can be proven it will change disabled/physically restricted self-righting dinghy design for good in a way that could allow a large group of people to experience singlehanded performance sailing in a way that is just not possible now. But this is a tough nut to crack and there is a lot of work and testing to be done to bring this potential to the real world-but I believe it can be done and more-should be done!
     
  12. P Flados
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    P Flados Senior Member

    Keep plugging Doug and good luck with the medical stuff.
     
  13. Doug Lord
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    Doug Lord Flight Ready

    Thanks, Paul. I've had some time in the last couple of months to reflect a lot on this and I've come to the conclusion that this concept is worth whatever it takes to prove it works and works well. I believe in it more now than ever and I hope I can follow thru.....
     
  14. Doug Lord
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    Doug Lord Flight Ready

    As I was getting ready to get this thing built I mocked up the center seat to test it for comfort. What a surprise I had! The original design had the seat so it was up off the cockpit sole about 10 inches but because of my injury I could not sit comfortably-either the seat had to go up or my feet had to go down. Now, the cockpit sole is above the wl and designed to be self-drainiing after a knock down so molding in recesses for my feet to go lower would create a pocket or pockets that would fill with water-no good. Another consideration is that after my op this might not be a problem except for one thing: most of my sailing life I have sailed with the tiller/ext. tiller in my aft hand and the mainsheet in my forward hand. I'm very comfortable with that arrangement and not at all comfortable with the "normal" sit-in arrangement that I started out with for this boat. I have to be able to stay seated w/o rising to my feet to change sides so what I'm working on to allow me to sit most comfortably(and a bit higher) is some sort of rotational seat that would allow me to slide around from side to side.
    There may not be enough room but here is the basic idea-any thoughts would be welcome:
    UPDATE- problem with this seat idea is that people w/o the use of their legs might be compromised unless there is a way to slide by hand.

    click on image-
     

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  15. sharpii2
    Joined: May 2004
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    sharpii2 Senior Member

    You could borrow an idea from Gary Hoyt and build a swiveling seat on an upside down 'L'. The vertical arm acts as a rotating mast to which the horizontal arm is joined. The seat itself is attached to the outward end of the horizontal arm.

    Some way to lock it, once it has swiveled over to the desired side would be a good idea. That could be accomplished with a simple hook and pad eye.

    The seat itself could rotate and lock as well, so it can have a back on it.
     
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