Trailerable sportboat weekender?

Discussion in 'Sailboats' started by Steam Flyer, Aug 4, 2008.

  1. Wynand N
    Joined: Oct 2004
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    Location: South Africa

    Wynand N Retired Steelboatbuilder

    Deepsix,

    The lightning 18 will be a production boat produced in the heart of the Free State for people like you and me :cool:
    As said before the design is done, materials already bought for plugs and moulds and within the next two weeks tooling will start on her. Just the 43 keeping us a bit tied up now, but as soon as the carpenters move in, I have my crew available...

    Here are a few stats about her in the meantime to brew upon;

    LOA: 6000mm
    LWL: 5780mm
    Beam: 2133mm
    Disp: 510kg Light ship condition, 830kg Max loaded condition (4 x 80kg people)
    Ballast: 250kg
    Draft: 300 - 800mm
    Sail area: 17m sq
    Prismatic Coeff: 0.47
    Disp to length ratio: 74 light ship condition, 121 loaded condition
    Sail area to disp ratio: 27 light ship condition, 20 Loaded condition

    The keel is a high aspect ratio unit using a naca 63-010 foil with the ballast carried in a bulb at the bottom of keel - the keel is a drop down unit and be raised with a simple winch system.

    The rudder is balanced spade unit and fixed. The cockpit is a spacious and open at the transom. Sail plan is a masthead sloop with high aspect main and large genoa. The cabin has space for two bunks only.

    Looking at the hull you will notice that she has very flat buttocks with a wide and powerful stern and she should be a flyer down wind with definite planing tendencies under the right conditions. To counter act the wide stern and some accidental broaches, the bow entry is quite full with a lot of buoyancy.

    The beauty of this little boat is the fact that she is trailerable, only 510 kg to tow and a small car can handle that and with the keel raised, launch as easily as a ski boat and best of all, affordable:cool:

    I attach a very basic hull line drawing of her to give you an idea how she will look. Note the waterline shown is to max displacement. The provisional drawings were drafted on computer but the plans drawn on my old beloved drawing board

    Ps; I am considering having a transom hung rudder for production units...
     

    Attached Files:

  2. deepsix
    Joined: Dec 2007
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    Location: SA

    deepsix Senior Member

    Wow Wynand, I love it. There are a whole bunch of new designs around of this size, this seems to be on the more conservative end, something like a modern H19. We desperately need something like this in SA.

    I love the vertical lifting keel, trailering is a breeze and they are structurally strong. I have found that a transom hung rudder that fits into a sleeve is the best rudder solution. The rudder can be slipped into the sleeve quickly rather that fighting with pintles and gugeons when the keel is up and the boat is unstable. There is also no risk of the rudder hitting the ground with the low trailer, and you can have a deep rudder for conditions when you need it and lift it to reduce WSA at other times. This is what I have on my boat and I love it.

    I am a interested in your choice of the masthead sloop sailplan, I feel that fractional rigs with a ~105% jibs are so much easier to handle. With a large roach on the mainsail light air performance is reasonable too.

    Masthead asymmetric spinnaker on a retractable bowsprit?
     
  3. Wynand N
    Joined: Oct 2004
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    Location: South Africa

    Wynand N Retired Steelboatbuilder

    Yes Deep, I kept it a bit on the conservative side regarding appearance, but I had found over the years that moderate has a longer shelf life than radical and hence a broader appeal in general.

    That said, the hull is rather flat on an even keel, but as she heels, the waterline lengthens and the underwater profile get "alive" if I may say so. The reason for that was twofold - high initial form stability and of course to get her to plane in the right conditions...if she slams a little bit, that's par for course and will add to the excitement :cool:

    I like your advise about the rudder on/in sleeve and I have an idea how your may look and work, but if you can email (nortje1@telkomsa.net) me a sketch it would be much appreciated.
    As for the fractional rig - the production run will have an option of a 7/8 fractional rig for the more racing orientated amongst us. I am considering adding a retractable bowsprit - again as an option - using an aluminum unit that get fitted under deck in stem after the hull is popped from the mould.

    BTW, where are you based in this funny country of ours :confused: Perhaps you can have a sail with me on the first demo unit fresh out of the moulds when its time come:cool:
     
  4. deepsix
    Joined: Dec 2007
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    Location: SA

    deepsix Senior Member

    I dont have any pictures of my rudder sleeve, but the attached pictures give the basic idea. My rudder has a tendency to ventilate when pressed hard, but I think that the practical benefits outweigh the performance benefits.
    Photo references : Swift Solo, Columbia 30, Phils foils.

    Im in Joburg, I would love to have a ride on the new boat when it is done.
     

    Attached Files:

  5. Paul B

    Paul B Previous Member

    Nice to see someone working on this type of boat. They are a lot of fun.

    I think you should do a bit more research before you begin.

    Masthead rig with large overlapping headsails is the wrong type of rig for this type of boat.

    Overall your design is too flat athwartships, very 1970 thinking. Years ago people learned this was not an advantage for planing, and in fact this shape is later to begin planing than a more semi-circular shape. In light air this shape will be glued to the water, and in chop it will pound.

    Take a look at Steve Thompson's site (http://www.tboat.com/), especially the photos of the hulls under construction. You'll get a good idea of what a modern planing keelboat should look like.

    If you are going to put forth the effort to do this you might as well start in the right direction.
     
  6. Wynand N
    Joined: Oct 2004
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    Location: South Africa

    Wynand N Retired Steelboatbuilder

    Paul B,

    Thanks for your comment and link. However, if you read my above post, you will see that the word conservative comes to mind and is exactly what I intended. This boat is aimed mainly at the family man wanting something small and affordable to go sailing with - and she is not intended for around the cans so to speak.
    That said, I have some preliminary designs - I like radical - that will make your hair stand up, but my country do not have enough potential buyers looking at that type of hull to recoup one's investment.

    Interesting comment Paul - the Steve Thompson's "Cheese 6.5" boat is actually a photo copy so to speak of my Lightning 18, right down to dimensions within a few mm and kgs :cool:
     
  7. Paul B

    Paul B Previous Member

    If you intend ease of use that really says the idea of a MH rig with large overlapping genoas is the wrong way to go. It is much easier to sail with a modern, fractional, non-overlapping sailplan. The fractional, non-overlap rig needs a lot less muscle to use, and there is less heeling moment due to the headsail as the wind gets up. These days the MH rig with large overlap would not be the "conservative" route.

    If you look closely at the Cheese you will note the sectional shape is much more arc-like than what you have drawn. Adding a bit of rocker and softening your turn of the bilge will result in a much better product.

    But it is your project, not mine, so you should do as you see fit.
     
  8. Wynand N
    Joined: Oct 2004
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    Location: South Africa

    Wynand N Retired Steelboatbuilder

    thanks for you input re the sailplan. I will look into it. :cool:
     
  9. deepsix
    Joined: Dec 2007
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    Location: SA

    deepsix Senior Member

    I am a big fan of the non-overlapping frac rig for the following practical reasons
    1. Short foot non overlapping jibs are very easy to tack. 2:1 purchases on the sheets work well but are probably not necessary here.
    2. Although reefing is unlikely, it is easier to reef a mainsail than send someone to the bow to change a jib(light boat in choppy conditions).
    3. Only 2 sails are needed - Cost saving?
    4. Lifespan of sails is alot better
    5. In storm conditions the short overlap frac rigs will sail better with just the main up.
    6. Structurally stronger, chainplates on the gunwale allows a wider stay base than inboard chainplates.

    With all that said, I think that cost and ease of manufactureris the issue here. This is where the masthead sloop comes out tops.

    Hullshape. I think that Wynands hull is fairly similar to the Reichel/Pugh melges boats(see pics), both with flat bottoms and a hard turn of the bilge(see pics). The melges boats do have less rocker and maybe a narrower waterline beam. I was quite surprised to see that the Melges 24 performs just as well as a Thompson 7 which has better numbers.

    [​IMG]
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    Melges 24 pictures from www.sailingcentral.net

    [​IMG]
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    [​IMG]
     
    Last edited: Aug 15, 2008
  10. rapscallion
    Joined: Oct 2006
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    Location: Wisconsin

    rapscallion Senior Member

    I really like the andrews 28. Also look up the t280 made in colorado. I really think there is a nitche here in the 8 meter range. America needs something like the Ross 780 MKIII.

    My dream 8 meter would look like a mini 6.5 meter but would be narrower, an 8'6" beam, so it can be trailerable... a lifting keel... and all the weight in the keel, and no ballast in the hull like the S2 7.9.

    Another boat I like is the cafe 25, the bad points of that boat is not enough headroom and balsa core...


    This is what I want:

    A boat modeled after the Stealth 8 meter, with some minor changes.

    1.) an additional 3 to 6 inches of freeboard and cabin height. I want 6' standing head room.

    2.) Use basalt instead of fiberglass. It is as strong as S glass but cheaper than E glass.

    3.) use polycore, no balsa, and no expensive foams. Use epoxy, no polyester. Use solid glass on the deck parts, no wood.

    4.) get a mast setup similar to the rio hondo 40. I really like the boom, gin pole setup... I don't like the backstay. Modify that platform to accept a square top main. Keep the position of the mast back a ways, so the boat can have a nice big asym without a pole..

    If they can build a MAC 26 and sell them for 20 grand and make money, someone can sell a very sporty 8 meter cruiser for 20 grand and make money.
     
  11. Steam Flyer
    Joined: Aug 2008
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    Location: North Carolina, USA

    Steam Flyer Junior Member

    Agreed on all counts... partly because I grew up sailing racing dinghies with flexy frac rigs and am accostomed to their little foibles.

    A frac rig can develop more horsepower off the wind, and is easier to handle in gusty conditions. The one thing a masthead is better at, performance-wise, is pointing. And it's cheaper to build, a tapered mast is a PITA


    I think the Lightning hull looks pretty good, if built fairly light & stiff it will plane very easily. More rocker will make the boat a little better in a chop and more steady on the helm, although maybe slower.

    The Melges and a lot of other sportboats base their cross-section on an ellipse... a fancy arc, really... and there is probably not all that much difference. It depends on what you want... wide flair & narrow waterline for upwind speed & effective crew hiking; vs wider waterline, more initial stability, and quicker planing.

    My 2c anyway

    FB- Doug
     
  12. alberto88
    Joined: Jan 2009
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    Location: Chonburi

    alberto88 Junior Member

    maybe you can consider boat called a Shaw 650?

    I saw this boat is under construction is in boat yard in Pattaya (CSI Composite Solutions, very useless yard with really bad staff, but the boat is very good).

    Not sure who is own the project, but this boat looks like a great sportboat, just need a new cabin on top instead as right now seem like it is just big cockpit. They finish one already which race in Pattaya, and very very fast that boat.
     
  13. Holiday
    Joined: Oct 2008
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    Holiday Junior Member

    Check out the S2 7.9
     
  14. Steam Flyer
    Joined: Aug 2008
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    Location: North Carolina, USA

    Steam Flyer Junior Member

    ? There are a bunch of them around... a nice racer-cruiser trailerable weekender, but not a sportboat.


    Thanks for the suggestion, I've seen photos of the Shaw 6.5 but never seen one in real life

    http://www.sailinganarchy.com/general/2003/shaw.htm

    Fast but it seems a little extreme. The Shaw and Thompson boats are good ones to learn from, as to the current state of sportboat design & sailing. A slightly shorter rig, slightly more freeboard + a bubble cabin-top...

    FB- Doug
     

  15. mizzenman
    Joined: Mar 2007
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    Location: SWEDEN

    mizzenman Junior Member

    One question from a sollid keel guy please: How much of a hassle is rising the keel on a boat like this?
    Looks easy enough to just pop it up in one minute before entering shalows? But then I heard it was more like 'once in a season chore'?
    What you say?
     
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