A Frame Masts

Discussion in 'Multihulls' started by Gus7119, Jan 20, 2016.

  1. brian eiland
    Joined: Jun 2002
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    Location: St Augustine Fl, Thailand

    brian eiland Senior Member

    Another referenced posting from that other subject thread that i had forgotten about.


     
  2. Gus7119
    Joined: Dec 2015
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    Gus7119 Senior Member

    A Frame Diffrent Setup

    A boat for sale on gumtree australia with a diffrent slant on the A rig enjoy.
     

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  3. Gus7119
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    Gus7119 Senior Member

    Aframe different rig setup from 1973

    For sale Australian gumtree
     

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  4. brian eiland
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    brian eiland Senior Member

    That second photo (the one you posted twice is too dim to really make out the mast shape.

    And I don't see that either of these configurations is going to be viable examples for you to consider for your new design?
     
  5. Gus7119
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    Gus7119 Senior Member

    Brian its the same boat the black and white is an largment I made of a photo of the boat on a pin board

    I am going to test an A frame on 14ft cats I picked up 2 for 250 with two sets of sails and only one rig. Both boats are exactly the same zo should show something. Although not looking for speed unless uta heaps slower.
    But Am now going to just get a 35 ft mono and strip the mast winches rails anything I can and use the 11m mast on my cat as the rigging on the boats was renewed only 2 years ago and the boat stripped internally for a refit. So I can pick it up for 1000 bucks should provide most of the deck gear and much more for not much.
    Would love to use an A frame but I didnt find anything helpful from the discussion here as every user that has the rig loved it and every expert all said there was not one worthwhile thing about them. I tend to follow the user in this discussion but as in Australia theirs no real experts or many users of the A frame. Infact this is the first boat Ive seen in NSW with an A frame in 40yrs of sailing.
    Shame the discussion just turned out like all the others so wasnt much help at all. There were a couple of users committed to providing un biased view but mostly there was no comparison data nor any useful relevant information. Just the same old and some even out right BS.

    Hope to one day see an A frame rocking it on a cruising boat as their ment to be not on a race boat as its not a racw rig. Hope somes able to cut through all the crap and get to someone with the design and technical info who has implemented a rig and can provide the useful data all us interested parties are looking for.

    Cheers
    Gus
     
  6. Gus7119
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    Gus7119 Senior Member

    Just quickly brian I wanted to get some info on the voyager as I was interested in the plans for the boat but when I tried to send them a request their contact page doesnt work. And if you cannot con2with the designer then theres no way youll have a successful build. It was the only design I was willing to buy. If you know any way of contacting them please let me know as I want to staet my build this month and have a week or so work left on the model of my build left. Once its finished Ill just go with it unless I can cont4them. Ive tried a feq ways with no luck so any help would ve great.
    And then wed all have a full size boat to get real life data from not just speculation. And Id be more than happy to be the silly bugger who puts his toes in the water first with his dezign as I reckon it lokks great.
    Kind Regards
    Gus
     
  7. waikikin
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    waikikin Senior Member

    Hope the old mono rig goes ok for you, apparently monos have lower righting moments than cats so I hope it's over in section for your use.
    I thought you would to see it through with the A at full size though the stripped mono mast & gear must come at a great discount- the beach cats should be a great test bed for real comparisons. Seeing as you're in Sydney you'll see quite a few A frames in use but for a different purpose set up as sheerlegs on barges for lifting stuff- very simple and reliable setups.

    All the best from Jeff
     
  8. Spiv
    Joined: Jun 2007
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    Location: The Big Wide Blue Brother

    Spiv Ancient Mariner

    A frame Kelsall cat

    Look what I found today in Port Geographe marina, South of Perth.

    I managed to find the contact of the owner, but he has not responded yet.
    I will endeavour to chat with him about his experiences and refer to you all.

    The rig has two rotating wingsections and two mains.
    The booms can rotate the masts and the amount of rotation is controlled so as to have a better foil shape between masts and sails.
    I cannot see reefs, etc, but will ask.
    I suspect one can sail this boat on bare masts only in stronger winds.

    Anyway, I will not speculate any more and will get back with a report if I manage to talk to the owner.
     

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  9. Gus7119
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    Gus7119 Senior Member

    Cool Cat Aframe

    Look how high shes sitting in the water. So much for all that extra weight. She looks like she was built for a single mast with the indent in the coach house fore windows being the design used for placement of mast.
    Looks like a dual sail as you explained. Another diffrent take on the Aframe. I love it. And that frame looks really high I wounder what its length is.
    Great work well spotted. Thanks so much.
    And an update thanks to a kind user here I have contacted the designer of the Voyager to ask some questions and maybe buy a plan for his design as I love it. So I may end up with an Aframe after all.
    Now Ill have to get a move on and rigg the two 14ft cats I have to compare data with. Although I must say I am going to have to gerry rig an Aframe for one so the weight may be a little heaver then needed because I dont want to get it down to the water and have it break without getting to try the rig. Im going to do a test with an extended wishbone I made from an old windsurfer and on with no boom at all.

    Please keep us informed of any info you get about above boat.
     
  10. Spiv
    Joined: Jun 2007
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    Location: The Big Wide Blue Brother

    Spiv Ancient Mariner

    A Frame wing masts cat

    I met with the owner and had a look in and out of the boat.
    It is a Kelsall 33 extended to 36'.
    Yes, the coach roof is Marconi rig designed, but the owner went for the Kelsall designed A frame after he built the roof.

    Each rotating wingmasts weigh 40kg, the brace on top weighs 8kg, the rigging is Spectra and weighs 2kg. Total weight 90kg.
    The masts are 1.5m shorter than the single mast and he could have made them lighter if he'd used only carbon rather then glass with carbon reinforcement.
    So what he's ended up with is a lower centre of effort and really easy handling of the two smaller sails. No genoa.
    He did agree that she one sail blankets the other on a beam reach and that is the only drawback, shared by all bi-plane rigs.

    He hasn't sailed the boat much as he is busy with work (aren't most people in that predicament....), but we are going for a sail in the next couple of seeks and i will be able to tell you how she sail. He hasn't ever taken her out in more than 25~28kn, so never tried sailing with masts only (BTW, each mast is a 4.5 sqm sail).
     
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  11. Gus7119
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    Gus7119 Senior Member

    A frame Dacron 90KGS. WOW......

    Really intrested in the our come. 90kgs seems ridiculous. And mast sailing could be intresting. Maybe not in a force 10 or anything that could sort the boys from the men!
    Please grav lots of photos and keep us updated. Let him know hes got some very intrested people egar for some knowledge.
    So he built the masts himself out of glass with carbon reinforcement. Any chance you could get some more sneaky details of age old rig and how he found and choice designer.

    Cheers
    Gus
     
  12. UpOnStands
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    UpOnStands Senior Member

  13. pogo
    Joined: Mar 2010
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    Location: Germany Northsea

    pogo ingenious dilletante

  14. UpOnStands
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    UpOnStands Senior Member

    Spiv, the weeks are going to be too slow. Inquiring minds want to hear your experience, how well does it sail.

    Pogo: its interesting, has Chris White ever published hard claims for the additional flap?
    as in "correct flap setting increased boat speed from -- to --"
     

  15. pogo
    Joined: Mar 2010
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    Location: Germany Northsea

    pogo ingenious dilletante

    From Chris White's HP:
    "Why does the foil have an articulating trailing edge flap?
    Because a flap adds lots of power to the foil with very little additional weight and complication. Reaching and running the flap is set at a significant angle (approx 40 degrees) to the main foil which increases the overall camber of the foil and can nearly double its power. Sailing upwind only a small amount of flap angle is used but it helps create additional lift with very little drag.

    Is the MastFoil difficult to trim?
    No. The forces required to turn the foil are very low. The angle it should be trimmed to the apparent wind can be determined by watching the streaming action of normal tell tales. However, the nature of a rigid foil with a rounded leading edge is that it has a wide range of trimming angles that work, so trim is not particularly sensitive.

    What happens with the MastFoil when the boat is on the dock?
    Because the MastFoil can rotate freely (when the control line is released) the foils will automatically feather themselves into the wind, thus causing negligible drag and lift.

    What happens with the MastFoil rig offshore in a storm?
    Nothing, if that is what you want! The foil will feather into the wind on any point of sail. When feathered, the drag of the mast and rigging is reduced by about 90% over a conventional mast. In severe weather having the least windage possible will make handling the boat safer and easier.

    Is the mast rotating?
    No. The MastFoil mast is a very simple non-rotating mast. This avoids the numerous problems associated with rotating masts such as unfair halyard exit leads, corrupted masthead instruments and lights, inability to adequately tension the shrouds, etc."

    A- Mast
    from diagonal to horizontal Lift
    http://www.boatdesign.net/forums/multihulls/chris-white-atlantic-47-mastfoil-40670-4.html
    Chris white Experimentend in the 80s with a similar Concept, Named "tilting rigg"
    http://www.wingo.com/chriswhite/tiltrig.html
    i ' have a VHS-Video about his Planing 20' catamaran in Action.
    perhaps it is available on Youtube ?

    pogo
     
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