Modify Dragonfly 800 Mk II to fold amas

Discussion in 'Multihulls' started by 28N16W, Aug 6, 2015.

  1. 28N16W
    Joined: Sep 2009
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    Location: Tenerife

    28N16W Junior Member

    I have a chance to buy an old Dragonfly 800 Mk II. The yacht is in a fairly poor state, although the center hull is quite sound. Lots of neglected wood maintenance and it must have been years ago that the boat was cleaned.

    The worst of all are the akas and the joints to the amas. The akas are made from extruded aluminium mast sections and especially on the connection points of the stainless steel water stays the aluminum has all but gone.

    The ama/aka joints are glass fibre and 2 of them look cracked.

    Below this post I add some links to foto's that I took last sunday.

    It is obvious that if I am going to buy this boat I have my work cut out for me, especially on the amas and akas. The question I am asking myself is if I want to do this at all, and if yes, if I could take advantage of the fact that I need to replace anyway and invest some money in adding a folding mechanism to the Dragonfly (doing away with the aluminum akas and design and build new joints to amas and center hull)

    Is this a stupid idea? I am willing to invest in the boat because if it would be in good condition and folding it would come quite close to what I see as the ideal yacht for me.

    Also, I have a technical background and like designing and building things.

    All comments wellcome.

    Gert

    PS: Here are the links to the fotos:

    http://ecostar.es/Dragonfly/20150802_111438.jpg
    http://ecostar.es/Dragonfly/20150802_111442.jpg
    http://ecostar.es/Dragonfly/20150802_111520.jpg
    http://ecostar.es/Dragonfly/20150802_111536.jpg
    http://ecostar.es/Dragonfly/20150802_112122.jpg
    http://ecostar.es/Dragonfly/20150802_112149.jpg
    http://ecostar.es/Dragonfly/20150802_112209.jpg
    http://ecostar.es/Dragonfly/20150802_112213.jpg
    http://ecostar.es/Dragonfly/20150802_112219.jpg
    http://ecostar.es/Dragonfly/20150802_112229.jpg
    http://ecostar.es/Dragonfly/20150802_112756.jpg
     
  2. waynemarlow
    Joined: Nov 2006
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    Location: UK

    waynemarlow Senior Member

    The easiest to build with the least amount of cost and almost as good as the Farrier type, is the way the SeaCart 26 folds. If you only want to fold the boat in harbours ( one side ) or once its on the trailer then this method works well.

    If you plan on only limited folding in Marinas ( say you only want to go down to 3.5m to fit a berth ) then reduce the length of the upper arm, it leaves the Floats more vertical and you won't get that really ugly water mark along the side of the Ama which the Farrier type gets.

    The DragonFly method is great but come at a cost of weight and limited practicality whilst trailering as you still have to disassemble the floats to get them to fit width wise.

    Best of luck, there is a lot more work than what at first glance deems, to create a folding system, so take that into consideration of the price of the boat
     
  3. 28N16W
    Joined: Sep 2009
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    Location: Tenerife

    28N16W Junior Member

    Thanks waynemarlow,

    Useful info. My aim is to replace the existing akas which are in such a bad state and at the same time be able to reduce beam for berthing, and demount for trailering. I prefer a simpler system and especially one that avoids having to cut into the center hull to create the embedded pivot points.
    I took a look at some Seacart 26 images on google, but do I understand it right that it just has 1 arm? If it has 2 then what is the basic difference between the seacart and farrier systems?
    The dragonfly swing wing system is indeed the least attractive IMO.
     
  4. Corley
    Joined: Oct 2009
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    Location: Melbourne, Australia

    Corley epoxy coated

    Folding seems a complicated retrofit on what is a light and simple boat I agree that it makes the boat easier to trailer but perhaps not the best design feature to attempt to retrofit. It looks like it needs a lot of work perhaps best to simply fix it up and sail it in its stock form. It's easy to over capitalize a marginal boat like this.

    Just out of interest Kurt Hughes offers a design for upgraded foam/glass floats for this model with more volume and waterline length.

    http://multihullblog.com/2015/06/new-dragonfly-amas/
     
  5. 28N16W
    Joined: Sep 2009
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    Location: Tenerife

    28N16W Junior Member

    As far as I can tell the main hull is sound. And I think this is the value of the boat. The sails are also in surprisingly good shape. The main hull, according to my own judgement, just needs stripping down and a complete new paint job and replace all wood work. The interior seems fine too.

    The only doubt I have on the main hull is the state of the underwater surface. If you look here: http://ecostar.es/Dragonfly/20150802_112149.jpg, does anybody think this is osmosis? Or just old and probably badly done paintwork and anti-fouling?
    This seems like a very interesting option. The amas and akas are what need replacing and these are designed for the DF 800! I have already contacted Kurt on his blog for more info.
     
  6. Corley
    Joined: Oct 2009
    Posts: 3,740
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    Location: Melbourne, Australia

    Corley epoxy coated


  7. Manfred.pech
    Joined: Apr 2010
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    Location: EU

    Manfred.pech Senior Member

    From the pictures I think the boat is 28 years old or more. There seem to be some "amateurish/hazardous modifications" with the waterstays, the beams and the floats. The main hull looks as if there have been "accidents" which were cured with glass mat and putty -- not very professionally. Have you tested the strength of the laminate especially around the centerboard and other spots? Is it soft/weak ? Does it crackle/crinkle when you move around or when you press/push it ? Are there more hollow sections like the one in the cockpit ?
    The older Dragonflys (here 1987?) were not built to the same standards as nowadys. There have not been the highest quality standards with special e glass fiber glass composites and special resins. The hulls are built with standard mat and a bit roving here and there and as light as possible. No carbon or kevlar etc.. Customers reported that the main hull is flexible in a seaway. Old boats like this one have been moved may be a hundred thousends (?) of cycles. And many of the Dragonflys have been raced extensively. Ergo: Please, test the bottoms/tops and sides of all three hulls carefully. And of course your photos show severe blistering.

    The sails seem to be o.k.. Prima! But what about all the stainless steel? Did you test it ? Stainless steel is prone to "interkristalline Korrosion" (intergranular corrosion?) and "elektrolytischer Lochfraß" (electrolytic pitting?) and the whole trimaran can collapse without warning. Please look at all the rigging parts!
    Dragonflys here were the racing cars of the water in their days and they had and have to be revisited year for year and a lot of parts have to be exchanged from time to time as for instance the J - hooks and their slots in the beams.
    Some of the owners gave their boats into the factory every winter to get weak parts exchaged or repaired. That seems to me the best way if the boats are raced.
    One last point. I am not sure about this trimaran. One of your photos shows the plate in the cockpit indicating the "Quorning Dragonfly". But I have not seen a photo of the whole boat. Are you sure that it is not a clone???
    I know at least of two similar boats which are said to be clones, the "Firefly", a product of "Running Tide Yachts, Ltd." and the Elan 7,7. Both have enlarged cockpits by moving the after beam to the end of the cockpit and the floats. But are there other clones?

    Please do not worry about my comments. Click them away if they are not useful for you. With all my boats I had the same experience when I bought them new or used: I didn´t see the reality but I saw what could be of them when I would be ready with all the improvements. Thus I lost a lot of time for sailing. I hope you will make it better.

    Dragonfly 800 Mk II

    [​IMG]

    [​IMG]
     
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