A small tri project

Discussion in 'Multihulls' started by Lurch723, Sep 25, 2017.

  1. Cholsson
    Joined: Aug 2015
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    Location: Gothenburg

    Cholsson Junior Member

    You can see my upwind-speed in my video below from last year (Before I started to rebuild the beams)

    And here, in no wind condision


    I rebuilt it because my beams where very sloppy and not stiff at all. Changed to twice diameter in carbon in the front..

    Yes, fun to see your approach. Your long centre hull looks amzingly fast!
    :)
     
  2. Lurch723
    Joined: Aug 2012
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    Location: Devon UK

    Lurch723 Junior Member

    Yeh it looks like in your first video you could do with more rig tension to keep the power in the sails.
    I liked the part where you decide the yacht is pointing too high and you duck behind it then your boat speed rapidly increases.
    Beam diameters are interesting, a lot of weight was added to my design by using the tube diameters I ordered; but it does have glass woven into it so has a failure mode. Increasing diameter has such a positive effect strucurally speaking because you can drop wall thickness substantially.

    I have yet to sail my boat in a good breeze so for now all I know is that it is easily driven and produces no spray and no bow wave to speak of, but it's designed to be powered up in 8-10 knots and so far I've only tried it in 5 knots of wind.
     
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  3. Lurch723
    Joined: Aug 2012
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    Location: Devon UK

    Lurch723 Junior Member

    More modifications on the original design, I’ve gone down to one tiller extension from 2 like on a skiff and moved the sheeting point forward on the boom. I’ve pretty much finished my front lifting foil and just need to fit a vernier adjuster to it and some tip winglets to reduce tip losses. I’m quite excited about the lifting foil as it means I can dial in lift from the rudder foil and balance it all on the front foil which is adjustable from -2 to +8 degrees AOI.

    From the last test sail I should be able to drive the boat much harder off wind and across the wind, accelerating instead of balking as a gust hits. What is also great about this test platform idea is the full flight surface piercing foil mounts in the same way as the foil I’ve just built, so I can change over foils in minutes.
     

    Attached Files:

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  4. Doug Lord
    Joined: May 2009
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    Location: Cocoa, Florida

    Doug Lord Flight Ready

    What are you using for altitude control? Good luck!
     
  5. Lurch723
    Joined: Aug 2012
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    Location: Devon UK

    Lurch723 Junior Member

    I can use a general setting on the main foil using vernier holes and fast pins and vary the altitude on the rudder by adopting a bow down or up attitude, but don’t get too carried away with the front foil it’s there for positive lift not for full foiling. I’m testing stuff Doug and having fun, I can understand a great deal by using this method. The next foil I’m going to make is full flight surface piercing but I probably won’t get a chance to try it myself because I want to sell her. I have some big work commitments that mean I can’t afford the time and energy to keep playing. So if anyone wants her she’s up for sale.
     
  6. Cholsson
    Joined: Aug 2015
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    Cholsson Junior Member

    Exciting! Looking forward to see your test-sailing :) I think I have got great upwind speed now with my boat, but need a code0 or similar furlable gennaker like the Weta to go fast downwind.

    Video from Wednesdays race
     
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  7. Lurch723
    Joined: Aug 2012
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    Location: Devon UK

    Lurch723 Junior Member

    Yes Cholsson you are so right, I thought my Hurricane was quick offwind but our tri’s develop so much more apparent wind; a cats kite is too full and the tornado kite proved a code Zero is the way forward. As soon as mine went up it was fully sheeted and we had to bear right off to almost a run to keep it from collapsing.

    I think your upwind speed is impressive, I don’t have a datalogger or GoPro to record stuff with , and I really enjoyed watching your speed which was very consistent I have to say - no big peeks and no big holes in the performance of your tri.

    There are a couple of observations I would make with regards the rig Cholsson, it looks like the jib depowers a lot when pressure increases, the forestay falls away and your slot opens up. Off wind the main looks like the leech is very twisted and probably loosing lift.
    But I also think you could have been trapezing a bit upwind as the leeward hull was pushing hard at times. So maybe getting more rig tension and rig control would improve boatspeed a little? What do you think about your rig? Does it feel a little “soft”?
     
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  8. Doug Lord
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    Location: Cocoa, Florida

    Doug Lord Flight Ready

    Great video -thanks! Sometime I'd like to know how you control the camera angle.......
     
  9. Cholsson
    Joined: Aug 2015
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    Location: Gothenburg

    Cholsson Junior Member

    Lurch723, thanks for all kind words!! Not everyone is that kind to my home built tri. thanks!
    About the observation, you are totally right! Actually I tried to make more tension to the forestay before the race but had no time. (Cut that part in the video)
    The forstay wire does not reach all the way, missing 3 feet (line the rest), and it was little sloppy. Will try harder next time.
    About trapezing You are right, I'm not allowed to do during "race" stated in my handicap-rule. I will try that later this fall when its not race. Think that could give some knot more upwind.
    I will talk to some sail-maker and see if I can order a Code0 this week.

    And Doug.. about the the camera angle... I may reveal the secret how its done later on ;)
     
  10. Doug Lord
    Joined: May 2009
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    Location: Cocoa, Florida

    Doug Lord Flight Ready

    ====================
    It would be much appreciated-it's a very cool system!
     
  11. Vantage475T
    Joined: Aug 2016
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    Location: Lymington,UK

    Vantage475T Vantage475T

    Lurch, have you completely stopped development on your project now? Are you still looking at selling it?

    I'd be interested in a chat with you about it and I'm not too far from you as I'm based in Lymington.
     

  12. Lurch723
    Joined: Aug 2012
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    Location: Devon UK

    Lurch723 Junior Member

    Hi Vantage,

    Yes I’m still developing it but no I don’t have any more time to put into the project sadly.
    After the last sail it showed some serious pace and capability, it was everything I wanted it to be, so I took the lessons learned and have changed a number of things like going down to 1 tiller from 2, moving the sheeting position forward, and building the front foil which I am painting in the next few weeks.

    But realistically I cannot put any more time and effort in as I’m running a new business which is taking all of my energy and finance. So I was going to put it up for sale but only for a fraction of the investment , perhaps £3700 - I ploughed in £13000+. It’s got a full road and launching trolly combi from Admiral trailers, foils from Synegy worth £3000 and the rig which is where the development needs to go.

    Because it’s so damn quick the Tornado kite is too full and only good for running, it’s that fast you can go downwind fully sheeted in on 2 sails and is very very balanced and controllable. It needs a code zero fitting which Rowsell sails said they would do for £800. The bad points are few and basically it’s a pain in the neck getting the main up and down, Simon Hiscocks provided me with them from Weymouth and I was contemplating on getting him to look at them to see if he could improve matters.

    Anyway if you want to take her on and move her to the next level then please call me or email me and we can talk. I would be delighted if it went to someone who can appreciate just how unique and mind bendingly quick it is.
     
    Last edited: Jan 6, 2019
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