CNC Plans not Included

Discussion in 'Multihulls' started by jorgepease, Sep 19, 2016.

  1. jorgepease
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    jorgepease Senior Member

    Yeah, I agree on that, why tempt somebody.

    This is the video I mentioned with a snippet of infusion at 1:10 - https://youtu.be/oLSdZNRXnvk

    Not sure what those ribs are (BulkHead Landings?). If so why don't they extend further up.
     
  2. rob denney
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    rob denney Senior Member

    It is more work, but not difficult to include a round or V'ed forefoot with a box mould, either pre or post infusion. However, my preferred solution is a rockeries hull, which is more pitch resistant, potentially faster and easier to build. Not as easy to tack (although John Hitch's Wired apparently had no trouble), but that is not a problem with a harryproa. If you did put a shaped bow on it, I would still recommend a flat floor further aft.

    Jorge,

    Pretty sure those are partial ring frames, not bulkhead landings.
     
  3. jorgepease
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    jorgepease Senior Member

    Yeah probably so but I think that concept would work well. It might require a trim on one side to make look right but I think it's the easiest way because you have a little play.

    I was playing with Graingers Flying Fish 50, assuming an open cockpit, I stretched the bow 5' and the stern 5' without touching anything else. That shouldn't add too much cost, looks awesome and probably increases the amount of stuff you can carry without losing performance.

    Here is a look at them together
    [​IMG]
     
  4. jorgepease
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    jorgepease Senior Member

    Been contemplating retractable elec. sail drives or just elec. outboards connected to a portabracket (24" movement). I inquired about shipmotiongroup retractable drives. They are nice but wow!!

    I don't think that counts the Torqeedo's, which means just one retractable unit costs more than the entire torqeedo system - 2 motors with batteries and controls .. lol who would pay that??
     
  5. waikikin
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    waikikin Senior Member

    That is wow, must be a typo on the zero because I want the whole boat or a large percentage for 350K euro..
    Jeff
     
  6. jorgepease
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    jorgepease Senior Member

    yeah, 35K might be doable, I can't see them getting too much business at 350K. Schionning posted this guide on Facebook, right up there with the material cost of a 15 meter cat

    [​IMG]
     
  7. jorgepease
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    jorgepease Senior Member

    A cat with daggerboards can have as little as 2' of draft, I don't want to ruin that by hanging motors off the bottom.

    Since I intend to use electric, I just had an idea, why not mount them on the sides of the hulls like this mini sub.

    EDIT: Ok I just heard back from Torqeedo and they believe it would be okay as long as hull is reinforced in that area. I think I just found my solution!!

    [​IMG]
     
  8. sailhawaii
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    sailhawaii Junior Member

    I think mounted on the side, you will have issues with the prop coming out of the water, unless mounted mid ship where you could get them deeper. My thinking was to mount them on a kick up box on the last transom step that also had the rudder attached.

    BTW here is a thread to the catamaran plan I'm working on:
    http://www.boatdesign.net/forums/boat-design/45-cruising-catamaran-project-56566.html

    My current plan is to release it Creative Commons (meaning free). I will have all the CNC cut files for the panels as that is how I plan to build it.

    I'm not very far on it and currently making lots of changes based on feedback I've received.

    -Bryan
     
  9. jorgepease
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    jorgepease Senior Member

    I saw your thread, I like the look but I know very little about what makes a good Catamaran, keep bridgedeck high, nice big tramp up front, weight to centers, etc etc... just what I read but it's a great project. I downloaded Rhino and have been fiddling with it but think it might be overkill just to edit cut files.

    Yes on the motors being mounted amidships, boat has a draft of about 2' so plenty of water. The other option would be as you say, on the stern with maybe a portabracket to raise and lower but I'm a bit worried about theft in that case.
     
  10. jorgepease
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    jorgepease Senior Member

  11. redreuben
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    redreuben redreuben

  12. jorgepease
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    jorgepease Senior Member

    Also, it seems the problem of having the prop aft and popping out of water in seas, would remain.
     
  13. redreuben
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    redreuben redreuben

    I guess that would depend on how far down the rudder you installed it ?

    A big cat is going to have a much deeper high aspect rudder than the little mono.

    It may even fit in the junction of a T foil rudder ?
     
  14. redreuben
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    redreuben redreuben

    Uh Oh I said the "F" word !
     

  15. jorgepease
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    jorgepease Senior Member

    There might be one drawback - The idea of keeping the prop up above bottom of boat is so I can motor in the shallows. In these cases, the rudder would be up.
     
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