Small part-time job offer. Looking for someone, who could draw plans for ~5m sit on top kayak type

Discussion in 'Boat Design' started by xellz, Nov 22, 2017.

  1. xellz
    Joined: Jul 2017
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    Location: Japan

    xellz Junior Member

    Not sure if it's the right forum i'm posting in.

    I've posted idea about this boat before, now i have more or less clear idea about what i want. Since i'm not engineer i don't think i can draw something that won't break or won't be overly heavy. Or if it's possible at all.

    Material i would like to use russian birch plywood/highest exterior grade plywood, epoxy/fiberglass.

    Hull 5m long, 0.8m wide, displacement speeds. If performance or stability during drifting can be improved can go a bit longer or wider. Sealed hull, it's not uncommon that waves can go over and fill seat with water on my current Hobie kayak Revolution 13 (4.09m x 0.72m) or i return completely soaked. I want similar hull shape to this kayak, but open to recommendations if ease of build/speed/stability can be improved. I'm most concerned about strength calculations.

    For propulsion i want to use electric motor in the 0.6-1kW range, shaft, rudder.

    Here is biggest problem i'm facing now, i want to attach retractable wheels that could support full weight of boat, gear and person on it. (i guess around 200kg in total) I.e. when arrive to concrete ramp, move wheels in working position and pull myself up with rope or if it's too heavy, then use electric winch. Same for launching, get everything ready, sit down and lower myself into water, retract wheels and go. I'm thinking of attaching one stainless steel pole on the top of the nose and one behind center of gravity. I've added simple drawing of what i mean, front wheels rest on top when not in use. Red stainless steel pole, green is rubber/soft material attached to another pole that will rest on stem when wheels are in use. And i want to store the boat on those wheels. No long distances, only concrete and asphalt, at most i would have to drag the boat about 50m to home.

    If someone can draw plans for requirements above please send me a private message with rough price estimation. I would like to start building in January/February, so i won't have any problems finishing before summer.
     

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  2. kerosene
    Joined: Jul 2006
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    kerosene Senior Member

    Custom design is costly. Western experienced designer us going start from nearly $100/h and keeps going much higher (these are guestimates by me working in another field). Doing detailed plans takes time.

    I say:

    1.
    Use existing plans and modify them with commin sense/validate changes here.
    2.
    Forget the elaborate launching plan. If nobody else does it neither should you. Every decisuon that errs on the side of exotic will create unnecessary complication (potentially significant) to a challenging enough project.
    Launch with dolly as light as possible, walk it on a rope to dock and liad there. 200+kg point loads are not minor on a light weight boat.

    Plywood Boat Plans http://www.jemwatercraft.com/proddetail.php?prod=PB14-32
     
  3. TANSL
    Joined: Sep 2011
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    TANSL Senior Member

    It seems that you not only need to draw some plans but also perform the calculations of the project, that is, a complete basic project, naval architecture and engineering. Is it like that?
     
  4. kerosene
    Joined: Jul 2006
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    Location: finland

    kerosene Senior Member

  5. xellz
    Joined: Jul 2017
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    Location: Japan

    xellz Junior Member

    Yes, complete basic plans. Hull structure only with nothing on top. I'm not sure how high price can go and depends on offer decide if it's worth. Main reason for mounting retractable wheels is for quick and easy launch and retrieval from concrete slope. There is no floating platform where i could get off first and can't leave dolly near water too, since tide difference can be over 2m if i remember right. If i take dolly with me, like i do with my hobbie kayak, i will have to get off in water first to not damage hull and this i would like to avoid. I saw small boats and some dinghy with permanently attached retractable wheels, so thought it's not impossible. Not exactly pretty and takes extra space, but works. I don't mind extra weight, as long as it can carry one person with gear. At 5m should not be a problem.

    Will help if could make rough price estimate, how much this kind of work could cost. Might be way out of price range that still makes sense for this project.
     
  6. xellz
    Joined: Jul 2017
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    Location: Japan

    xellz Junior Member

    That's quite expensive start sure, especially not known how many hours it will take. I'm not quite ready to pay more than what i paid for 30ft catamaran plans, not custom made of course.

    It's not so elaborate and there are small boat and dinghy's with retractable wheels mounted, that's where i got this idea. It's just not exactly good looking, takes space and most importantly, not useful for most people. My weight estimate is for everything, ~50kg hull, ~50kg for batteries, motor, shaft, ~100kg human with gear, fish, ice
     
  7. xellz
    Joined: Jul 2017
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    Location: Japan

    xellz Junior Member

  8. TANSL
    Joined: Sep 2011
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    TANSL Senior Member

    Forget, then, geting help from a professional. Maybe someone can give you help selflessly but here, one of the main problems is that the designer is exposed to propose to you things that you do not like and enter a spiral test-error totally exhausting. You should define with absolute clarity what you want so as not to make that "help" more painful than it should be.
    Good luck
     
  9. xellz
    Joined: Jul 2017
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    Location: Japan

    xellz Junior Member

    More than 1000 usd certainly won't make sense here, but for this project general kayak hull is good enough. Like this one Plywood Boat Plans http://www.jemwatercraft.com/proddetail.php?prod=WF15-32 and many other fishing kayaks in similar size range Most important that it won't break when getting out on wheels and during storage on those wheels.

    I'll try to contact JEM Watercraft, since they have already sit-on-top wooden kayaks and perhaps one of their designs can handle what i'm trying to achieve. Or can make larger version without really high price.
     
  10. TANSL
    Joined: Sep 2011
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    TANSL Senior Member

    If you simply try to adapt an existing project to your needs, I have no problem in helping you, free of charge. Only the adaptation of the shapes, revision of the scantlings, if necessary, and the naval architecture calculations. It is essential to have an exact description of what you need and equipment on board.
    If you agree, send me a PM.
     
  11. portacruise
    Joined: Jun 2009
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    Location: USA

    portacruise Senior Member

    Have you discarded the idea of breathable waders, to keep from getting wet when you dismount for wheels? Every kayak design I've seen means getting wet to some degree, and in some cases, your feet will be marinating in water.

    Retracting/deploying wheels from a stationary seated position will likely be the hardest part. Myself would get a cheap used junker kayak and experiment to get the wheels concept down, before building the kayak I wanted.

    PC
     
  12. xellz
    Joined: Jul 2017
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    Location: Japan

    xellz Junior Member

    Perhaps was a bit naive about how much time it takes to design hull from scratch, since i didn't have any idea on custom design pricing i just guessed it would be several times of existing designs. Ready designs for kayaks/small boats are under 100$. Most likely will buy one of Jem Watercraft designed sit-on-top kayaks and strengthen structure for wheels, TANSL can go over design and recommend how to increase strength. Modifying size after all will be too much to ask.

    In summer certainly it's not a big deal, in winter however fairly unpleasant without wet suit. Hobie kayak is quite dry, splash proof cloth is enough. Even if it's troublesome i want to follow through this project. First of all it's really fun to make something unusual and second will be good for friend here, he's a farmer and growing premium japanese black beef cattle. During free time often going fishing, it takes time to prepare and launch kayak, can't leave on wheels near water or it will loose shape. Means need to remove everything, fishfinder, battery, wash pedal drive etc. Hobie pedal drive is quite efficient, but after day at farm still a bit difficult to go far. On wooden boat i could just make a watertight box with window for fishfinder, battery condition display and just mount it permanently to boat. Only need to pull out boat from water, give a quick rinse with freshwater, plug cable for charging. I want to use this boat too while i'm working on my catamaran, planning to start in summer and most likely will take over a year to finish.

    Front wheels are fairly simple and can use from sitting position, rear wheels can reach from seat and lock manually. I'll search for existing designs a bit more, no need to rush. Go over requirements again and go with most closest existing design.
     
  13. kerosene
    Joined: Jul 2006
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    kerosene Senior Member

    your plan sounds pretty good. Existing plans are a good base as they will explain how to build the boat, not just dimensions. As said the modifications you can sketch on paper and share here for feedback. Tansl hasoffered to help and many other will probably give good pointers too. Good luck with the project.
     
  14. rwatson
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    rwatson Senior Member


  15. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Why would you need TANSL to go over an established set of plans, to insure strength and stiffness? The retracting wheel assembly needn't be heavy or extravagant, as kayaks don't weigh much so loads are low. In fact, I've seen rigs like this that are designed to get stuffed into a hatch after you launched. In other words, don't over analyze this, a couple of rollers and a handle are all you need. Wheel it down, climb in, stow your gear and head off.
     
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