Swath Boat building Plans

Discussion in 'Boat Design' started by blackdaisies, Sep 1, 2008.

  1. Qhiron
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    Qhiron Junior Member

    here's one swath that could not, but it is fun to look at--
    talk about heeling, bow high

    http://www.boatdesign.net/gallery/showphoto.php/photo/7669

    Yipster: you had a fun sketch trike swath runabout.
    e l o n g a t e
    it and give the prop clear water rear. less is more, keep it simple. See, sim ideas abound broadly....
     
  2. Qhiron
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    Qhiron Junior Member

    3 sketches as requested

    Graphics you wanted. Here some rough ideas that won't work as shown, masalai.
    The concepts are simple.
    1. Seaskimmer is a 2 occ. hybrid diesel electric, @3t, with elec. propulsion waterjets in each outrigger. This allows for min. cross section, greater length, stability, and more dynamic variables. These subsurface torp tubes can be ballasted either with seawater, or buoyed by air to adjust loading and dynamic attitudes. If extensions are hinged to main vessel trunk (hydraulics) the swath can adapt to sea conditions instantly as req'd.
    A cG diesel/gen hybrid engine provides electricity to pods
    2.The swath trimaran is considered one of my early attempts at rec. cats. Again, BF, trim for heeling, toeing and list would be adjusted according to buoyancy of each pontoon. The overall hull shape above surface can be of almost any configuration. In this sketch I'm working with a flat ellipsoidal form. This prelim has changed, radically.
    Note the bi level, rigid sails, -wings- considered fore, with a ketch style single mizzen mast near the stern. With rigid sail planes the angle of attack and 'dirty air' considerations are substantial. Like a biplane, lift -or in our case moment- can be augmented (venturi-effect) from one airfoil over the other. The advantage is cross-bracing the masts to eachother, since more than a specific interior angle (of attack of 33º) is unlikely... I hope!~

    3. The huge 70m quad-sail swath cat started with this sketch. Cross bracing four mastheads to each other with equally huge, rigid airfoils is circumspect, OK, but again BF, my point is the submerged pontoons can each be dynamically adjusted under varying load conditions. Mast structure to pontoon arm cantilevers are cross-braced, in more recent design evolutions. Each pontoon can be individually ballast-controlled, with sea water or buoyed by pressurized air.
    The second attitude control is applying hydrodynamic fins- controlling lift/submergence, while under motion (yes, increasing drag).
    And finally, with each hydraulic "arm" hinged as to pitch control, (+/-5º in either vert. direction) both static and dynamic attitude/height controls are calc'd relative to the main hull. Result: The ride 'height' can be adjusted according to wave amplitude under sail, or for ease of access/egress.
    The really nice features of this layout become evident in plan view, with the diagonal cross-braced steel trusses spanning through cockpit and habitable areas. Some really wild plan views.
    This design has the most spectacular application potential -as a seafaring vessel, esp. in plan view. It keeps me up at night with the variance of certain design parameters. Drag's most critical factor is all about direct frontal area submerged. What am I pushing through the water and how does this relate to the main hull attitude? Recent reports on laminar flow hydrodynamic wings suggest 1:1:48+ (w:h:l) as good pontoon volume ratios.

    Under high wind conditions with max sail foil exposure, leeward side pontoons are air bouyed, adding lift to the 'loaded' submergence depth, while windward side will have water ballast to keep pitch-neutral. Hence my comment, BF, that heeling can also be controlled fore to aft by such corrections.
    One other control consideration is to add horizontal rails (that attach to the outrigger arms) to the torpedo shape. This will alter bouyancy/ ballast fore/aft to each individual arm while under dynamic loading.

    While simple in concept, obviously this becomes rather daunting tasks in real design and construction applications. THAT's WHY GUYS I need some proposed overall dims..... However, the larger the dimensional considerations, to a point of structural absurdity- the better inertia and mass controls can become, even with applied dampening factors, yet t.b.d.

    For now, these old crude sketches defined my original concepts about swath potential. Yes, huge obstacles certainly are presented, but within the existing considerations of what is possible- with current technology? You tell me. If we can make an F117 Nighthawk fly, as aerodynamic as a brick, then modest computer-controlled pontoon modulation for the Seaskimmer is realistic.

    Slow, heck no. High drag, ahem, yes. Been on one of those 300HP Yamaha Seadoo racers recently? One single waterjet propulsion to 40kts.. Apply this to four pontoons, creatively, and you'll get one helluva stable platform at high speed, infinitely variable as to littoral waters or open ocean. I'll get in that. How about you?
     

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  3. yipster
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    yipster designer

    how about a mind controlled swath that senses its pilots emotions and can react in bio feedback mind control technology? do you really want water jets, which are btw above the waterline drives, but heck, they can be variable height adjusted right? how about a F1 offshore, at speed that's about the ultimate fuel swallowing small waterplane area twin hull. as said i like sails too, how about computer controlled foils for stability? think the legs are better off small at the top? seriously, i like sails, speed and the swath concept and even build 3 waterbike swath legs, bought and sold a small short shaft, need expensive extra long outboard but started hesitating putting out another grand for the tubing in my trike swath design. i made lifting body pods with aerelons witch later i realized most probably need computer control. Will Allison mentioned avoiding wave resistance pods take a certain depth etc.

    better build and play with a scale model first to get better insight in the concept, than read, study and ask around further before trying to sell us the otherwise nice sketches and letterhead. under an old tread named swat i once started Tom Speer gave an exellent description of the concept worth reading. i still like the idea of a hybrid but yesterday my sweet old suzuki got stolen without me having a theft insurance, ok new suzuki, mean second hand, coming up but hey, why not a boat thats roadworthy as well? take it easy on the building plans ;)
     
  4. BMcF
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    BMcF Senior Member

    Funny you mentioned waterjet propulsion for a SWATH..I remember one we were working on many years ago that had the slickest submerged jet propulsion built in to the 'pods' that I ever laid eyes on. Russian design... Practically 360-degree radial peripheral intake to the jet impeller...clamshell reversing 'buckets ' on the exit nozzles..just plain cool, it was.
     
  5. Ad Hoc
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    Ad Hoc Naval Architect

    QHIRON
    "...Ad hoc I agree weight is critical, but in what application?.."

    In all applications.!!
     
  6. Qhiron
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    Qhiron Junior Member

    jet propulsion vs sail

    This is best underwater, right Yip? You guys are mind control here. So much negativism I could pee on a fiure.
    BF, any links to that Russian thing?

    AdHoc I agree, but with sailing, where stability and consistency of inertia become prime, not speed, underwater mass is obviously preferable, right?
    Subject to heeling comments, I'd like to see torpedos as long and as narrow as possible for max. stability, but then this affects tacking, turning, manoeuvering...
    Yes, got to balance upper load to lower volume for neutral buoyancy, with the enabling volume changes, ballast/water/air tanks and mechanicals.
    The longer and more slender, I assume, reduces overall cross frontal area, maxQ, with better displacement LOADING (length/girth) and greater stability.
    Consider also that hydrodynamically adjusting buoyancy of each 'leg' on horiz. rails on each side of each pontoon, slides cG fore/aft according to dead load, load under motion, and moment arm to sail conditions.
    The smaller my cross area underwater, the stronger the cantilever arm, the denser and more structural each pontoon must become. Don't see too many disadvantages of pontoon weight, (yes, mass increase) since sail speed is not the critical design determinant, but stability and lack of heel/toe, and pitch.
    It is my belief -from conversations with builders- that these vessels become the natural evolution of luxury recreational yachts, very soon for the above reasons. Our clients don't necessarily get somewhere fast and uncomfortable, but rather with great stability and suitable speed.
    Am I missing something, BF?
    Who has a custom swath in Marina Del Rey I can get a ride on? Oxnard?
    Clamshell buckets jets,

    Propulsion concepts: Instead of a simple ducted propeller, (as in waverunners) how about geared, triple impellers? Broad diam. front fan for slow speeds, rotate to neutral at higher water speeds, second impeller smaller diam., greater critical angle.
    Third and final fan very small blades, extremely high pitch adjustment for nothing but highest propulsion -and smallest diameter tube. Greatest exit speed.
    Love the idea of 360º inlet...
    Sort of like a air turbine impellers adding compression factors at each stage. Since we're in water, no compression change differentials, just adjustable blade angles of attack. Middle fan is always under load, front and rear adjust according to speed...
     
  7. Ad Hoc
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    Ad Hoc Naval Architect

    Qhiron

    So many "what if's"...you really need to sit down and draw up a proposal and do a basic design. This will answer about 80% of your questions immediately, and almost all will be not possible, with the goal which you wish to achieve.
     
  8. BMcF
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    BMcF Senior Member

    To my knowledge the only SWATH yachts were both built by Swath Ocean Systems, formerly of Chula Viasta, CA. The first was 60' and the second 90', both named 'Chubasco' if I recall correctly. I believe that both are now owned by universities in California, donated and used as marine biology research platforms.

    Abeking and Rasmussen (Germany) is (or was) working on the design of an expedition SWATH yacht..but I have no idea where that project stands.

    George Petrie came out with the design of a small SWATH 'green' yacht too..with hybrid solar/diesel-electric propulsion. Not sure where that project stands either.

    The Russian waterjet propelled SWATH was never completed. The unique propulsion equipment is probably no longer even available..as is the case with very many of the novel Russian marine designs and, particularly, the related equipment. Much of that 'cool stuff' was military-derviative and only appeared briefly in the commercial realm before the companies that produced it went Tango Uniform.

    All of my discussion of SWATH vessels of course only pertaining to powered propeller propulsion...there is no other kind. Yet...:p
     
  9. yipster
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    yipster designer

    http://www.cruisecompany.net/radisson/radisson diamond.htm is swath but a cruise altho interesting is to expensive for me
    got my "new" car ok, but my 360 around negativism is still to be shaken off, what a world, every 15 minutes here and 30 second usa
    a car gets stolen and 90% is never seen again so wise guy's probably have allrisk insurance
    btw BMcF, any chance of a small drawing or explaning how that russion 360 degree swath jet worked?
     
  10. BMcF
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    BMcF Senior Member

    The drawings were provided to us as all paper format only and I no longer have them. As far as the concept, it was very simple..just imagine an aircraft turbine built in to the tail 'cone' of a SWATH hull. Radial inlet turned through impeller stage to axial exit (jet) flow. I wuld not be the least surprised to learn that the jet design was pinched from their submarine design bits. I saw a lot of that kind of cross-pollination in my working with various Russian designs over the years. Hydrofoil ferry vessels with their flight control electronics, sensors and actuation kit straight from submarine bow planes, for example.
     
  11. BMcF
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    BMcF Senior Member


    Interesting. That would be more correctly termed a 'lifting body' design than a SWATH. Lifting body technology is rather new on the scene but we could see more of it in future..although certainly not with sail propulsion.:D

    Similar in some respects to the HYSWAS concept, lifting body vessels rely on a combination of bouyant and dynamic lift to achieve the desired running height. They differ from the HYSWAS in that most of the dynamic lift is produced by the underwater body itself and not all from appendages attached to the underwater portion of the hull as was the case with the HYSWAS.
     
  12. kach22i
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    kach22i Architect

  13. BMcF
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    BMcF Senior Member

    ah yes.. one of, if not the most preeminent SWATH designers in the world. Dr. Don would get a real chuckle out of the idea of trying to build a SWATH with sails..:D

    That's our company web site linked from his web page..Island Egineering. But I don't know him...:p :cool:
     
  14. kach22i
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    kach22i Architect

    Picture of the hovercraft he used in that link, a craft you worked on?
     

  15. BMcF
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    BMcF Senior Member

    Yep. Belonged to us, in fact. Slingsby SH-2. Long gone now..up in The Canadian north somewhere serving as a taxi on frozen lake beds to some guy's winter cottage. One of many test craft that we have had ...


    That hovercraft in particular was fun but..required about 100 maintenance and repair hours for every hour of flight time.:rolleyes: Sorry Kach..:D
     
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