So much for the "Nay Sayers" (Powered O'Day Javelin 14.9 mph)

Discussion in 'Boat Design' started by fredrosse, Oct 31, 2013.

  1. fredrosse
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    fredrosse USACE Steam

    A while ago I was asking about pushing a converted O'Day JAVELIN hull relatively fast, on the forum thread "Powered O'Day Javelin". The JAVELIN is a small (14 ft) centerboard planning sailboat, mine had been converted to electric drive: fiberglassed a new shaft tube where centerboard was, 14 x 17 three blade propeller, plus two bilge keels for stability.
    It worked fine for years as a slow quiet cruiser, but I wanted to push it fast, with 10 - 15 horsepower.

    Describing the boat, and asking for info on this forum, the replies were typically from senior members, and very negative.

    Some examples:

    "first time you put the boat in the water it is going to sink."

    "I would be absolutely shocked if you can get up on a plane"

    "say about 7 - 8 MPH. If you try to push her much faster then this, she'll be come progressively more unstable, sticking her nose higher in the air, the faster you go"

    "She'll start rolling around and eventually get so unstable that it'll flip, swap ends or do some other undesirable thing underway,"

    "When she's standing on her tail with 3/4's of the boat flying out of the water, how much do you think those runners (bilge keels) are going to be engaged?

    "Maybe two Javelin's glued at the transom?"

    Those comments are from the "Nay Sayers".

    So, the proof is in the pudding, I put a 12 horsepower engine in the JAVELIN and went out for a test drive. She made 14.9 MPH as indicated by the GPS (speed grapher) several times on the lake, and did not misbehave like everyone said. I have to wonder why certain persons were so sure it wouldn't work?
     

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  2. FMS
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    FMS Senior Member

    Congratulations Fred.
    How much was the weight of your boat in the video?
     
  3. Squidly-Diddly
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    Squidly-Diddly Senior Member

    Thats great, how about a rough MPG estimate from what the motor burns vs speeds seen?

    I'd been batting around an idea for a 'universal sport utility boat' based on a planing sailing dingy, but that would do about 15-20 with an outboard, but which could also sail or row decently, and be about 20' and able to do a wide range of duties with a little easy reuse of dagger boards for benches, etc.

    I too got mostly neg feedback about using a planing sail hull to motor with.


    How does that thing do at "max displacement speed" under power, especially MPG wise?
     
  4. tom28571
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    tom28571 Senior Member

    Fred may be having some fun at the perceived distress of "nay sayers" . On the other hand a decently designed power runabout of the same general dimensions and weight would probably make double the speed he got with the Javelin. It works but is nothing to rave about. I had no comment at all about the Javelin so have no dog in this fight.
     
  5. Saqa
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    Saqa Senior Member

    hmmmm I reckon it is something to rave about when it does what you wanted and performs contrary to the mass opinion :D <removed>
     
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  6. Mr Efficiency
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    Mr Efficiency Senior Member

    Yep, they said Einstein was wrong, then they said fredrosse was wrong, can't dem wiseacres get anything right ?
     
  7. moTthediesel
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    moTthediesel Junior Member

    I say Fred deserves some congratulations, and I think he is quite right in crowing a bit. To me, 15mph from a 14' boat with a 12hp inboard is a pretty good result -- it's unquestionably on plane, and moving at about 100% over one "nay-sayers" estimate.

    It does seem to be dragging it's tail a bit -- but with the rising buttocks in the Javelin's run, that is to be expected (and unavoidable). The high spray cutting off the bow could be a little wet I suppose, but I love the look of it -- very vintage powerboat! Reminds me of watching "Don Winslow of the Coast Guard" as a kid.

    One question -- what kind of engine is it?

    Tom
     
  8. fredrosse
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    fredrosse USACE Steam

    I think the major reason the boat does so well in speed is the relatively large and low speed propeller. The bilge keels keep it stable, and perhaps they might be extended to reduce spray, but I am no expert here.

    The engine is an inexpensive ($360) Harbor Freight 420cc single cylinder engine, driving thru a 3.125 reduction, with a 14 x 17 prop. This engine was just put in to test out the setup, and this weekend I will try to see how the boat does with about 300 pounds more weight up front, as that will match the end result I am thinking of with the intended propulsion unit.

    At about 9-10 MPH the boat is much more comfortable, and that will do very well for most of my intended cruising, but going 14-15 is a nice option.
     
  9. moTthediesel
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    moTthediesel Junior Member

    Of course I'm curious what your 300# heavier engine package will be, -- especially given your avatar...

    Where was that video clip taken, upper Delaware River maybe?
     
  10. fredrosse
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    fredrosse USACE Steam

    FMS," How much was the weight of your boat in the video?"
    Do not know, but will weigh it very soon in the boat building workshop where I can lift I off the trailer and get a fairly accurate weight. I would Guess around 900 pounds, more or less.

    Squidly-Diddly, "how about a rough MPG estimate from what the motor burns vs speeds seen?
    The typical engine of that sort uses about 1 pound of fuel per horsepower-hour, so twelve pounds per hour, about 2 US Gallons per hour, so something in the vicinity of 7.5 MPG at 15 MPH top speed.

    Tom28571, "a decently designed power runabout of the same general dimensions and weight would probably make double the speed he got with the Javelin."
    Is that actually true that a typical similar size power runabout with a 12 horsepower engine would make 30 MPH? Where could I find this type of hull? I was just trying things with the JAVELIN hull because I have it sitting on a trailer in my back yard, and had not used it for a couple of years. No real expense to try things out, and I like the looks of the JAVELIN hull.

    MoTthediesel, "Of course I'm curious what your 300# heavier engine package will be, -- especially given your avatar"
    I am planning a high performance steam plant, not unlike the steam plants used in the 100+ MPH steam hydroplanes the Brits are somewhat fond of. These small tethered model boats run at 10,000-20,000 RPM, but I plan something much more civilized at around 1000 RPM, with much less fuss and noise. Steam power has been my passion, and my day job, for almost 50 years.

    "Where was that video clip taken, upper Delaware River maybe?"
    Very close, I have cruised the Delaware and Schuylkill rivers with the JAVELIN (in electric form) as well as the sidewheel steamboat, but the posted video is from
    Lake Nockamixon, a few miles west of the Delaware river in PA.
     
  11. fredrosse
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    fredrosse USACE Steam

    What got me started in this direction, The steam launch "Oberon" which uses a 15 horsepower LIFU (Liquid Fuel Engineering Co.) steam plant of about 1906 vintage, this boat has been clocked at 17 MPH.

    Look at some impressive steamer performance on youtube, go right to the middle of this four minute video: "Steam Launches Oberon and Ariette running at speed on Lake Windermere"

     
  12. tom28571
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    tom28571 Senior Member

    My post had no intent to disparage what you are attempting to do with your Javelin. A utility runabout that I had in the 1950's could do almost 30mph with a stock 10 hp outboard.

    Racing boats, utility types not hydroplanes, could do twice that or four times your speed. Not surprising at all since the key to these speeds is light weight, a suitable hull bottom and balance, none of which the Javelin in the video possesses.

    The Javelin in the video is making quite a bit of waves with the stern being sunk down by weight and the aft hull shape which is not good for high speed. Compromises must be made for a sailboat that runs at displacement speed most of the time and rarely planes. Looks jaunty but is not fast. Pushing the bow down by adding weight forward may (or may not) increase speed but is very likely to make the boat wetter on the occupants.

    I admire your efforts and your results and hope the steam power works out.

    Some of the boats I was referring to:
    http://www.boatracingr11.com/Sorensen_boats/sorensen_classic_b.htm
     
  13. moTthediesel
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    moTthediesel Junior Member

    Sounds like a very interesting project. I'd like to hear more about the steam plant. Maybe a uniflow with a flash boiler? LP fired?

    Tom
     
  14. messabout
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    messabout Senior Member

    Kudos to the OP. He has proven that given enough power, a brick bat will plane. Not to say that the Javelin is a brick bat but to say that its primary operational charecteristic is not that of a planing hull.

    I happened to have an old Thistle hull at one time. I also happened to have a near new Johnson 9.9 (a 15 in sheeps clothing) The Thistle would plane, kinda, sorta, at about 13 knots. It would also throw a wake about the size of a naval destroyers. The Thistle and the Johnson were very happy at about 5 to 6 knots of Johnson idle speed. It was quiet, almost wakeless and a pleasure to use.

    In the grand scheme of things, nothing is impossible. Impractical or improbalbe maybe, but not impossible. Those curmudgeonly old senior members were not so much nay sayers, but more certainly, practical and experienced individuals who knew about sensible limitations.
     
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  15. fredrosse
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    fredrosse USACE Steam

    FMS," How much was the weight of your boat in the video?"

    Put the Javilin on the load cells, total weight is 811 pounds, so with the driver (me) at about 175, the total weight in the video is 986 pounds.

    messabout, "Those curmudgeonly old senior members were not so much nay sayers, but more certainly, practical and experienced individuals who knew about sensible limitations."

    The issue here was that a displacement speed type of boat guy (me) was merely asking what might be expected with the Javelin and 10 to 15 horsepower. The answers I got painted a picture far far worse than the results (look at the replies!), and I now wonder why these answers were evidently so far off? Yes, the Javelin is certainly not anything of a proper planing powerboat, even I knew that from the very start.
     
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