Proafile v5.0 | Updated: Jul 28, 2010

Portfolio Proas

Rozinante II

Posted by on 01/10 at 05:41 PM
A considerable amount of credit/blame for my love of small boats goes to L. Francis Herreshoff and his book 'The Compleat Cruiser'. I fell in love with his ideas about a simple yet refined cruising lifestyle, epitomized by Mr. Weldon and his whaleboat type ketch - Rozinante. Rozinante is beautiful, fast, seaworthy and handy, and I was musing recently about how a proa version of Rozinante might work out.

Rozinante Il is a mono-proa - a bilaterally asymmetric monohull. Her dimensions, style and intent are all within the ballpark of the original. She's the Rozinante from the alternative proa-centered universe.



LOA: 28' | LWL: 25' | BOA: 6'-10" | Draft: 2'-10" | SA: 285 sq. ft.

She's a lugsail schooner, which gives us a well-balanced rig that is easily handled, reefed and shunted, and the character is in keeping with the small gaffs of the original ketch. The cockpit is 8' long and deep enough for comfortable seating, yet the floor is above the waterline which allows it to be self bailing (unlike the original). Also unlike the original, Rozy II does not have a weighted keel and her draft is 8" less, though the keel is still sharp and deep for good windward ability. Rozy II's ballast is in the form of a water ballast tank to windward, beneath the cockpit seat.



Rozinante II's most startling feature is the pronounced hull asymmetry. It looks daft, but there's good reason for it. A traditional monohull's waterplane becomes more asymmetrical the more it heels, with the lee side bulging out, creating wave drag and a weather helm, usually counteracted by a large rudder (creating more drag). Rozy II follows the Micronesian practice of keeping the "flat" side to leeward, which creates a leeward turning force (and balancing the windward turning force of the schooner rig). The flatter lines create less drag, and best of all, the waterplane shape becomes increasingly symmetrical as the boat heels, not less. Heeled to 14 degrees, the yacht's waterline beam shrinks from 53" to 44", yielding a 7.6:1 Length:Beam ratio. I expect considerably better speed from this finer and much lighter Rozinante when compared to the original.



Accommodations are spartan below, as was the original. A single berth with sitting headroom and storage locker in one end, and an enclosed head in the other. Though L. Francis would prefer a cedar bucket, I'm including a marine toilet and holding tank as a concession to modernity. The galley box is in the cockpit, running the length of the leeward side.

Rozy II is steered via trimming the sheets and adjusting the two centerplate "trim tabs". In this, she follows the practice of Yakaboo, the record breaking sailing canoe of Frederick "Fritz" Fenger. She won't be "multihull" fast, but I think she'd make for a fun and rewarding boat to sail, and the looks she would get at the dock would be absolutely priceless.

Note: This is a sketch, a cartoon only. No plans are available.

Comments

  • Now, this is what I call original thinking!

    Posted by  on  01/14  at  03:50 AM
  • That is out of the box thinking!
    Really original.
    My compliments. Looks good too.
    Cheers,
    Peter

    Posted by peter mirow  on  01/14  at  02:27 PM
  • Thanks for commenting. Always appreciated.

    Posted by Editor  on  01/14  at  06:45 PM
  • Now… this one just might keep me awake at night.  Your ideas are always inspired, but this one is just, well, ispirational.  I don’t know how you come up with this stuff, but please, please never stop.

    Posted by  on  01/15  at  02:19 PM
  • Now this is fun!

    I’ve been hovering between Nigel Iren’s Roxane (see images at http://www.nigelirens.com/FRAMEcruising.htm )
    and a Harry Proa. Yes: schizophrenic. But you all understand that. This is that boat. Something to sail in happily, speedily and safely that isn’t dragging the whole 19th century in its wake.

    What are your plans for plans, a model, a prototype?

    Posted by John Turnbull  on  01/16  at  10:12 PM
  • ... and I’d like to see more comment on the idea of steering with the unbalanced foils. My own experiment (a symmetrical boat powered by a kite) will depend on the constant adjustment of a fore and and an aft foil.

    Posted by John Turnbull  on  01/16  at  10:19 PM
  • John, I think this particular vessel will rely much more upon changing the balance of effort between the two sails than of the two submerged foils, something your kite-powered vessel likely can’t do.  The foils here just make for a gross movement of CLR to match what happens with the CE when shunting the cat-schooner rig.

    Posted by  on  01/17  at  03:05 PM
  • John - Wow, now that you mention it, you’re right! Thanks for the comment. Rozy is intended as a flight of fancy, nothing more.

    Todd - Yes, I figure gross CLR adjustments with the foils, fine adjustment with the sails.

    Posted by  on  01/17  at  03:18 PM
  • Hi Todd—Yes I agree and I should have been more specific. Changing CE will be more important than changing CLR, but I have a cunning plan! I plan ("hope") to vary the CLR both fore-and-aft as well as athwart. I plan ("hope" ...) to run the control lines through a bridle that will allow adjustment by shortening/lengthening the three connecting lines. These will connect at the bow and on both sides of the boat to the out-board ends of my rowing riggers. (Don’t worry, this is not a rowing shell—I have a little stability and freeboard.)

    Michael, if someone had time to make a model, would you mind?

    Posted by John Turnbull  on  01/17  at  04:26 PM
  • John - mind? I think it would be great. :-)

    Posted by  on  01/17  at  05:10 PM
  • Awesome! I have read a lot on this topic, but you definitely give it a good vibe. This is a great post. Will be back to read more! . Towable

    Posted by Towable  on  03/08  at  03:43 AM
  • What about chine runners or antivortex panels for this boat ? seems to be a perfect application ...

    Posted by  on  03/14  at  05:59 AM

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