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Thread: Pillar Point/Monterey round-trip under twin jibs

  1. #1
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    Pillar Point/Monterey round-trip under twin jibs

    I sailed from Pillar Point Harbor to Monterey round-trip over Thanksgiving weekend. Just thought I'd report that Ad Astra handles perfectly under twin jibs sailing downwind. When sailing within 30 degrees either side of dead downwind, jib poles were unnecessary, and steerage can be accomplished by adjusting each jib sheet's tension. I had a separate jib sheet attached to each clew.

    The twin jib configuration naturally resists deviations from a downwind heading. When the following seas would kick the stern to the side, one jib would be taken aback, causing the boat to yaw back to a downwind heading. The real beauty of the twin configuration is the ability to sail up into the wind on a close reach while allowing the windward jib to lay against the lee jib, and then easily turn back to downwind with both jibs inflated -- while never leaving my seat in the cockpit.

    There's really nothing new about this - old salts have been sailing twin jibs across oceans, but I haven't seen described the real flexibility of "sailing on any point" using the setup. Try doing that with a spinnacker! And since the twins can't swing out athwart, there's no danger of a "roll of death" oscillation developing. In fact, there's very little rolling at all.

    I had following seas both ways: northbound and southbound, because I timed the return while a low was developing into a storm offshore, giving me southerly wind and seas for my return.

    I was able to surf on the following seas and achieve a speed over ground of 8.6 knots with 15 knots relative wind. Exciting! I'm attaching the track and speed plot from marinetraffic.com.

    You can follow Ad Astra on marinetraffic.com here: https://www.marinetraffic.com/en/ais...444883/zoom:14
    Attached Images    
    Last edited by pbryant; 11-29-2017 at 10:07 AM.

  2. #2
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    Best to post a link to the videos

  3. #3
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    Exclamation Exillerating!

    How did you rig the second jib.

    Have you a furler?

    More photos are mandatory!!!

  4. #4
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    I had my sailmaker (Leading Edge) make a jib identical to one I had, with the hanks staggered. He did such a good job that even the luff tensions are identical when the twins are hoisted. I've only once seen that accomplished with a roller furler: the owner had two light jibs that would roll up together, so when fully unfurled you had the equivalent of twin jibs. It was 30 years ago, and my memory is foggy on how he did that.

    The small air gap between the luff edges at the forestay seems to improve stability, much like the apex vent in a parachute reduces oscillation. The temptation is to seal it somehow, but I believe it's beneficial and has little effect on efficiency. At any rate, I was surfing along well above hull speed, my hand off the tiller, with the boat not rolling and standing straight up, so I can't complain.
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    Last edited by pbryant; 11-28-2017 at 07:14 PM.

  5. #5
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    Riding on the storm!

    Here's a pic of the developing storm offshore with a well-defined eye at the center of the low. Timing is critical. Enter too late, and the seas will chew you!
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  6. #6
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    Thumbs up Ahhh. h. h. h. h ...

    ...THAT'S much betta !!

  7. #7
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    storm chew

    but you're scaring the hell out of some people here...

  8. #8
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    I don't flirt with storms once they've developed, but I will take a push from one while it's still spinning up. Timing is everything.

    The conditions were quite benign: the wind waves had laid down entirely in the lull, winds were 8 knots (apparent) out of the south, and a long period southerly swell astern allowed me to surf all the way home. Eight hours later, the conditions would have been very unpleasant.

    I'm commercial pilot and fly gliders. I trust my eye for reading the clouds -- the "sign posts in the sky." Without that experience, I wouldn't advise beginning a voyage with a storm in the forecast. We have the advantage here on the West Coast that storms seldom develop quickly -- and I still had my eye on ducking into Santa Cruz or Aņo Nuevo anchorage as a Plan B. The most critical part of the passage is crossing Pigeon Point and Aņo Nuevo. If you see what looks like fog ahead - when conditions don't call for fog - then that's spume thrown up by the chruning washing machine sea state often found between those two points brought on by cross seas. I've seen waves arriving there out of both the north and south, slamming together to produce great triangular-shaped swells with sharp sides that lofted my boat in the air. This voyage - it was as smooth as concrete.

    I trailed my Hamilton-Ferris hydrogenerator prop to prevent surfing faster than my comfort level (and to generate 10 amps for my batteries). You can see the trailing line in the photo below. The drag on the line is progressive, with nearly none (only parasite drag) below 4 knots, and about 100 pounds of induced drag at 8 knots.

    One thing I always do that I'd recommend to anyone who can read weather charts, is to review the Pacific Briefing Package (http://www.opc.ncep.noaa.gov/shtml/P_brief.shtml) before embarking. It gives a big-picture view of synoptic winds and sea states that you can't get from the Coastal Waters Forecast. Grib charts are nice (albeit often inaccurate), but they don't show the underlying dynamics or sea states.

    I also monitor the Automated Weather Observation Service (AWOS) for an airport up ahead with my aviation band radio, or by cell phone (when it works) to answer the question: "does it get better or worse up ahead?" Half Moon Bay is 127.275 MHz (650-728-5649), and Monterey is 119.25 MHz (831-642-0241).
    Attached Images    
    Last edited by pbryant; 11-29-2017 at 01:15 PM.

  9. #9
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    Sep 2001
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    skip the fries

    Metaphorically, thanks for putting some lettuce back in the hamburger --

    Personally used to your pickle and mustard -- OK with that --

    You know, leaving out the greens, tomato, onion, mayo, all the juicy stuff --

    Can see now, how you meet with raw nature with such certainty, bravado

    and smarts, really impressive.

    Thanks for filling us in. Thanks for sharing. Feel like a shore bird taking a

    break on your boom there...
    .
    .
    .
    Last edited by ebb; 11-29-2017 at 01:50 PM.

  10. #10
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    Thanks Ebb. But no matter how hard I try, I could never fill in the blanks to express in words the mysterium tremendum of being at sea.

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