Win Bucket List for a day or $500. How fast will it sail?

Discussion in 'Boat Design' started by rob denney, May 29, 2016.

  1. rob denney
    Joined: Feb 2005
    Posts: 737
    Likes: 105, Points: 43, Legacy Rep: 436
    Location: Australia

    rob denney Senior Member

    After any teething troubles are sorted out, Bucket List will be sailed upwind and reaching. The gps recordings will be shown on http://harryproa.com/?page_id=1620

    Upwind: It will be sailed upwind for 5 minutes, shunted, then upwind on the other board for 5 minutes. What will be the distance between the start and finish points?
    Answer in nautical miles to two decimal places. eg, if it sails at 10 knots upwind and tacks/shunts through 90 degrees the distance between start and finish will be 1.17 nautical miles, Tacking angles less than 90 degrees will increase the distance.
    Reaching: It will be sailed on the fastest point of sail. What will be the max speed? Answer in knots to one decimal place. eg 23.6 knots.

    The location is the stretch of open ocean south of the Seaway, Gold Coast, Australia. 5 speed runs will be performed at varying windspeeds, at least one of them with the wind at The Spit weather station (http://www.seabreeze.com.au/graphs/qld4.asp) reading over 20 knots.

    The prize is a days sailing (racing, cruising or just hooning around) on the prototype which would normally cost $AUS500. You can use it, cash it in after the boat’s first ‘charter’ or donate it to charity. The prize can be claimed on the Gold Coast or where ever the boat travels.

    The winner will be the person who gets closest to the upwind distance. In the event of a draw, the top speed will be used as a tie break. If more than one entry gets both numbers correct, they will all get a free day.

    One entry per email address.
    Your initials will be used in the "entrant name" column unless you ask for your name to be entered.
    Revise/update your entry as often as you like. Follow the rest of the build progress on the blog for updates on weights, launch date, etc.
    Your contact information may be used by us to email you updates on Bucket List. It will not be used for any other purpose. Please let us know if you don't wish to receive updates.
    Entries close the day of Bucket List's maiden sail. This is expected to be in August this year.

    For information on Bucket List see:
    https://www.youtube.com/watch?v=ttXu3pRTzs8 video explaining the boat
    http://harryproa.com/?page_id=1173 web page
    http://harryproa.com/?p=424 build blog

    Email your entry to harryproa@gmail.com and it will be added to the list at the bottom of http://harryproa.com/?page_id=1620 Feel free to add a comment or ask any questions.
     
  2. sigurd
    Joined: Jun 2004
    Posts: 827
    Likes: 8, Points: 18, Legacy Rep: 65
    Location: norway

    sigurd Pompuous Pangolin

    I question that you can go higher upwind by moving the boat sideways through the water like the website says. Are you sure?

    Is the picture misleading me or is that an asymmetric ww hull? Why? Do you think a hull has a better L/D than a high AR rudder?

    Cockpit. No fairing.

    Looks like a lovely boat though.
     
  3. rob denney
    Joined: Feb 2005
    Posts: 737
    Likes: 105, Points: 43, Legacy Rep: 436
    Location: Australia

    rob denney Senior Member

    Absolutely. Fore and aft rudders used judiciously will move you upwind (or off a jetty against the wind) but at a diminished speed. The vmg is lower. It is possible that small amounts of "crabbing" will give better vmg, but you would need two boats sailing side by side to work out the best angles.

    The picture is misleading you. The hulls are symmetric. The gains from assymetric hulls are not worth the effort, and they are slower than a high AR rudder.

    It is in the lee of the windward hull so should not see wave impacts except when motoring directly upwind. We decided it was more important to be able to store it inside the hull so we could get 4 noats in a container than worry about the fairing.

    Thanks. I look forward to seeing your estimates of the speed.

    The first 5 entries are now on http://harryproa.com/?page_id=1620
     
  4. sigurd
    Joined: Jun 2004
    Posts: 827
    Likes: 8, Points: 18, Legacy Rep: 65
    Location: norway

    sigurd Pompuous Pangolin

    Rudders
    I read in another thread that the rudders are 0012 sections, but from looking at the video I assume that the rudders are proa sections and the front one is locked by a clamp on the tiller extension, or by sliding backwards into a notch. Confirm?

    Crabbing
    What I meant to say: I read the site as though you said that pointing the bows off the wind (relative to the course through the water) would bring the course closer to the wind, which is not the case unless you weren't able to sheet on hard enough in the first place.

    Malapropos, crabbing the other way, with the bows pointed closer to the wind than the course, could increase the L/D for instance if you were slow enough that the rudders were stalling. We agree that designing for windward lift from the hulls are probably not going to be worth it, this is just a fringe case of pinching at slow speeds.

    Kites
    The old Phantom series of Peter Lynn is one favorite for boats. Super stable things, the big ones will rest at zenith. They don't have a bridle and they can be stacked. The Flysurfer Speed is much more powerful - this and the light fabric of the Deluxe version makes it able to fly in less wind. The drawback with mine at least, is that it will deflate much faster than the other ram kites I've tried (including a standard Speed) when laying in the water. Could be a fluke.

    P.S. I suddenly got a Deja Vu. Sorry if I wrote all this before.
     

  5. rob denney
    Joined: Feb 2005
    Posts: 737
    Likes: 105, Points: 43, Legacy Rep: 436
    Location: Australia

    rob denney Senior Member

    Initially they were 2 way sections, but the one way 0012 is easier to use, so we have changed to it.

    Negative leeway from fore and aft rudders looks good in theory, and certainly works in terms of moving the boat to windward. But, the times I have tried it, the speed drop has been considerable and there have been some peculiar effects. Definitely worthy of more experimentation, but the gains are so small that 2 boats are required for side by side testing to see what is happening.

    I am looking for a second hand 24 sq m Phantom for these reasons, although all the ram air PL kites have excellent auto zenithing. Rapid deflate is a good thing when it is time to get them onto the boat, dropping it in the water is not recommended from a boat as the boat drift makes relaunching difficult.

    Only some of it;-)
     
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