Measuring junk saling performance

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  • 10 Jul 2018 23:10
    Reply # 6374926 on 4913961

    great thread, while I don't really have any curiosity about how the JR compares to the BR, I'd dearly love to see how the JR compares to the Balanced Lug and how the various JRs compare to each other and which type of JR does what best.


    I can relate to what Asmat said about the really important qualities of boats (or pretty much anything else) not being measurable, but numbers seem to impress the heck out of BR sailers.


    Bill

    Last modified: 10 Jul 2018 23:15 | Anonymous member
  • 10 Jul 2018 08:24
    Reply # 6368201 on 4913961
    I confess to being with Asmat on this one.  However, we are all different and there are certainly plenty of people who not only like 'numbers', but don't accept any explanation or opinion that aren't backed by provenance and statistics.  For these people, and for those who just like comparisons that they can repeat, these measurements will be of great interest.  Thanks to Alan for persevering with that most frustrating of things: recalcitrant electronics.
  • 09 Jul 2018 21:35
    Reply # 6367457 on 4913961

    In "The Cruise of the Nona", Hilaire Belloc wrote about  "....that craze for measurable things which has done us so much harm... When I say of the Nona: "She is a good boat", when I stroke her and she purrs, there is nothing here measurable."

    I think my  Branwen is a good boat. She carries me about the seas from place to place,  she is beautiful and I love her.  I don't think I would like her qualities to be defined through numbers.

  • 09 Jul 2018 12:36
    Reply # 6366317 on 4913961

    On Saturday we took the Mk2 water speed sensor probe out for testing and calibration. I'm glad to say it all worked, and the new probe design has overcome the problem we had with the Mk1 probe of Bluetooth not working through water. So now we are all set to do some actual testing of junk rigged boats.

    There are some videos that you can download from Dropbox here

     https://db.tt/3Fm2EbGlY7

    I have sent an email to the previous volunteers for testing asking for possible dates and locations, but if there are any other owners in the UK interested in getting some independent performance data for their boat, please contact me. Although we are primarily interested in "interesting" junk variants, we also would like to have some traditional junk rigged boats for comparison, especially of those models which are often  rigged with JR, e.g. Newbridge boats, Westerlys, Sunbirds, etc.

  • 14 May 2018 13:34
    Reply # 6159275 on 5682386
    Mark Mclauchlan wrote:

    Hello all.

     I happen to have a little 6.5m Monarch fin keel sailboat that I managed to dis mast last year. I am also in the process of trying to decide which would be the best rig (vs effort to achieve) on Stalemate which is a westerly konsort and would be pretty similar to Poppy. I would be interested in comparing cambered vs split junk rig. 

     The little boat could be on my mooring in Plymouth have two mast positions if needed to test different rigs. Would anybody be interested?

     

    Regards

    Mark


    Yes, Mark, I'm interested. let me know how your plans progress. We are hoping to have a testing session in Falmouth in September when David Tyler is planning to be there in Waeverbird, and KRKA lives there. We might be able to do some testing with you at the same time.
  • 14 May 2018 13:29
    Reply # 6159118 on 4913961

    Last week over a couple of days I tried out the JRA instruments on a friend's boat. Generally things went well, and the frame carrying the instruments did not break although it creaked and groaned a bit when the skipper tacked fast while we were creaming along at 7 knots, which generated maximum side force.

    Unfortunately we hit a snag that none of us had foreseen. We were trying to calibrate the water speed sensor in Ipswich dock where there is nice flat water and no current, as it has a locked entrance. We could run at above 5 knots for long enough, but we discovered the fatal flaw, which is that to calibrate the sensor, we have to use a Bluetooth connection, (to a phone with GPS), which worked fine when we were stationary, but stopped working once we got above 1 or 2 knots and the probe kicked up a bit of a bow wave.

    A bit of research on line led to the explanation - Bluetooth doesn't work through water. Apparently it uses a similar frequency to microwave ovens, so we were just trying to heat up the dock. I can see the system would work fine when the sensor is mounted in a boat, but it doesn't work in a probe.

    So we have gone back to the supplier to ask if there is another way to calibrate the sensor, or to get the Bluetooth signal out of the probe - an aerial maybe? No reply yet, but I guess they have their thinking caps on, or maybe they're just on holiday.

    If we can't make it work with the existing probe, I have a plan to change the probe so it sits on the water rather then in it, and has a spray rail like a fast motorboat to keep the bow wave low.

    Either way, it's going to be a while before we can sort this out, but one way or another we will sort it out. If all else fails we can change to an older simpler sensor. I will post an update when we know how we are going to proceed.

  • 14 May 2018 13:02
    Reply # 6158192 on 6120118
    Roy Denton wrote:

    Thanks for the update, Alan, it's looking promising.  If you need a 33' JR ketch with hinged battens for your portfolio I might be persuaded - once I get the RCD sorted.


    We might just take you up on that Roy! let me know when you have the RCD sorted.
  • 25 Apr 2018 20:26
    Reply # 6120118 on 4913961

    Thanks for the update, Alan, it's looking promising.  If you need a 33' JR ketch with hinged battens for your portfolio I might be persuaded - once I get the RCD sorted.

  • 24 Apr 2018 10:44
    Reply # 6117451 on 5681586
    Roy Denton wrote:
    Alan Boswell wrote:

    It may have been quiet on the surface, but we have been paddling like crazy underneath.

    Any chance of a short update on a further four months' paddling?


    I am pleased to report that as of yesterday we have got the electronics working together, so we are getting signals from the sensors to the multiplexer, and via wifi from the multiplexer to the laptop. We still have a glitch in getting the polar diagram software to accept the input via wifi, but I'm hopeful we'll get that sorted soon.

    It has taken a long time because both Chris and I have been super busy over the winter, but my 6 month contract is now finished so I have more time on my hands again. 

    The next step is to find a boat, preferably in East Anglia, that we can use to test the equipment out "in real life". It was going to be Rodney Whitworth's "Gung Ho", but sadly he has been taken ill. Tim Metcalfe has volunteered "Poppy", but she's not going afloat until 10th May, so if anybody knows of willing owner with a boat in the area (or close to it) available before then, please let me know.

  • 14 Jan 2018 18:58
    Reply # 5682386 on 4913961

    Hello all.

     I happen to have a little 6.5m Monarch fin keel sailboat that I managed to dis mast last year. I am also in the process of trying to decide which would be the best rig (vs effort to achieve) on Stalemate which is a westerly konsort and would be pretty similar to Poppy. I would be interested in comparing cambered vs split junk rig. 

     The little boat could be on my mooring in Plymouth have two mast positions if needed to test different rigs. Would anybody be interested?


    Regards

    Mark

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