Measuring junk sailing performance

  • 03 Jul 2017 21:33
    Reply # 4930388 on 4913961

    I see the handicappers gave you a benefit compared to her, (TCF of .776 against .821) of about 5%, which I guess reflects their assessment of the rig, but the results suggest it is about right. Does she have a spinnaker, and did she use it?

    The handicappers will never release their formulae, probably to stop distorted boats being built to cheat the rules. There was enough of that back in the 1970's with the IOR boats and ultimately the '79 Fasnet race.

    Having said that, from my original dealing with the Island Sailing Club and a handicap for Poppy I understand that they are making no special allowance for the rig being junk (pun?) and after discussion are simply taking the total sail areas in front and aft of the mast. Most Bermudan boats have unmeasured sail area in the roach of the mainsail, and possibly foot of the headsail, but the split junk has none, and actually has significant hollow which is included in the measured area. The rest of the formula seems to based on simple measurements and weight calculations. You get a very good handicap if you give Thames Measure instead of Gross weight, but then they find out about it and cut you down to size. I understand the differences in the Splinter's handicaps is due to their different displacements, and the areas of each sail, remembering that the Bermudan boats were flying spinnakers, the area of which is probably added for a %age of the race.

    Considering that the Bermudan sails have been tweeked over many decades for the racing circuit and that Amiina's sails were built on the family room table I still reckon we're on the right track. I'll bet they were the highest placed boat with home made sails.


  • 03 Jul 2017 19:04
    Reply # 4930176 on 4913961

    Well done Amiina! Well done Edward and Steve!

    So what do the race results show us? We must remember that with some 1300 boats sailing the course that the smaller boats starting at the back of the fleet always end up in very choppy water, particularly when they get wind over tide behind the bigger boats. This favours boats with hull shapes similar to the FolkBoat, which always place well in the race, such as the SCODs, Contessa 26, FB, and this year's first small boat home, the Alan Buchanam East Anglian which was second overall. Handicapping takes no account of this disadvantage for the smaller and lighter boats.

    650 boats crossed the start line in the ISC Rating System fleet. 41 failed to post a result for a variety of reasons. Amiina placed 106, which is 106/650, (16%) or in the top 6th of the fleet. This is a very creditable performance. Looking more closely at boat for boat comparisons, there were 2 other Splinters in the race, both serious racing boats. Elfin apparently is now competing with Whisper for top line honours in their club fleet, and was planning of flying her big spinnaker and came 21st on Saturday with an incredible performance. Sparkly, another keenly raced boat, and probably flying her smaller spinnaker placed 103 and beating Amiina by only 37 seconds on corrected time (after over 10-11 hours of racing). In other words, with her junk rig the cruising Amiina is right in there with the Bermudan rigged racing boats.

    As expected the SCODS and most of the Contessa 26s beat Amiina, but not all, and the 2 FolkBoats only beat her by one and a half minutes and ten and a half minutes. Interestingly she beat both Bermudan rigged Hunter Horizon 23s, as well as both Hunter Sonatas!

    Overall, it was a most creditable performance. 'The boys Done Gud'.

    Perhaps it would be worth mentioning just how much effort is involved in completing the race. Apart from preparing the boat, there are logistical problems caused by the tides around the south coast. Edward left his home berth single-handed on Wednesday and should get back this evening. In between he has had help from Anthony Cook and Sally and Steve Peake, and Steve sailed the race with him. So overall we're talking about 6 days of steady work and significant cost on top of the race fees to get the performance comparison to the rest of us. Did I mention the Brownie points as well? Edward deserves a very big Thank You.

    I've posted this on the 'Measuring Junk Sailing Performance' thread (and perhaps it should be copied into the racing thread), simply because it shows what some members are doing, and have been doing without sponsorship or help from the Association. All the useful development work and rig improvements have been done by members who give so freely of their time and effort, and at their own expense. I believe it would be wrong for the Association to sponsor test equipment to assist those who have made financial gain from their involvement with the JRA when the average member stands to gain very little if anything for the expenditure.

    If anyone wants test equipment then they can either make it cheaply or buy it out of their own pockets, as the rig developers have done.

    Cheers, Slieve.


    Last modified: 03 Jul 2017 21:34 | Anonymous member
  • 03 Jul 2017 16:05
    Reply # 4929926 on 4913961

    Well done Edward!

  • 03 Jul 2017 11:33
    Reply # 4929608 on 4913961
    Anonymous

    Well done, Edward! You must be pleased to have matched Sparkle, at least on handicap which means you must have sailed as well as them over the whole course.

    I see the handicappers gave you a benefit compared to her, (TCF of .776 against .821) of about 5%, which I guess reflects their assessment of the rig, but the results suggest it is about right. Does she have a spinnaker, and did she use it?

    There ought to be a prize for the first person to finish (on handicap) in carpet slippers (as per Jock McLeod in Ron Glas)!

    Are you up for some data collection on Amiina?

  • 02 Jul 2017 20:09
    Reply # 4928837 on 4913961
    Deleted user

    Ref sailing performance, herewith an email just received from Anthony Cook that details

    Amiina's performance in yesterday's Round the Island race. 

    ""Morning All


    Don't know whether you have access to Excel, but the attached is an analysis of the results.  The first tab, 'All' shows everyone in the race.  The second tab, 'ISC' shows just those boats in the ISC divisions, from which  I have excluded any that didn't finish, or were disqualified.


    Assuming I have interpreted the figures correctly, Amiina was 21st out of 46 in Div 8D, 41st out of 136 in Div 8, and 106th out of 609 in the ISC group.


    I call that a pretty good result!


    Anthony"


    Anthony has also downloaded the Results pages from the Island Sailing Club

    from which all the technically competant can see the details 

    of each boat and their relative performances over a 56 mile  round course

    full of differing conditions and complex waves and tides. The link will be posted as soon as i learn how to do it. 

    Cheers

    Edward

    Last modified: 02 Jul 2017 21:08 | Anonymous
  • 02 Jul 2017 15:56
    Reply # 4928653 on 4913961
    Anonymous

    Thanks for the latest positive suggestions from David and Rob.

    I have just emailed a proposal to the Chairman & Hon Sec for them to deal with as they see fit. There are some interesting alternatives available ranging from around £1200 to a maximum of £2600 and these figures include wind and boat speed instruments, a recording device, and some analysis software.

    We could spend less by using members computers, tablets, or phones as recording devices, and cheap(er) software, but the instruments and mounting pole(s) will cost at least £600 for off the shelf units and metalwork.

    No doubt the proposal will end up being posted somewhere, and at that point you will be able to see the details, and pick it to pieces. It is by no means absolutely comprehensive, but I reached the point where I was spending more and more time researching ever finer details, and I felt diminishing returns had set in.

    I hope you will be able to see it soon.

  • 01 Jul 2017 02:03
    Reply # 4927231 on 4913961

    David,

    I think it would be very worthwhile and it is fantastic that you have volunteered to use Weaverbird to get the testing underway. On talking to Pete before he left he rattled off no fewer than 14 possible rigs that we could test!!

    To move this along, maybe we need Alan to specify the testing process, the test equipment and a cost so we could discuss it as a committee and on the fora to see whether we want to proceed or not.

    Rob



  • 30 Jun 2017 08:16
    Reply # 4925722 on 4913961

    Rob, 

    I was assuming that Alan would be specifying a set of instrumentation in a form that could be fitted to any boat, and that the JRA would fund it and make  it available to me and to others.

    My plan would be to make a comparison between my current rig and a wingsail. The mast position could accommodate a Sunbird sail, designed by Alan and made by Exe Sails, or a sail designed and made by Arne, thus making it possible to run comparative tests on four different types of sail, if that were thought to be a worthwhile thing to do? 

  • 30 Jun 2017 06:25
    Reply # 4925694 on 4913961

    David, 

    I cannot believe that you are going to build another rig for Weaverbird! You are just amazing. Will it be possible to measure Weaverbird's current performance before you change? Do you need some special instruments that maybe the JRA could contribute to? Could Alan or others use the same instruments?

    Alan, 

    On behalf of Pete Hill, who is currently on route to French Polynesia, we would welcome you onto the technical sub committee and look forward to your expertise. Pete will be back in New Zealand in 6 months time but I'm sure we can move things along in the meantime.   

    Rob

  • 29 Jun 2017 10:29
    Reply # 4923498 on 4923407
    Anonymous member (Administrator)
    David Tyler wrote:

    Now I have a boat for which a wingsail would be a more achievable proposition, at a smaller size than was the case with Tystie. I could make a wingsail this coming winter, to the same planform as my current sail. I have enough cloth for the sail, and could reuse most of the hinged battens that are in the current sail. I think this would be a worthwhile comparison - same area, same planform, same camber, but one sail with a sharp leading edge and exposed, draggy mast, the other with a better foil section, a rounded leading edge and a concealed mast.

    But I would need a self-contained wind and water sensor setup, at either end of a long tube that I could lash to the bow. Anyway, I've always felt that masthead anemometers are not much use in a seaway, when the masthead is describing wild circles.

    David,

    I bet your Duette is just the right boat to be used as a rig testbed. Still, before you change your rig, I hope you get in some sailing in company with original Duettes or Sonatas.
    The proof of the pudding is  -  the match-racing.

    I agree with you that masthead anemometers are not the best. Apart from flying around up there, they tend to see much stronger winds than I sense in the cockpit. Quite a few times, when I have been out sailing in a breeze, other sailors around me report about gale-force winds...

    Arne



    Last modified: 29 Jun 2017 16:41 | Anonymous member (Administrator)
       " ...there is nothing - absolutely nothing - half so much worth doing as simply messing about in junk-rigged boats" 
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