Measuring junk sailing performance

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  • 25 Jun 2017 13:10
    Reply # 4916629 on 4913961

    Alan

    You are on strong ground at least financially in asking for such a project to be at least considered.   

    At AGM 2014 the Committee put forward a paper on the financial management of the Association which was formally approved by the members.  The document is still available on the web site under JRA Documents. It included:

    "Rather, we believe that the general reserves should be used towards significant projects in pursuit of our Aims and Objectives. We wish to encourage such projects. Some possible projects might include: 

    • further digitisation of the books in our library; 

    • production of supplements to Practical Junk Rig; 

    • publication of a history of the development of the western junk rig; 

    • production of videos of modern junk rigs in action; 

    • further computerisation or digitisation of our proceedings; 

    • j u n k r i g r e s e a r c h a n d development; 

    • etc, etc. 

    If we are successful in encouraging such projects, there could be significant expenditure and hence a reduction in our general reserves ie an excess of expenditure over income for the Association as a whole. We believe that this should not then be viewed as a “loss” but as a gain in terms of our useful activities."

    And our Constitution 2012 states:

    "The Aims and Objects of the JRA are: 

    3.1 to promote and encourage discussion of junk rig (JR), including its traditional use, its design, and developments of it, and of the building and use of vessels with such rigs and their derivatives. 

    3.2 to facilitate contact and communication between members of the Association."

    Good luck and Fair Winds

    Jonathan 

  • 25 Jun 2017 12:29
    Reply # 4916622 on 4913961
    Anonymous member (Administrator)

    Hi Arne,

    If people can find the opportunities to race, and want to do it, that's fine. I'm all for it, but it only gives us a small amount of data, and of course is highly dependent on how well the boats were sailed on the day.

    What I am trying to get across is that the technology now exists to use standard boat instruments to collect data, and then analyse it in an objective way. A quick search on the internet came up with this site as an example of what can already be done.

    http://www.sailingperformance.com/RaceReplay.html

    Obviously it is aimed at the racing fraternity, as they are the ones with enough interest and money to make buying these products worthwhile. Clearly there is a lot more research needed into the hardware and software required, but that is presumably something the proposed technical sub-committee will be interested in doing.

    If you watch the training videos on the website above, you will understand that operating the software is not that hard, and that it allows you to analyse data collected over a whole season.

    I think the potential here is enormous and offers us the opportunity to collect factual and objective data on the performance of almost any boat and rig.

  • 24 Jun 2017 17:59
    Reply # 4915843 on 4913961
    Anonymous member (Administrator)

    Alan,

    one race is not enough, but after 5 – 10 races one may calculate average sailing times and even out results from good and bad races.

    One may think that the human factor can be eliminated by filling the boats with instruments, showing and logging wind data and the boat’s speed and leeway as well. However, it would be next to impossible to monitor the sheeting and twist of the sail. I have been out in my IF, Ingeborg, nine times the last month. These were short trips where I did my very best to sail well to windward, as well as on the other legs. I notice how only small changes in sheeting may add or rob almost half a knot, and that is on a quite forgiving vessel.

    Therefore, I still think that racing against a group of the same boat type is the best way to assess one’s JR.

    If one wants to spend some of the JRA funds on R&D, then I suggest this:
    Look up yacht clubs where they hold regular club races with (not too big) one-design boats. Arrange with a few of them to let you rig a boat of the same design with your favourite JR, and then participate in the summer series of their races.

    I could well vote for spending some of JRA’s money on subsidising the construction of a few junkrigs for this cause. The owners’ payback would be to complete the race series and make the results available.

    I am sure Edward Hooper already has enough data to make a useful comparison between his Amiina and the other Splinters in the club.

    Arne


    Last modified: 26 Jun 2017 09:19 | Anonymous member (Administrator)
  • 24 Jun 2017 15:57
    Reply # 4915715 on 4913961
    Anonymous member (Administrator)

    Well, nice to see a bit of discussion on this. A match race between identical boats with different rigs is always going to be interesting, but there will always be unknowns like how good are the helmsmen, and was the set up optimised on both boats.

    I agree with Arne that it is virtually impossible to get group races between matched boats with different rigs, but one design racing is the best opportunity to match the JR against Bermudan, and again always interesting to see what happens, although with the same caveats about all the unknown variables like helmsman, rig set up, and tactical choices during the race, fickle light airs conditions, wind shifts, etc....

    That's why the best way to compare rig performance is to record actual boat performance data, but not as isolated boat speed versus wind speed and wind angle data points, but by generating proper polar performance diagrams in the same way that race boats use computer generated polars to check their performance on the water against what they should, in theory, be achieving.

    The technology exists for them to do this, so there is no reason why we can't do the same thing, except money, and that is where the JRA can perhaps step in. It is embarrassing that the JRA has reserves of over £30,000, largely due to the gift and subsequent sale of KRKA, and this money should, I think, be put to a good use. I do think that enabling us to put some solid numbers on the performance of junk rigged boats is a worthwhile cause for the JRA to support financially.

  • 23 Jun 2017 22:07
    Reply # 4914949 on 4913961

    Well hopefully we will soon see a bit of a match race between 'Footprints' and the newly re-rigged 'Shoestring'. Footprints and Shoestring are sister-ships, although each with a slightly different interpretation of the plans. Footprints has a lower aspect camber panel sail, and Shoestring the taller flat, McLeod/Hasler sail. So we may get some idea of the merits and capability of each type of sail.

    It will be a match-race of epic proportions and I am sure will eclipse the Americas Cup racing in terms of excitement and spectator appeal!!  


  • 23 Jun 2017 21:32
    Reply # 4914737 on 4913961
    Anonymous member (Administrator)

    Alan,
    you know, this is not easy to arrange. It is next to impossible to arrange a line-up of three or five identical boats with all sorts of junk rigs, and then compare them in a series of races. Moreover, reporting instrument readings only are of little interest as the conditions vary so much.

    Now I got an idea for a second-best, but hopefully realistic method:
    Since many junks are modified from BR, and since some of these Bermuda-rigged boats are still being raced, one could join these races just to see how one’s boat with JR compares. After five or ten races, one could even calculate the average speed of the pointy rig sailers (same class) and compare it with the average speed of the boat with a JR of this or that sort. This would give a good hint on how this or that JR performs against the standard  -  the Bermuda-rigged boats.

    Edward Hooper should have plenty of such statistic material available after having raced Amiina. I am sure there are other classes too, like the Hunter 19 Europa and Contessa 26, which are being raced each week. If one could join them, a really realistic comparison could be made.

    Now I must check if any IFs are participating in the Wednesday regatta series in Stavanger. If yes, then I may overcome my reluctance to race, just for the sake of science. I would of course accept any impossible handicap, as I would only be interested in the elapsed time of my boat and the other IFs.

    Arne


  • 23 Jun 2017 11:44
    Message # 4913961
    Anonymous member (Administrator)

    As reported in JRA Magazine 74, Pete Hill suggested (Item 10d) that the Committee "set up a technical sub-committee to investigate the performance of all the various rigs that are being developed." He also volunteered to head up the sub-committee.

    I strongly support this initiative and I would like to volunteer to assist on the sub-committee.

    Here are a few initial thoughts to stimulate a bit of discussion on this topic.

    1. We did this 20 odd years ago and sponsored Joddy Chapman to research the subject. There are various articles abut this in Magazines 30 to 39 (Summer 1995 - Mar 2002). I believe that as a result the JRA already owns a set of measuring equipment for this purpose. This may be of use to boats with limited instrumentation, although I suspect the equipment is now very dated.

    2. Instrumentation has come on a long way since then with many boats now having their own instruments providing the key data such as true and apparent wind speed and direction, boat speed, boat heading (from autopilot), and GPS speed and direction. I believe that it is now possible to acquire data loggers and software that will allow this data to be collected automatically and converted into a sailing performance chart. I suggest the JRA should investigate and perhaps purchase such a system which could be moved from boat to boat.

    3. Some pitfalls need to be avoided. Personal reports of the performance of a boat which are not supported by good data are inevitably subjective and not very reliable. Even when supported by data, the recorded performance will rarely represent the maximum performance of the rig and boat, so extensive testing is required to achieve and record the best performance over a range of wind strengths.

    4. Comparative testing on identical boats can be useful, and we used this in the early stages of Sunbird's existence, as both Robin Blain & I had Lasers. However, on small boats the effect of the fitness and skill of the helmsman has a big effect on the performance of the boat, and so helmsmen need to swap rigs or boats fairly frequently to get meaningful results.

    That will do for now. I shall be interested to see how things develop!

    Last modified: 23 Oct 2018 16:08 | Anonymous member (Administrator)
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       " ...there is nothing - absolutely nothing - half so much worth doing as simply messing about in junk-rigged boats" 
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