RSS Forum – latest posts

  • Instrumentation & Control • Re: Accuracy of GPS speed measurement
    I have come to the conclusion that, based on specifications from receiver manufacturers, GPS speed measurement is not sufficiently accurate for drag measurement by towing. I have considered a couple of alternatives:1) measurement of speed at a shore mounted winch that is doing the towing2) measurement of speed by timing between start and finish lines […]
  • Events & other announcements • Catalyst 55
    ... can be downloaded from the Members area of the AYRS Forum - viewtopic.php?f=37&p=3514#p3514.(If you have not done so already, you will need to be verified as a paid-up AYRS member before you can access this. Message the AYRSWebadmin).Statistics: Posted by AYRS Editor — Fri Oct 11, 2019 11:27 am
  • Instrumentation & Control • Re: Accuracy of GPS speed measurement
    Hi FredMy understanding is that GPS determines speed by a method that is fundamentally different to the method by which it determines position. Hence knowledge of the positional accuracy does not necessarily tell us much, if anything, about speed accuracy. The American government provides information about the accuracy of GPS here:https://www.gps.gov/systems/gps/performance/accuracy/Looking at the above web […]
  • Instrumentation & Control • Re: Accuracy of GPS speed measurement
    I believe that over a reasonable distance(?) it is accurate but the best GPS units are I think differential and accurate in position to cms where as older (and ? cheap chips ) accurate to 15 metres so the speed may be in error but it may be worthwhile as then on has automatic speed […]
  • Instrumentation & Control • Accuracy of GPS speed measurement
    Can anyone tell me about the accuracy of GPS speed measurement - I ask because I am wondering if it is worth including GPS speed measurement in the unit I built to measure the drag of towed hulls at the recent AYRS event at the Bassingstoke Canal Centre - see posts here under 'Events'.The American […]

The Split Junk Rig

Back in 2002, AYRS Member Slieve MacGalliard was looking for a way to improve the one weak point of the modern western Junk rig – the windward performance. His conclusion was that camber is needed right to the luff of the sail, a feature that is difficult to achieve with the standard rig, which is normally pulled aft. One possible idea was to build a cambered rig with a lot of sail balance forward of the mast and split the sail in way of the mast so that the camber would be the same on both tacks and not distorted by the mast.

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