Dinghy speeds

   Though GPS will not be very accurate for speed it’s not to bad for distance. Why not use GPS to sail a suitable distance from a buoy in the course relative to the wind you would like to test and drop a second buoy. Then simply sail and time. The longer the distance the more accurate. 

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tink Send Private Message Find Member's Posts Visit Member's Homepage Really should get out more Joined: 23 Jan 16 Location: North Hants Online Status: Offline Posts: 789	Post Options Post Reply Quote tink Report Post Quote Reply Topic: Dinghy speeds Posted: 08 Jan 22 at 7:27pm
	Though GPS will not be very accurate for speed it’s not to bad for distance. Why not use GPS to sail a suitable distance from a buoy in the course relative to the wind you would like to test and drop a second buoy. Then simply sail and time. The longer the distance the more accurate.
	Tink https://tinkboats.com http://proasail.blogspot.com

eric_c Send Private Message Find Member's Posts Far too distracted from work Joined: 21 Jan 18 Online Status: Offline Posts: 382	Post Options Post Reply Quote eric_c Report Post Quote Reply Posted: 08 Jan 22 at 6:14pm
	20 knots is about 15 times faster than my garden shed, according to GPS. The shed is firmly bolted to concrete foundations. GPS, in amateur hands is essentially unsuitable for measuring speed. Especially low speeds over short durations. Which is a shame really. It would be nice to know how fast my Laser was really going in those crazy surfing moments, although I'd never have the time (or presence of mind) to look at the readout.

Wiclif Send Private Message Find Member's Posts Groupie Joined: 04 Oct 05 Location: United Kingdom Online Status: Offline Posts: 81	Post Options Post Reply Quote Wiclif Report Post Quote Reply Posted: 08 Jan 22 at 5:51pm
	My speedpuck gave me a reading of over 120 knots, with a couple of others of 70 plus, when out sailing in my K1. Of course i believe it, though thousands wouldn’t

iGRF Send Private Message Find Member's Posts Visit Member's Homepage Really should get out more Joined: 07 Mar 11 Location: Hythe Online Status: Offline Posts: 6499	Post Options Post Reply Quote iGRF Report Post Quote Reply Posted: 08 Jan 22 at 4:37pm
	Oh for sunny weather again, nice video, if I could have found a reliable crew, think I'd like to use an 800 they're great boats. Only time I've been really quick in a dinghy is with a crew, once in a very strong offshore wind in an L3K only time I think I've ever actually fully planed upwind, and the other time down the back of the Round Sheppy Island race, so fast in fact it literally stripped all the gel coat off the bottom of the Alto. We don't often get conditions conducive to real speed, waves and chop get in the way, significant I can still remember those two incidents both with my dear departed windsurfing friend and crew God rest his soul, Steve Avery never since. Fstest I've been wind assisted is on a windsurfer or kite, other than that I once got dragged water ski racing at 80 + mph on a massive twin rig a long long time ago, that made my eyes water. lol.
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423zero Send Private Message Find Member's Posts Really should get out more Joined: 08 Jan 15 Location: United Kingdom Online Status: Offline Posts: 3420	Post Options Post Reply Quote 423zero Report Post Quote Reply Posted: 08 Jan 22 at 3:30pm
	https://www.yachtsandyachting.com/forum/forum_posts.asp?TID=237&PN=1&title=fastest-dinghy Above link from 2004, 24 pages, no abusive comments, this post today, would be met with abuse and derision, how times change.
	Robert

423zero Send Private Message Find Member's Posts Really should get out more Joined: 08 Jan 15 Location: United Kingdom Online Status: Offline Posts: 3420	Post Options Post Reply Quote 423zero Report Post Quote Reply Posted: 08 Jan 22 at 3:27pm
	See following post, this one removed due to formatting issues. Edited by 423zero - 08 Jan 22 at 5:23pm
	Robert

Mozzy Send Private Message Find Member's Posts Far too distracted from work Joined: 21 Apr 20 Online Status: Offline Posts: 209	Post Options Post Reply Quote Mozzy Report Post Quote Reply Posted: 08 Jan 22 at 2:28pm
	So here is an example from the 800. Breeze was about 25 knots. Here is pretty much raw footage for a 1:43 run which includes a gybe (just cropped the mast cam so overlay it). GPS recorded on a garmin Fenix with glonass and smart recording (just realised I haven't changed it to 1 hz!). So take it with a pinch of salt, I stopped using GPS for analysis as without doppler and 30 hz it's pretty difficult to draw any conclusions. But I just putting it forward as an example of pretty smooth and non-peaky data. Link to activity Before the gybe (46s) max speed is 37.8 kmh (20.4 knots) and average is 37 kmh (19.97). For the full 1.43 max is the same an average is 35 kmh (18.89 knots) over a distance of ~1 km. That includes a drop down to 16.9 kmh during the gybe. I wouldn't be claiming any concrete top speeds from this, but it is a decent example of what okay data might look like. compare with the aero speed trace RS800 full run with gybe

iGRF Send Private Message Find Member's Posts Visit Member's Homepage Really should get out more Joined: 07 Mar 11 Location: Hythe Online Status: Offline Posts: 6499	Post Options Post Reply Quote iGRF Report Post Quote Reply Posted: 08 Jan 22 at 12:44pm
	There's a reason speed records get set at Weymouth over a 500 mtr course. Those recordings anyone who goes for GPS speeds will tell you are likely as not spikes, probably caused by pitching in dinghies, I very much doubt either our Albacore which tbh nobody took any more seriously than they take the Aero actually acheived that speed. I'd recommend any of you do a Weymouth speed trials, it's great fun, and there are prizes for the fastest mono and cat and daily prizes, which are interesting in boat/board speed over wind speed, I had three great years messing about doing it. If I were RS I'd have someone do it and see if any harbour records for mono hulls could be broken. Actual speed over water as we all know can get quite exhilerating to the point of scary, but the camaraderie and 'after you henry' attitude the competitors have down there compared to the normal battle for start line space is refreshingly gentlemanly and occasionally eccentrically so. Edited by iGRF - 08 Jan 22 at 12:59pm
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Mozzy Send Private Message Find Member's Posts Far too distracted from work Joined: 21 Apr 20 Online Status: Offline Posts: 209	Post Options Post Reply Quote Mozzy Report Post Quote Reply Posted: 08 Jan 22 at 12:16pm
	there is a lot that's suss about the aero top speed. - Track looks very shaky, suggest large GPS error. - Speed graphs look peaky (27 mph down to <15 then back up again all within a few seconds) - Short runs (0.3 miles) - Seems other recording were done on a Garmin Edge 520 he has. I have used this to, but without a good gps fix on glonass satellites and recording set to 1 hz then it's pretty useless for speed. It's designed to be used with a bike wheel speed sensor. - max speed on a doppler device for same class is 20.6 knots (and that was speed a 1 second peak over a knot more than the speeds a second either side). On both the windsurfer and 800 for a 1 km run top speed will only be about 10-15% more than average. Here we have doublings of speed. That could just a characteristic of chasing huge gusts in mega wind in a small uno sail though. My windsurf speeds and 800 speeds are all done at a fairly narrow AWA. The aero's can get out in massive conditions though (although to be fair so can I on windsurf kit). But the 800 I wouldn't really be leaving the beach in 30 knots. So perhaps it's plausible, but the evidence for the 23.9 knots isn't rock solid. I think you could improve class speed competitions like this by just asking for 1 hz data and have peak speed defined as 2 seconds and then have a 10 second record too. 10 Seconds would be short enough that you don't fall out of an gusts, but long enough to have some confidence in the data (at 1 hz).

Grumpycat Send Private Message Find Member's Posts Far too distracted from work Joined: 29 Sep 20 Online Status: Offline Posts: 497	Post Options Post Reply Quote Grumpycat Report Post Quote Reply Posted: 08 Jan 22 at 12:09pm
	Think your taking this a little to seriously