Login
Support Sailonline
If you haven't already - join the SAILONLINE YACHT CLUB!
Please also consider making a donation - all amounts are greatly appreciated!
Posted by kroppyer ![]() |
|
warning: I'll explain how serverjumps, commands and the client refresh rate work, but it's complicated and I cannot tell you yet how to take advantage of this knowledge (when rounding a mark for example)
Most of you know about server jumps. For rounding a mark, it's important to turn as early as possible, but absolutely not too early. This is made difficult by the server jumps, and client refresh rate, you rarely see your boat where it actually is. What you see is running a couple of seconds behind, in rare cases it could reach up to about 45 seconds. So what is exactly happening. It's more than just the server jumps and the client update rate, but let's start with them anyway: The server continuously checks all boats. For every boat that has not been moved by the server for at least 10 seconds, the server updates its position. This means, your boat will move every 10-12 seconds (when it's busy, it may take 2 seconds before the server notices it hasn't moved your boat yet). When you haven't issued a command in the last 15 minutes or so, the server may skip you once or twice, and then do one big jump to catch up. This unloads the server a bit from boats that aren't actively steered. useful tip: send a command 5-10 minutes before rounding a mark (setting a delayed command for 5-10 minutes before the mark also works). It'll make sure the server jumps for your boat are short when you reach the mark. For the rest of this post, let's assume server jumps of 11 seconds: your boat is moved by the server every 11 seconds. I'm also assuming you have a fast internet connection. The client polls the server every 15 seconds (roughly). Let's see what can happen with an example: 12:00:00 (jump) server moves your boat 12:00:00 (poll) client polls boat position, you see your boat at its current position (barely any delay!) 12:00:11 (jump) 12:00:15 (poll) your boat moves from its 12:00:00 position to its 12:00:11 position (running 4 second behind) 12:00:22 (jump) 12:00:30 (poll) your boat moves from its 12:00:11 position (19 seconds behind) to its 12:00:22 position (8 seconds behind). 12:00:33 (jump) 12:00:44 (jump) 12:00:45 (poll) your boat moves from its 12:00:22 position (23 seconds behind) to its 12:00:44 position (1 second behind). Note: the 12:00:33 position is not shown, it looks like you made one large jump. A better understanding of how this works may not easily transfer into being able to steer your boat better. One useful tip is: when you see your boat make a large jump, you know two server jumps happened in the last 15 seconds, meaning the last jump happened less then 4 seconds ago. If you see a short jump, you know only 1 server jump happened in the last 15 seconds, meaning the last jump happened between 4 and 11 seconds ago. Commands are executed independently from serverjumps. What does this mean? You might have seen your command execute at the start of a new server jump, or at the end. Both can happen. A command will never execute in the middle of a serverjump. All commands due to be executed (of every boat, in every race) are executed in one go, with 4 or 5 seconds between each go. So your command will generally be executed within 5 seconds after the time you set the command for. BUT your boat may still be at a position from 11 seconds ago. This means, your command will have an effect 11 seconds earlier than it was set to execute. So now there are three things with an interval: the client polls ever 15 seconds, the server moves boats every 11 seconds and turns boats every 4 or 5 seconds. This is complicated, I can't tell you yet how to take advantage of this knowledge. Up to now I've done one of two things for markroundings: - wait until the client shows me clear to round, then send the command. - when I expect a double jump to happen until the next client refresh, and I only need one more jump, I count, to 10. But 11 is probably safer. Now I've researched how commands work, I might come up with a method that results in better roundings, without the risk of missing the mark. That will be something I'll post on solfans |
|
Posted by JimKnopf ![]() |
|
One advantage I take of your very informative explanation is: Don’t tack (gybe) too short for rounding a waypoint/buoy. To set a tack command in advance may have the effect to round too early. Seems to be better to wait for the visible pass by of the waypoint – then tack or gybe or set new course.
(Apologies for bad english). |
|
Posted by Kipper1258 ![]() |
|
This is why roundings are missed even though DC Checker shows the mark as clear. DC Checker assumes that the DC is going to fire exactly at that time with no uncertainty. That is not the case in reality.
|
Please login to post a reply.
Races
Next Race: 00d 00h 00m
Current Races:
Galveston to Galway 2022
For the second time, we will be able to test our navigational skills in this massive ocean race across the Gulf of Mexico and the Atlantic Ocean! You can navigate the 4980 NM to Galway, Ireland in any direction, of course within the designated race boundary area. Your only task is to reach the finish line in the best place, preferably at the highest podium. Prepare your C2R 74 well for the race and take advantage of all its opportunities. Good luck!
PRIZE: SMPF
Race #1592
INFO by brainaid.de
C2R 74 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking:
OCQ3 - OCCH - SUPSOL - SYC
Race starts: Jul 09th 18:00
Registration Open!
Sines to Bermuda 2022
Another race with the finish line in Bermuda. This time we will start from Sines in Portugal. There is 3213nm ahead of us across the Atlantic Ocean. Previously, this race was one of the stages of the Rendez-Vous 2017 Tall Ships Regatta. This time we will use this route in the race played as part of the SOL All Round Championships and we will use our Orange 125 fast catamarans to cover it. We invite you to participate.
Race #1591
INFO by brainaid.de
Orange 125 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking:
ARQ3 - ARCH - SUPSOL - SYC
Race starts: Jul 04th 04:00
Registration Open!
PIC Insurance 2022 - Race 1
Welcome to Auckland, New Zealand! Sailonline is happy to provide our SOLers with the virtual version of the brilliant three-race SSANZ two-handed series which will be sponsored by PIC Insurance Brokers this year. We will be racing around the beautiful waters of the Hauraki Gulf off New Zealand’s North Island. Our first race of the Series is a 50-miler out to Motuora Island and back. Our direct competitors as always in our Young 88s will be the real racers of the Young 88 Association who will be participating in the Railblaza fleet in the real life race!
Race #1598
INFO by brainaid.de
Young 88 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: SPRCH - SPRQ3 - SUPERSOL - SSANZ - SYC
RACE CLOSE: Wednesday,
July 6 at 2300 UTC.
Race starts: Jul 01st 21:15
Registration Closed
Geraldton to Cape Town 2022
A race in the Southern Indian Ocean is always entertaining, especially in a Riptide 50. Traditionally the course would be West to East, to take advantage of the prevailing winds, but this time the SRC is challenging us to an E-W course, from Geraldton in Western Australia to Cape Town in South Africa. A brief 4800nm!
PRIZE: SMPF
Race #1575
INFO by brainaid.de
Riptide 50 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking:
OCQ2 - OCCH - SUPSOL - SYC
RACE CLOSE: Thursday,
July 14 at 2300 UTC.
Race starts: Jun 12th 05:00
Registration Closed
SYC Ranking
Series
- SYC ranking
- 2022 TRQ4
- 2022 TRQ3
- 2022 TRQ2
- 2022 TRQ1
- 2022 TRCH
- 2022 Tall Ships
- 2022 SUPerSOLer
- 2022 SSANZ
- 2022 SSA
- 2022 SPRQ4
- 2022 SPRQ3
- 2022 SPRQ2
- 2022 SPRQ1
- 2022 SPRCH
- 2022 SHE
- 2022 OCQ4
- 2022 OCQ3
- 2022 OCQ2
- 2022 OCQ1
- 2022 OCCH
- 2022 NTR
- 2022 LOOR
- 2022 CTR
- 2022 ARQ4
- 2022 ARQ3
- 2022 ARQ2
- 2022 ARQ1
- 2022 ARCH
- 2021 TRQ4
- 2021 TRQ3
- 2021 TRQ2
- 2021 TRQ1
- 2021 TRCH
- 2021 TD
- 2021 Tall Ships
- 2021 SYCQ4
- 2021 SYCQ3
- 2021 SYCQ2
- 2021 SYCQ1
- 2021 SYCCH
- 2021 SUPerSOLer
- 2021 SSANZ
- 2021 SPRQ4
- 2021 SPRQ3
- 2021 SPRQ2
- 2021 SPRQ1
- 2021 SPRCH
- 2021 Shetland
- 2021 PAC6
- 2021 OCQ4
- 2021 OCQ3
- 2021 OCQ2
- 2021 OCQ1
- 2021 OCCH
- 2021 ESRW
- 2020 TSE
- 2020 TSA
- 2020 TRQ4
- 2020 TRQ4
- 2020 TRQ3
- 2020 TRQ2
- 2020 TRQ1
- 2020 TRCH
- 2020 Tasman Double
- 2020 SYCQ4
- 2020 SYCQ3
- 2020 SYCQ2
- 2020 SYCQ1
- 2020 SYCCH
- 2020 SUPerSOLer
- 2020 SSANZ
- 2020 SRQ4
- 2020 SRQ3
- 2020 SRQ2
- 2020 SRQ1
- 2020 SPRCH
- 2020 Shetland
- 2020 RTW
- 2020 RNI
- 2020 Odyssey
- 2020 OCQ4
- 2020 OCQ3
- 2020 OCQ2
- 2020 OCQ1
- 2020 OCCH
- 2020 A3
- 2019 TRQ4
- 2019 TRQ3
- 2019 TRQ2
- 2019 TRQ1
- 2019 TRCH
- 2019 Tasman Double
- 2019 Tall Ships
- 2019 SYCQ4
- 2019 SYCQ3
- 2019 SYCQ2
- 2019 SYCQ1
- 2019 SYCCH
- 2019 SUPerSOLer
- 2019 SSANZ
- 2019 SRQ4
- 2019 SRQ3
- 2019 SRQ2
- 2019 SRQ1
- 2019 SPRCH
- 2019 Shetland
- 2019 Round New Zealand
- 2019 OCQ4
- 2019 OCQ3
- 2019 OCQ2
- 2019 OCQ1
- 2019 OCCH
- 2018 TRQ4
- 2018 TRQ3
- 2018 TRQ2
- 2018 TRQ1
- 2018 TRCH
- 2018 Tasman Double
- 2018 Tall Ships
- 2018 SUPSOL
- 2018 SSANZ Triple
- 2018 SRQ4
- 2018 SRQ3
- 2018 SRQ2
- 2018 SRQ1
- 2018 SPRCH
- 2018 Shetland
- 2018 Shackleton Challenge
- 2018 OCQ4
- 2018 OCQ3
- 2018 OCQ2
- 2018 OCQ1
- 2018 OCCH
- 2018 40CH
- 2017 TS RDV
- 2017 TRQ4
- 2017 TRQ3
- 2017 TRQ2
- 2017 TRQ1
- 2017 TRCH
- 2017 Tasman Double
- 2017 Tall Ships
- 2017 SWR
- 2017 SUPSOL
- 2017 SSANZ Triple
- 2017 SSANZ RNI
- 2017 SPRR3
- 2017 SPRR2
- 2017 SPRR1
- 2017 SPRCH
- 2017 Red Dot
- 2017 OCQ4
- 2017 OCQ3
- 2017 OCQ2
- 2017 OCQ1
- 2017 OCCH
- 2017 40CQ3&4
- 2017 40CQ1&2
- 2016 TRQ4
- 2016 TRQ3
- 2016 TRQ2
- 2016 TRQ1
- 2016 TRCH
- 2016 Tasman Double
- 2016 Tall Ships
- 2016 SUPSOL
- 2016 SSANZ Triple
- 2016 SRQ4
- 2016 SRQ3
- 2016 SRQ2
- 2016 SRQ1
- 2016 SPRCH
- 2016 RTWR
- 2016 OCQ4
- 2016 OCQ3
- 2016 OCQ2
- 2016 OCQ1
- 2016 OCCH
- 2016 Corporate Open Gold
- 2016 A3
- 2015 TRQ4
- 2015 TRQ3
- 2015 TRQ2
- 2015 TRQ1
- 2015 TRCH
- 2015 Tasman Double
- 2015 Tall Ships
- 2015 SYQ4
- 2015 SYQ3
- 2015 SYQ2
- 2015 SYQ1
- 2015 SYCCH
- 2015 SUPSOL
- 2015 SSANZ Triple
- 2015 SRQ4
- 2015 SRQ3
- 2015 SRQ2
- 2015 SRQ1
- 2015 SPRCH
- 2015 OCQ4
- 2015 OCQ3
- 2015 OCQ2
- 2015 OCQ1
- 2015 OCCH
- 2015 Aegean Rally
- 2014 Timed Races Championship
- 2014 Tasman Double
- 2014 Tall Ships
- 2014 SYC Championship
- 2014 SSANZ Trio
- 2014 SSANZ RNI
- 2014 Sprints Championship
- 2014 Scandinavian Tour
- 2014 Round The World Race
- 2014 Ocean Championship
- 2014-2015 Sailonline World Race
- 2013 Tall Ships
- 2013 SYC Championship
- 2013 SSANZ B&G Simrad
- 2013 Capt Anderson
- 2012 W Australia Regatta
- 2012 Tall Ships
- 2012 SSANZ B&G Simrad
- 2012 RNZ Two Handed
- 2012 Global Challenge
- 2012 Ecker Cup
- 2012 Black Sea
- 2012 A3
- 2011 Vancouver Island
- 2011 Tasman Double
- 2011 SSANZ B&G Simrad
- 2011 SOL Global Challenge
- 2011 SJORA Series
- 2011 Scandinavian Tour
- 2011 Round North Island
- 2011 Asian Sprints
- 2011-2012 SOL World Race
- 2010 Tasman Double
- 2010 Ouzo Rally
- 2010 Iberian Tour
- 2010 Auckland Regional
- 2009 French SOLo
- 2009 Bosphore - Bretagne
- 2008 SYCC
- 2008 -2013 SYC Week Race Championship
- 2008 -2013 SYC Week-End Race Championship
- 2008 -2013 SYC Ocean Race Championship
- 2008-2009 Sailonline Ocean Race
Mobile Client
SYC members have the benefit of access to our mobile/lightweight web client!