Rob, a sailor from Auckland, shares his experiences racing on the Waitemata Harbour while discussing the importance of understanding tides, wind conditions, and strategic decision-making in sailing. He proposes creating an interactive open data map to help sailors leverage these factors for better performance. The goal is to enhance sailing skills and improve chances of winning races.

1. http://www.flickr .com/photos/joriel/3230590513
Curtailing Crustaceans
with Geeky Enthusiasm
Rob Coup
robert.coup@koordinates.com
@amatix
1
G’day folks, my name is Rob! And I’m here to talk about sailing.

2. Me
Auckland
2
I live in a beautiful city a wee-way north of here, and spend a hunk of my time out sailing on
the Waitemata Harbour and in the Hauraki Gulf. You really can’t beat it :)

3. Me
3
We do a bit of racing, maybe once or twice a week. For those who care, the boat is a Farr
1020 which is about 33 feet long, and was built in the glorious eighties. We mostly sail with
the Ponsonby Cruising Club who are based down near the harbour bridge.

4. Me
4
Our crew is young and beautiful, but we work hard and don’t have a lot of spare time. We
certainly can’t be out on the harbour every afternoon.

5. http://www.flickr .com/photos/stebbix/128396769
Barnacles
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However, the old barnacles who race against us do spend every afternoon of every day
racing. They got past ten thousand hours a few years back…

6. http://www.flickr .com/photos/cocoamademoiselle/4422776787
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And when they’re not out on a boat, they’re in the pub talking about being out on a boat.

7. Me
behind - bad
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We do okay, but there’s a bit too much of this

8. Me
in f ront - =good
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And not enough of this!

9. http://www.flickr .com/photos/dave_apple/159908561
Bruce
Farr cup
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We want to win more prizes. In sailing, prizes invariably means bar-tabs or alcohol. Yay!

10. http://www.flickr .com/photos/ittybittiesforyou/4667430094
Tricks of the course
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What makes a win? A faster boat helps, but handicaps cancel that out. We’re not too shabby
at our skills either. But the real key is learning the tricks of the harbour. Apparently that
comes from something called “experience”. So what are these tricks?

11. http://www.flickr .com/photos/tomorrowstand/4310087252
Tides
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Tides and currents make a big difference. Getting sucked backwards is suboptimal. Getting
pushed forwards while others are being sucked back? Classic.

12. Me
Out? In?
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Tides head in different directions in different places at different times. Should you stay out
here, or sneak right alongside that Navy ship like a would-be terrorist?

13. http://www.flickr .com/photos/good_day/with/61220319/
Wind
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Wind makes quite a big difference too, as you might imagine...

14. Me
How big is the shadow?
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Every hill, building, and wharf casts a wind shadow and has funny winds swirling around it
and funneling nearby. If those funny winds are helping you - awesome. If they’re stopping
you from getting where you want to go? Not so good. And of course, it all depends on the
direction and strength of the wind at any particular moment.

15. Me
Follow the leader? Zzzz...
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You’re never going to win if you just follow the boat in front of you. Well, you can always
hope that they catastrophically screw up. You really need to do something and go somewhere
different. But what? where? and when is the right time to make your move?

16. http://www.flickr .com/photos/stebbix/128396769
Evil Captain Barnacle
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Remember evil captain Barnacle?

17. http://www.flickr .com/photos/chebbs/164258862
Secret Maps!
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Apparently him & his evil pirate mates have a secret hand-drawn map of the harbour with all
the tricks on! Can you believe it? Might look a bit like this if it was drawn on concrete. Only
with sailing stuff instead of monkeys. Yeah. Umm. So….

18. http://www.flickr .com/photos/cassidy/417821894
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What is the big idea? The big idea is to use some open data, mash it together, and come up
with our own interactive secret map. Only it wouldn’t be secret. That way we skip this whole
“experience” thing and get back to competing on our skills. As a bonus, someone could take
it, add their own data, and use it anywhere else in the world.

19. http://www.flickr .com/photos/stebbix/128396769
Barnacle McTechnophobe
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Plus, do you think Evil Captain Barnacle is going to be using the latest technology? Doubt it.

20. www.linz.govt.nz
Maps
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We’ll need some maps. LINZ can help us with those - thanks!.

21. Me
Wind History
Time Speed Direction
12:30pm 12.2 kn 277°
12:35pm 13.1 kn 279°
12:40pm 12.7 kn 274°
12:45pm 12.3 kn 270°
12:50pm 11.0 kn 276°
12:55pm 12.1 kn 277°
1:00pm 13.6 kn 283°
1:05pm 13.1 kn 285°
1:10pm 13.3 kn 286°
1:15pm 12.9 kn 289°
21
We’ll also need to know what the wind has been like in the past, and how it changes in
different places around the harbour. NIWA, Coastguard, and the yacht clubs should be able to
help us here.

22. http://www.swanagesailingclub.org.uk/clubhouse/tidestream/tidalstream.htm
Tidal Flows
22
The port has nifty and accurate data showing how the tide changes around the harbour. As
the tides go in and out the little arrows go in lots of odd directions. They also have really
accurate data on where the shallow and deep bits start and finish. Apparently they use all this
to stop big ships crashing into wharves or something...

23. http://www.flickr .com/photos/leokan/3656810914
Tide times
Time Height
3:54am 2.9 m
9:58am 0.7 m
4:23pm 3.0 m
10:33pm 0.6 m
4:59am 3.0 m
11:02am 0.6 m
6:21pm 3.2 m
12:30am 0.4 m
7:00am 3.2 m
12:58pm 0.4 m
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We’ll also need to know when the tides are, and how big they are going to be. Again, LINZ
can help us with this.

24. http://www.flickr .com/photos/prizepony/2619415688
Where
am I?
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So, if we can combine all that with where we are right now

25. http://www.flickr .com/photos/dbarefoot/15406232/
Wind right now
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And what the wind is like right now

26. http://www.flickr .com/photos/35064820@N00/3950391591/
Maths
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And a bit of maths. And by maths I really mean software, but I liked this picture better.

27. http://www.flickr .com/photos/jaredearle/4675262184/
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We’ll also need some funky gadget to display the current winds and tide flows on, and see
what they’re predicted to be 15-30 minutes into the future. This will allow us to make better
decisions about where to go.

28. Me
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And better decisions means we end up in front more often!

29. http://www.flickr .com/photos/clevercupcakes/3019749158
Victory!
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And then we win!

30. http://www.flickr .com/photos/dotstreats/1557180394
robert.coup@koordinates.com
@amatix
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And the crew rejoice! If you want to help out with this idea, come out sailing with us, or learn
more, feel free to get in touch. Thank you!