Please select your home edition
Edition
Predictwind - Iridium

America's Cup- Predictwind - Fresh breeze for Final Day 15

by Richard Gladwell on 25 Sep 2013
The America’s Cup Race Course, framed by the Golden Gate Bridge - today the wind blows from right to left, and the ebbing tide flows from left to right against the windflow. The blue sea that can be seen behind the City to the right, is not ocean but the greater expanse of the San Francisco Bay - which exits through the relatively narrow channel under the Bridge. © Richard Gladwell www.photosport.co.nz

A fresh San Fransisco breeze is expected on Day 15, the Final Day, of the 34th America's Cup, for Wednesday, Race 19 of the 2013 America's Cup. The final race is due to start at 1.15pm on Wednesday, local time.

Towards the bottom of this story we feature Predictwind's course routing optimised for wind and tide on the AC race course, and using an AC72 performance profile. It is included to show that the effect of the tide on the race course and race strategies. See bottom of story for the course variations.

For the official line on how the current factor is determined click here Today the tide is flooding (coming in through the Golden Gate) and will negate the previous advantage that exists with an ebbing tide.

With the final race of the regatta set for its regular start time of 1315hrs the wind feeds produced by Predictwind indicate that winds will be around 15-17kts. The feeds produced by Predictwind are close to agreement on the strength at the race start time, and there is only small build in the breeze over the morning.

Officials will add the strength of the tide to set the new wind limit, which will take it just over 24kts. On the basis of this forecast, the winds will be well under that level.

The forecast does not take account of the influence of fog, which can have several effects on the race course winds.


The above image shows the wind speed and direction 1300hrs with breezes expected to be 15-17kts at the start of Race 19 - these are only average speeds and gusts will be higher. The only issue of concern is the more northerly wind direction in some areas of San Francisco Bay, which could affect the set of the course.


The second image (above) shows a graphic representation of the wind build - confirming the numbers for the prognosis.

The third chart (below) shows the wind expectations for Wednesday. Note that sea conditions described in this chart are based on open water and are not descriptive of an enclosed harbour


The courses optimised by Predictwind for an AC72 show that the optimum course only. The red dotted line shows the Leg 2 course recommended for Race 19. The mark positions used in this projection are only very approximate - and will vary on the course set for the day.

In the second course projection, for Leg 3 the tide is expected to be in flood (incoming) for this race, and boats will need to avoid its effects upwind by taking the city shore.




Two weather feeds are used by Predictwind, the key to the accuracy of the forecast lies with the graphs, as when the two lines for the two feeds are quite close together and following each other in the trend, then the likelihood of the forecast is high. If there is separation to any marked degree, then there still some issues to be resolved but usually 24 hours from the race they are well aligned.

The Predictwind model takes various weather feeds and then polishes these, part of this process is factoring in the effect of local topography on the breeze - well demonstrated by the images with the funneling of the breeze.

Developed by former Olympian, Jon Bilger (470, 1992), www.predictwind.com!PredictWind application was used by the Swiss team Alinghi to win the 2003 and 2007 America's Cups, and has become the leading wind system used by racing and recreational sailors around the world. It is available on a subscription basis and also with a free forecast option.

A mobile app for Android and iPhone is available and www.predictwind.com!PredictWind is probably the most used app on the Sail-World iPhone.

Real time local wind observations have been added as further functionality.

You can check the weather anywhere in the world, and get a five day forecast, plus a variety of other features and functions of www.predictwind.com!PredictWind. The app is synchronised with your PC, so that your latest set of locations are always available without resetting each time you change a device.

PredictWind.com 2014Predictwind - IridiumPredictWind.com

Related Articles

The Great Dane dies at 88 + Video
One of the heroes of sailing, Paul Elvstrøm (DEN) has died at the age of 88 years. One of the heroes of sailing, Paul Elvstrøm (DEN) has died at the age of 88 years. Known as the Great Dane, and winner of four Olympic Gold Medals, and many world championships in multiple classes from dinghies to keelboats, Elvstrøm put a footprint on the sport like no other.
Posted on 7 Dec
A Q&A with Olympic champ Malcolm Page about his new job at US Sailing
I recently talked with Malcolm Page, US Sailing’s newly hired Chief of Olympic Sailing, to learn more about his new job. Malcolm Page (AUS; 44) is a hyper-talented Men’s 470 sailor who won two Olympic gold medals (2008 and 2012) sailing with two different skippers, as well as seven World Championship titles, and who has long studied under the legendary Ukrainian coach Victor Kovalenko. I recently talked with Page, who was just hired as US Sailing’s new Chief of Olympic Sailing, to learn more about his new job.
Posted on 5 Dec
America's Cup - Kiwi lodges Appeal against Jury in San Francisco Cup
Former Oracle Team USA crew member, Matthew Mitchell (NZL) has lodged an Appeal against a Decision to dismiss his case Former Oracle Team USA crew member, Matthew Mitchell (NZL) has lodged an Appeal against a Decision to dismiss his case taken against the International Jury for the 34th America's Cup in San Francisco. On October 28, 2016, US District Judge Vince Chhabria dismissed Mitchell's claim against the five-person International Jury on the basis that it was lodged too late.
Posted on 2 Dec
A Q&A with Nick Bice about the recent changes for the 2017/2018 VOR
I caught up with Nick Bice, the VOR’s director of boats and maintenance, to learn more about the VOR’s new directions. I recently had the pleasure of hearing Nick Bice, the Volvo Ocean Race’s director of boats and maintenance, deliver a keynote speech to an audience of marine-industry professionals and official Volvo Ocean Race suppliers at the 2016 METS trade show in Amsterdam. I caught up with Bice after his presentation to learn more about the new directions that the race is taking for its thirteenth edition.
Posted on 28 Nov
A Q&A with Sharon Green about the prep work that ensures great images
I talked with ace photographer Sharon Green to learn more about the prep work that goes into each image that she snaps. I caught up with ace photographer Sharon Green at the 2016 Alcatel J/70 Worlds to learn more about the behind-the-scenes preparation work that goes into each image that she snaps. While some of Green’s tips are specific to professional shooters (e.g., helicopter time or juggling multiple camera bodies), plenty of amateur lensmen will be well served to consider Green’s racecourse-proven tips.
Posted on 23 Nov
Dockside with CQS - radical, revamped supermaxi up close
The revamped supermaxi CQS is currently in Auckland's Silo Marina, ahead of her first race on Friday The revamped supermaxi CQS is currently in Auckland's Silo Marina, ahead of her first race on Friday - the White Island Race which will double as Rolex Sydney Hobart Qualifier. Originally the 90ft Nicorette designed by South African Alex Simonis, the new project to upgrade to a 100ft supermaxi has been led by Brett Bakewell-White (NZ) and Bakewell-White Yacht Design.
Posted on 22 Nov
Gladwell's Line - President Croce caught at helm in Perfect Storm
No real surprise that incumbent President Carlo Croce (ITA) was unseated mid-way an eight-year term After a year or more punctuated with issues that should not have happened, it is no real surprise that incumbent President Carlo Croce (ITA) was unseated mid-way through what should have been an eight-year term. Also gone is one of his lieutenants, Chris Atkins (GBR) as Vice President, who remarkably polled 13th out of the 15 candidates.
Posted on 15 Nov
Gladwell's Line -The America's Cup settlement deal
The 'News' today that Emirates Team New Zealand has won their case before the Arbitration Panel is not news The 'News' today that Emirates Team New Zealand has won their case before the America's Cup Arbitration Panel is not new - Sail-World reported the same story in the first and second weeks of September. The Hearing on the amount of compensation to be paid is yet to be held. So far we have been unable to discover a date if indeed one has been set. Maybe next year?
Posted on 11 Oct
Debriefing the 2016 J/70 Worlds with Winning Skipper Joel Ronning
I talked with Joel Ronning after the 2016 Alcatel J/70 Worlds to learn about his team’s win at this high-level regatta. Since its inception in 2012, the J/70 has become the most popular One Design boat in decades, with 1,100+ boats sailing in myriad countries. Some 68 boats from 15 countries arrived on San Francisco Bay last week to determine bragging rights at the 2016 Alcatel J/70 Worlds. I caught up with Joel Ronning to learn more about the Catapult team’s road to becoming the 2016 J/70 World Champions.
Posted on 5 Oct
Rio 2016 - America's Cup champ says Paralympic racing is closest ever
Twice America’s Cup champion, Rick Dodson is extremely impressed with the standard of racing in the three man Sonar Twice America’s Cup champion, Rick Dodson is extremely impressed with the standard of racing in the three man Sonar keelboat class at the 2016 Paralympics in Rio de Janeiro. The regatta is being held in Guanabara Bay on three of the courses used for the Olympic Sailing Regatta in August.
Posted on 13 Sep