09/03/2015
Technology for a dinghy sailor from mysailor.com.au
11 Oct 2012
We have been sailing and racing dinghies for a long time with some successes over the years. But as we have been brought up in the technology era working with computers, we have always tried to maximise our use of technology to help improve our performances. In the last few years we have seen things such as handheld GPS’s, GoPro cameras and smart phones really expand where technology can help the dinghy sailor.
The following is a list of examples of how we have used some of this technology, which we hope is of value to people who like to race dinghies.
Examples of how we have used technology
1. In boats where the mast is supported by spreaders - it is extremely important to ensure the spreaders are just the right length. What you are after is a mast that does not bend sideways until you are starting to de-power. If it bends too early, then you will never get your maximum power for your weight, and if it bends too late, you will need to work harder than the boats around you to keep the boat on its feet. The way we analysed our mast was to attach a GoPro camera to the deck of the boat facing directly up the mast and filmed how the rig was working through a range of wind conditions. Doing this we were quickly able to determine the correct spreader lengths.
2. One of the arts of sailing downwind is to determine the fastest angle to the wind, ie do you sail low and slow, or high and fast. This is different for each class and will change as wind and wave height changes. In our fireball there is a critical wind wave combination that has a major impact on which angle to sail. When you get onto the run, it is imperative that you pick that angle correctly otherwise you can go from hero to zero very quickly. We used a GPS to try and determine the conditions for when the cutover happens. The approach we used was to set a waypoint as far downwind as the GPS would allow (ours was 9,999 km). Then all you had to do was monitor the VMG (Velocity Made Good) to that waypoint. Some of the later sailing specific GPS’s have in built functions reducing the steps to get the VMG set up. This same technique can be used upwind as well, by setting the waypoint dead upwind, but we found it difficult as the improvements were minor and minor changes in wind had a bigger impact.
3. This year we have been sailing the Tasar a lot and discovered that our tacking in lighter conditions was not as good as some of our competitors. Being the techies we are, we built an iPhone application that records video, GPS speed, angle of heel, and true compass direction to try and determine what the optimum approach to tacking was. Using a LifeProof water proof case we attached the phone to the boat and monitored our movements and the boats performance. This was invaluable for us to “reinvent” the way were tacking and helped us to have more confidence in our racing. We have now released this Video Proof on the Apple App store.
4. Recently we did a regatta at Darwin, and as anyone who has sailed there will know, it has a strong tide, which can be tricky at times. We “discovered” what most yacht sailors would know is the Navionics iPhone application which was fantastic at showing us where we were sailing and what the water flow and relative depths were. We did however find it was a little “macro” for dinghy sailing and didn’t always provide the fine detail that we needed. We were also aware that the only way we could really determine the currents was do what the Olympic coaches do and put GPS’s on tide sticks all around the location and track their progress. We unfortunately didn’t have the resources for that, so we again turned to our techie back ground and wrote an iPhone app that would do something similar.
The application works by fixing a waypoint using the GPS of the iPhone at the same time as dropping a tide stick in the water. You then pick the stick up a couple of minutes later and fix a second waypoint (nb we always kept the iPhone on the boat and not in the water with the tide stick. The application then calculates the speed and direction of the tide stick and places the information onto a map along with a timestamp so you can compare it to the tide times. By doing enough of those around the course area we went into the regatta with confidence about what was happening under the water. Tidestick is also available at the App Store.
5. One of the things that has always been important to me is understanding how much wind there is now and what the wind is going to do. Living in Melbourne the Bureau of Meteorology has some great locations that they observe the current wind from. These include Fawkner Beacon, South Channel Island, Point Wilson and Melbourne Airport. These locations usually provide ample warning if the conditions are going to change. As much as I like wind forecasts and will continually check forecast information at the web sites such as Seabreeze, PredictWind and the Bureau themselves, I am addicted to current conditions as this is reality. We have been lucky to have web sites such as BayWX that quickly map out the conditions and provide historic graphs. But of course being a techie I wanted something that would work easily on my phone without having to type in urls and pull all the data together. From this desire came MelbWinds, and as I travelled around for regattas the application has been cloned for each capital city in Australia, the US and the South Coast of the UK. The application has been designed so that I can display all the local wind locations where the wind is above a specified amount, and do a regular poll to quickly see if the conditions are about to deteriorate. This great for when we are out training by ourselves and is also great for race management to try and stay a step ahead of the conditions.
6. Other things I like to do is analyse races to determine, what was the major contributor to our success or failure. Unfortunately we usually seem to be analysing the later. The best way I have found for this is GPS tracking. In the past however we only ever had a GPS on our own boat, and found the information was very limited. Nowadays with technology such as TackTracker it is very easy to determine what is the one thing or the mistake that is holding you back. This is also evolving into a fantastic resource to allow people to “watch” yacht/dinghy racing live anywhere in the world. The 505 class are probably the leader with using this type of technology, and more recently the 49er class used this technology Europeans.
- Chris Payne
