Wednesday, September 30, 2009

Jibe SLOWLY!

I have been windsurfing for 30 years now, although with maybe 15 years of breaks in between). For most of these years, I've been working on my planing jibes - and a lot of other windsurfers I talk to have been working on their jibes for many years, too.

My jibes are finally getting decent; I often plane through, as long as the conditions are what I'm used to. Getting onto the water more often since I met my lovely windsurfing wife certainly has helped, but the biggest contribution to better jibes comes from the 3 ABK camps I have attended in the last 20 months.

One of the things Andy had to tell me again and again was to slow things down. I finally really understood what he meant when I looked at my jibe analysis from yesterday's session. I knew I had done a few jibes that were rather nice, fully planing through on my small board. Here a part of the jibe analysis table from GPS Action Replay:

I had always focused on the first few columns - score, begin speed, and end speed (all in mph). This time, I noticed the duration column: each jibe took about 16-18 seconds. That's slow. I did a dry jibe in the kitchen, talking my way through it from jibe entry to getting fully going again:
"loosen up in the ankles, let the sail pull you into the turn, keep the sail tight, pull it all the way back, look forward, now swing the mast to the other side, open up, step, flip the sail, grab the new side, grab with the other hand, hang low, step back, accelerate"
That's about 15 seconds, spoken without any haste!
I then looked back at the GPS records from this year's camp at Kalmus, when I had convinced Andy do do a couple of jibes with the GPS (not surprisingly, both jibes he did were better than any jibe I did the entire day). Sure enough, the time for each of the two rather beautiful jibes also as about 15 seconds; here's video of the GPS replay:

video
The entire movie is 55 seconds long- two jibes make about 35 seconds (not including the preparation), and 20 seconds in between, before and after. This may not seem that slow when you watch the video - but talked yourself through a dry jibe, and watch the time it takes!

So, as Andy says: slow is fast!

Tracking windsurf sessions

Earlier this year, I started logging my windsurf sessions in a little database. Here's a screen shot of a session record:




You can click on the image to see the full size version, but I'll explain the various parts below.


The top left section contain information about the session - where, which gear I used, wind speed, some data from the GPS, and comments.

In this session, I was going for speed and worked on small board jibes. I managed to set a speed record for the board I was using, as well as a jibe record. The "40%" for the jibe means that the minimum speed was 40% of the entry speed; 40% mean I nicely planed through the jibe, but there was room left for improvement.



In the bottom left section is a screen shot from iWindsurf.com that shows the wind for the day. Great day, except that I waited too long before using the Mistral Screamer, our fastest board. Since my lively wife was having too much fun on the Screamer, it was 5:30 or so before I used it, and the wind had gone down a bit by then, both the averages and the lulls. Had I tried an hour earlier, I probably would have set more records.



The top right section has a screen shot of a speed graph, generated with GPS Action Replay. It gives me a quick overview of how the session was - I was planing nicely most of the time. The dips also show me how my jibes were - mostly dry, with a few good ones in between.

The bottom right shows the tracks for the day. They are color-coded for speed; I set the units to mp/h instead of km/h for this image. The blue arrow in the middle shows my personal speed strip for the day - a shallow area behind a little gras island, where the water was nice and flat.
This was the first time I sailed on this side of PowderPoint bridge in Duxbury, and I really liked it - great for northerl winds, where the bridge creates to much wind shadow on the other side.

Tools Used
Here's a quick overview of what I used here:
  • iWindsurf.com for wind forecasts and graphs
  • Navi GT-31 GPS (my best birthday present ever!)
  • GPS Action Replay Pro to analyze and plot the GPS data
  • FileMaker 10 to create the database (I used FileMaker since I had it on my computer; this could probably be done as easily with Bento or something similar)
  • A MacBook Pro running OS X 10.5
I'm also posting my sessions to gps-speedsurfing.com - keeps me humble after I thought I was soooo fast. But then, most serious posters there use dedicated speed equipment, while I'm usually on a 120l board with padded deck that I had bought for my 12-year old daugther a few years back.