In the previous issue we visited Cornell University’s wind tunnel to see how wind flows around an asymmetric spinnaker. We learned a lot, of course, especially the importance of being dynamic with our trim, so we went back to the tunnel to explore some key points of symmetric spinnaker flow and trim.
What is heavy air?
For each team this can vary depending on the experience level aboard – but for most teams it is about 20 knots of wind and above – especially in open unprotected water when the seas have a chance to build and are influenced by the current.
A key element of upwind performance is forestay sag – how loose the forestay (or head stay on amasthead rig) is for the given set of wind and sea conditions.
The setup is crucial to boat speed and pointing as it sets up the entry and power of the headsail as well as the effectiveness of both sails as one combined foil.