Lessons Learned on ISL Sails

Welcome to the twenty-first episode of Lessons Learned, the UK Sailmakers podcast hosted by Buttons Padin. In this episode, Buttons is joined by UK Sailmakers’ lead designer, Pat Considine, to break down the effects of headstay sag on sail performance—and to show how our headsails with ISL (Integrated Structural Luff) technology provide a modern solution. They explore what headstay sag is, why it matters for both boat speed and pointing ability, and the traditional methods sailors use to manage it. Pat also highlights the latest onboard equipment that helps control sag. Finally, they dive into how UK Sailmakers’ ISL technology takes performance even further. ISL is now available on new X-Drive and Titanium headsails, as well as Code Zeros. 00:00 Introduction 00:38 Understanding Headstay Sag 01:51 How to Control Sag 04:36 Halyard Tension & Sail Shape 05:08 Integrated Structural Luff Sails 06:05 How to Use ISL Sails 08:15 Boat Considerations 10:00 Determining Load Transfer 12:06 Conclusion Like and subscribe to the UK Sailmakers YouTube channel to be notified when more great content from our channel is uploaded. The Lessons Learned Podcast is also available for streaming on Spotify, Apple Podcasts, and Amazon Music.