SYMMETRICAL SPINNAKERS
S1 — Light Air Reaching
Formally called a VMG spinnaker, the S1 is optimized for light-air downwind performance when boats make the best progress by sailing closer to the wind around 90° and jibing. Built with flat entry and reduced area for 0–10 knots true wind and apparent wind angles 70–110°.
Why add an S1?
In winds under eight knots true, boats make the best progress downwind with the apparent wind around 90 degrees and then jibing. The S1 is specifically designed for these conditions, built from .5 to .6 oz. high-performance nylon like Airx or Superkote. It features a flat entry for sailing closer to the wind and has reduced area to make it easier to fill in light winds. Perfect for VMG downwind sailing in light air conditions.
Light-Air VMG
Optimized for 0–10 knots
Flat entry and reduced area make the S1 easy to fill in light air, allowing you to sail closer angles and maximize velocity made good downwind.
Matrix Construction
Full radial panel layout
UK’s Matrix layout uses narrow panels, each oriented to align threads with primary load-paths, reducing distortion and creating the strongest sail for its weight.
Performance Materials
Airx or Superkote nylon
Built from .5 to .6 oz. high-performance nylon that resists stretch and distortion, preventing the mid-sail stretch that causes leech problems on close reaches.
Construction & Materials
The heart of faster spinnakers is the construction method. The panel layout UK Sailmakers uses is called Matrix, which is a full radial layout that features narrow panels, each oriented to better align the threads in the cloth with the primary load-paths in the spinnaker. This is the most effective way to reduce distortion and make the strongest sail for its weight.
Every panel is shaped on all four sides in order to create a smooth round sail. For one sail to be so versatile, it needs to hold its shape without distorting. Distortion becomes most obvious when close reaching. Spinnakers made with generic nylon cloth stretch in the middle, causing their leeches to harden or hook; which reduces driving power, creates drag, and increases heeling. The only way to prevent distortion, without using too heavy a fabric, is to use performance nylon spinnaker cloth like those made under the Superkote and Airx names. These materials have the same strength and stretch resistance of one weight heavier standard nylon.
Spinnaker Painting Program
Use this program to create a custom look for your new spinnaker or cruising spinnaker. Click here to go to the Spinnaker Painting Program.
FAQs
What makes the S1 different from other symmetrical spinnakers?
The S1 is specifically designed as a VMG spinnaker for light air conditions (0-10 knots). It features a flat entry for sailing closer angles, reduced area for easier filling, and a mid-girth of 75-90% of foot length, making it ideal for apparent wind angles of 70-110°.
What is Matrix construction and why does it matter?
Matrix is UK Sailmakers’ full radial panel layout using narrow panels oriented to align threads with primary load-paths. This reduces distortion and creates the strongest sail for its weight—critical for maintaining shape when close reaching in light air.
Why use Airx or Superkote nylon instead of standard nylon?
Performance nylon like Airx and Superkote has the same strength and stretch resistance as one weight heavier standard nylon. This prevents mid-sail stretch that causes leeches to harden or hook, which reduces power and increases drag and heeling.
