ASYMMETRICAL SPINNAKERS
A2 Light Air Running — The Go-To Sail
The most versatile sail in your inventory. Designed for apparent wind angles 105–155° and 8–18 knots, featuring full-sized construction with a full entry and high clew that rotates windward of the forestay for maximum projection out of the mainsail’s shadow.
Why the A2 is Your Go-To Sail
The A2 is the go-to sail on most boats. Sprit boats never run dead downwind because the asymmetrical spinnaker gets blanketed behind the mainsail if they sail below 155 degrees TWA. For an asymmetric spinnaker flown off of a centerline pole, “running” is when the boat sails with the apparent wind angle greater than 90 degrees until the boat is sailing as deep as 155 degrees AWA. An A2 (light/medium runner) is used in apparent wind speeds of 8-18 knots.
To help sail as low as possible, UK Sailmakers designs these sails to be full-sized with a full entry and a high clew so that the middle of the sail will flatten out and rotate to windward of the headstay to get as much of the sail as possible out of the wind shadow of the mainsail.
Maximum Versatility
105-155° apparent wind angles
The A2 covers the broadest range of running angles in 8-18 knots, making it the most-used sail in your asymmetrical inventory for typical racing and cruising conditions.
Optimized Geometry
Full entry & high clew design
Full-sized construction with strategic shaping allows the sail to flatten and rotate windward of the forestay, projecting maximum area out of the mainsail’s wind shadow.
Matrix Construction
Radial panel layout
UK’s Matrix construction features narrow panels oriented to align cloth threads with primary loadpaths, creating the strongest sail for its weight while minimizing distortion.
Understanding Matrix Construction
The key to faster spinnakers lies in their construction. UK Sailmakers uses a Matrix panel layout—a radial design made up of narrow panels aligned with the sail’s primary load paths. Panels radiate from the head, tack, and clew, joined by vertical Matrix panels through the midsection. This layout minimizes distortion and delivers the strongest, most efficient sail for its weight.
Each panel is shaped on all sides to create a smooth, round sail. For one sail to be so versatile, a spinnaker must hold its designed shape without distortion. Distortion is most noticeable when close reaching. Spinnakers made from generic nylon tend to stretch through the middle, which causes the leeches to harden or hook. This reduces driving power, increases drag, and adds heel. The most effective way to prevent distortion, without using a heavier fabric, is to build the sail from performance nylon spinnaker cloth. These materials provide the strength and stretch resistance of standard nylon that is one weight heavier.
A2 in Action
FAQs
Why is the A2 called the “go-to sail”?
The A2 covers the widest range of practical running angles (105-155° AWA) in the most common wind speeds (8-18 knots). It’s the sail you’ll use most often on asymmetrical boats, making it the workhorse of your spinnaker inventory.
What’s the difference between the A2 and deeper running sails?
The A2 has a mid-girth of 100-105% of the foot length, making it fuller than an A1 but optimized for moderate running angles. It features a full entry and high clew that allows it to rotate windward of the forestay to escape the mainsail’s wind shadow.
Why can’t I sail dead downwind with an asymmetrical spinnaker?
Sprit boats get blanketed by the mainsail below 155° TWA. The A2’s design with its ability to rotate forward of the forestay helps you sail as deep as possible (up to 155° AWA) while keeping the sail in clean air.
What makes Matrix construction better than traditional methods?
Matrix uses narrow, fully-shaped panels oriented to align threads with primary loadpaths, minimizing distortion especially when close reaching. Combined with high-performance Superkote or Airx nylon, it creates the strongest sail for its weight.
