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Downwind sails - the difference between the spinnaker and gennaker

In the world of sailing, understanding sail types is crucial to optimizing performance under various wind conditions. Among these, downwind sails play a critical role when the wind is coming from behind.

These sails are specifically designed to maximize speed and efficiency when sailing with the wind, making them indispensable for both casual cruising and competitive racing.

Here is your chance to explore what downwind sails are, their characteristics, and how spinnakers — perhaps the most well-known type of downwind sail — stand out from other options.

Downwind sails come into play when the wind is behind the boat - typically in angles from 120 to 180 degrees, with the aim of setting a large surface area and creating as much propulsion as possible.

Spinnakers

The spinnaker is the traditional downwind sail. These are available in symmetrical and asymmetrical applications - and adding to it, they are also available in different sizes for different conditions.

The symmetrical spinnaker is known for its almost balloon-like shape, being symmetrical down the centerline of the sail. These are best in true downwind conditions when the wind comes directly from behind the boat.

While the symmetrical spinnakers, also labelled S1 to S5, often are designed for specific conditions, the asymmetrical counterpart is a more diverse choice.

Spinnakers

Asymicon

ASSYMETRIC SPINNAKER

Gennaker

The asymmetric spinnaker, also referred to as a gennaker is an all-round asymmetric downwind sail with optimized shape and size to make the sail stable for easy sailing. In light winds you may come up as high as 90 TWA, and apart from that this sail will cover all angles from 120 to 160 TWA in medium conditions. Can be used with a spi-sok for easier handling.

Spi Icon

SYMMETRIC SPINNAKER

All-round spinnaker

The Spinnaker is an all-round spinnaker with optimized shape and size to make the sail stable for easy sailing. In light winds you may come up as high as 110 TWA, and apart from that this spinnaker will cover all angles from 140 and lower in medium conditions. Can be used with a spi-sok for easier handling.

Gennakers

The asymmetric spinnaker on the other hand, is also known under a different name: The gennaker.

In the hunt for an easier-to-handle solution for downwind use - and making it easier was also important for singlehand sailing. The solution? To combine the features of the genoa, which is also asymmetric, and then the proportions of a spinnaker.

In term, you give away a bit of power and performance in exchange for easier handling - and this is the gennaker.

It has a number of advantages - first off it works well even without a spinnaker pole, and secondly, it's easier handling was a gift for the cruisers out there - especially in combination with furling systems.

Code Zero and Code sails

Code Zero

Another development in downwind sail technology is the Code Zero.

Before, there was a gap in sails used in upwind and downwind conditions. And to some extent, there still is.

But the Code Zero was invented to bridge the gap - taking the idea of the gennaker one step further and closing the gap between upwind and downwind sailing.

Unlike the spinnaker, which performs best with wind directly from behind, the Code Zero is optimised for lighter winds and works efficiently at wind angles of around 50 to 90 degrees.

Its flatter shape makes it somewhat similar to an upwind sail but with more power in reaching conditions. It is often used in light air races where the ability to sail close to the wind is crucial while maintaining downwind performance.

Code Zeros often use more robust materials like laminated fabrics to withstand higher loads, as they are designed to perform at tighter wind angles where the forces on the sail are greater.

Code variants - Permanent Hoist and Multipurpose

Multipurposecode

MULTIPURPOSE CODE

A low-budget code sail

The multipurpose code is a low-budget code sail, that however still works in a big variations of wind angles. It is easy to handle as you hoist it furled around a cable sewn into the luff. Unfurl and sail away. The sail is built from woven polyester.

Codepermanenthoist

CODE PERMANENT HOIST

UV protected code sail

The UV-protected Code Permanent hoist is designed to stay up and ready for use all the time. The sail can be hoisted in the harbor and can then be left up all day long, overnight, and even for weeks while on your way. The sail has a high clew for better downwind performance and visibility at sea. The sail is used on an Anti-Torsion cable and the furling system is bottom/up.

 

Code Cruise 53

CODE ZERO CRUISE 53%

Cruising code zero 53 %

Comfort, easy handling, and power. You hoist this sail furled on its own luff Anti-Torsion cable. Un-furl the sail and instantly you power the boat up and make it go. The Cruising code is designed so you can prepare and hoist the sail in the harbor before you head out. When you finish using the sail, you furl it away and return to your mooring and take the sail down. You will be able to use the sail in angles between 70° TWA to 150° TWA depending on the wind speed.

Code Zero

Raceupwind55

CODE RACE UPWIND 55%

Code Race upwind 55 %

The racing Code Zero is the missing link between your up- and downwind sails. It comes in different designs, suited optimally to the rating-/class rules and the rest of your sail inventory. It will be a lightweight sail that is set flying, furled on an anti-torsion cable in the luff which makes it quick to set and retrieve. Produced in the stable EPEX membrane, film on film surface and technora fibers, this sail is designed to work optimally in angles between 50° TWA to 110° TWA depending on the wind speed. Measures in most rules as a headsail.

Cablefreecode 65

CRUISING CABLE-FREE CODE

Cruising cable-free code 65% / rating optimized code

A cable-free code sail is designed with a high-density load bearing fiber luff, that replaces the cable. The Cable-free Code Zero is easy to handle and store. With the improved positive luff, you gain wider sailing angles compared to a traditional Code Zero - and more power. It is also a very stable sail to use if sailing butterfly as well, on the opposite side of the main. This is also a good choice for national racing as it often fits national ratings for keelboats.

Code 65

CODE ZERO 65%

Code Zero 65% - larger cruising code / rating optimized code

The code Zero is the missing link between your up- and downwind sails. It comes in different designs, suited optimally to the rating-/class rules and the rest of your sail inventory. It will be a lightweight sail that is set flying, furled on an anti-torsion cable in the luff which makes it quick to set and retrieve. The sail is designed to work optimally in angles between 70° TWA to 110° TWA depending on the wind speed. This Code 65 with cable is best suited for Multihull use - are you going for a Code 65% for a keelboat, the cable-free version is the better choice.

Cablefreecode 75

RACING CABLE-FREE CODE

Race cable-free code 75 %

A cable-free code sail is designed with a high-density load bearing fiber luff, that replaces the cable. The Cable-free Code Zero is easy to handle and store. With the improved positive luff, you gain wider sailing angles compared to a traditional Code Zero - and more power. Different rating rules demands different girth measurements on the sail. We will advice you to specify the perfect sail for your boat, rating rule and use.