Introduction
Bluewater cruising often evokes romantic images of sailing bareheaded before the trade winds for days on end. However, the reality of downwind sailing on a large catamaran can sometimes be frustrating if you do not have the right sail inventory.
Because catamarans do not heel and have a large wetted surface area, they can easily outrun their apparent wind when sailing deep angles. The apparent wind drops, the heavy Dacron mainsail begins to flog in the rolling swell, and the boat slows to a crawl. To keep a multihull moving efficiently off the wind, you need specialized, lightweight, high-powered sails. At Kraken Sails, we consider a dedicated downwind sail an absolute necessity for offshore cruising. In this post, we will compare the two primary weapons in the downwind arsenal: the Code Zero and the Asymmetrical Spinnaker.
The Versatile Workhorse: The Code Zero
A Code Zero is essentially a massive, very flat-cut asymmetrical spinnaker or a very full, lightweight genoa. It is designed to be flown free-flying (unattached to the forestay) from a bowsprit, using a continuous line furler.
How it Works
The luff of a Code Zero contains an anti-torsion cable (usually made of Kevlar or Dyneema). This cable allows the sail to be rolled up tightly around itself, much like a window blind, using a continuous line furler operated from the safety of the cockpit.
When to Use It
The Code Zero is the ultimate “reaching” sail. It excels when the apparent wind angle is between 60 degrees and 120 degrees. In light air (5 to 12 knots), a Code Zero provides a massive boost in horsepower, allowing a heavy catamaran to sail at wind speed or faster. It is often the difference between enjoying a beautiful sail and having to turn on the noisy diesel engines.
Because it is relatively flat, a Code Zero can even be used effectively to sail upwind in very light conditions, pointing almost as high as a standard genoa but with significantly more power.
The Verdict for Cruisers
If your budget only allows for one specialized off-wind sail, make it a Code Zero. It is incredibly versatile, easy to deploy and furl short-handed, and covers the wind angles where cruising catamarans most often struggle.
The Deep Downwind Specialist: The Asymmetrical Spinnaker
While a Code Zero is fantastic for reaching, it is too flat to project effectively when sailing deep downwind (angles greater than 130 degrees). For those long trade wind passages where the wind is blowing over the stern quarters, you need an Asymmetrical Spinnaker (often called an A-Sail or Gennaker).
How it Works
An asymmetrical spinnaker is a massive, deeply cambered, lightweight nylon sail. Unlike a traditional symmetrical spinnaker, it does not require a cumbersome and dangerous spinnaker pole. The tack is attached to the bowsprit, and the clew is controlled by a sheet routed far aft.
When to Use It
The asymmetrical spinnaker is designed to catch and pull the boat before the wind. It excels at apparent wind angles between 120 and 160 degrees. On a catamaran, because the beam is so wide, you do not need a pole to wing the sail out; the windward bow provides a naturally wide sheeting angle.
Handling the Beast
A massive nylon spinnaker can be intimidating for a short-handed crew to hoist and drop. To make handling safe and manageable, bluewater cruisers use two primary systems:
- The Dousing Sock (Snuffer): This is a long fabric tube with a rigid bell at the bottom. You hoist the sail while it is safely contained inside the sock. Once hoisted, you pull a continuous line to raise the sock, allowing the sail to fill. To drop it, you simply pull the sock back down over the sail, smothering it before lowering the halyard.
- Top-Down Furlers: This is a more modern, high-tech solution. Similar to a Code Zero furler, it uses an anti-torsion cable. However, the sail is only attached to the cable at the top (the head). When you pull the furling line, the cable spins, rolling the sail up from the top down, squeezing the air out of the massive belly.
Which Fabric is Best?
For a Code Zero, which must hold a relatively flat shape under high loads, we recommend a lightweight cruising laminate or a specialized reinforced nylon.
For an asymmetrical spinnaker, which needs to be light enough to fill in a whisper of breeze, nylon is the standard. At Kraken Sails, we typically offer two tiers for our cruising spinnakers:
* High-End: Superkote or AirX. These premium fabrics allow us to use different cloth weights within the same sail (e.g., heavier cloth on the highly loaded leech, lighter cloth in the body) because their stretch profiles are perfectly consistent.
* Budget-Friendly: Nylite. This is a reliable, slightly heavier nylon that uses a single cloth weight throughout the sail. It is an excellent, durable option for budget-conscious cruisers.
Equipping your catamaran with the right downwind sails transforms the offshore experience from a frustrating, engine-driven slog into a fast, silent, and exhilarating ride. Contact Kraken Sails today to discuss adding a Code Zero or Asymmetrical Spinnaker to your bluewater inventory.
Kraken Sails – Engineered for the Ocean.