Spinnaker Or Gennaker?

Spinnaker or Gennaker?

Light-weather sails

For our Catalina C36 yacht, we’ve been comparing the characteristics of various types of light-weather sails. A number of types are available for light-weather conditions, for example:

  1. halfwinder
  2. tradewind sail
  3. gennaker
  4. spinnaker

Our goal was to select a sail that best suited our needs. But what are the characteristics of these sails?

Halfwinder

A halfwinder is basically a very large genoa. It is attached to the bow and to the top of the mast. The halfwinder is best suited for reaching. Although designed for broad reach or down wind courses, it can also be applied on more close-hauled courses provided the conditions are light. The use of a spinnaker pole is not necessary, and this type of sail is therefore suited for small crews. The halfwinder is sometimes confused with a ‘cruising spi’. (However, a ‘cruising spi’ is actually a type of gennaker.) The halfwinder is operated with a single sheet.

Halfwinder.

Tradewind sail

A tradewind sail is similar to the afore-mentioned halfwinder, with the distinction that it is attached to the front stay as well. A DRS (drifter reacher spinnaker) is in some languages confused with a tradewind sail; as indicated by its English name, the DRS is most suited for reaching. The DRS is basically an asymmetric sail, bigger than a genoa and smaller compared to a gennaker. A DRS can’t be operated with a genoa furler. The same holds for the tradewind sail. A tradewind sail is a double halfwinder, consisting of two identical sides, each carried at one side of the ship. The tradewind sail is perfectly symmetric, but it can be used either unfolded or folded to one side of the boat. (In the latter case, both parts of the sail are used as a double-layered ‘normal’ sail. Its surface area is reduced to 50% by doing this). A tradewind sail is operated with a spinnaker pole on the windward bow, and can be used with or without a pole on the leeward side.

Tradewind sail.

Gennaker

A gennaker is an asymmetric spinnaker. It is sometimes called ACS (asymmetric cruising spinnaker). A gennaker is used with two sheets at a time, and is attached to the bow (but not to the front stay). By adjusting the tack line, the gennaker can be used ‘flying’ free from the bow of the ship. A gennaker is used with or without a pole, and can be used at somewhat more close-hauled courses compared to the sails described above. The use of a bowsprit is optional; this will increase the maximum tolerable dimensions of the sail to be used on the ship. The gennaker may be used in conditions up to 20 knots approx. If the sail is employed on starbord, the port sheet runs in front of the bow, to the tack on starbord side (outside the ship). When changing course (gybing), the gennaker turns over the water, around the forestay; in contrast to a normal genoa/tradewind sail/halfwinder that all move over the front deck.

Gennaker.

Spinnaker

A spinnaker is symmetric, and is (in contrast to the gennaker) always used free from the bow (‘flying’). There are 3 types of spinnakers, depending on how the fabric of the sail has been stiched together: full-radial, tri-radial and radial-head spinnakers. Full-radial spinnakers exist in 2 subtypes: runner-type (for true downwind courses) and the somewhat smaller reacher-type (for beam/broad reach). Both subtypes are fabricated with heavy (15-30 knots wind) or medium (10-20 knots) quality cloth. Tri-radial cut spinnakers are designed for beam reach to downwind courses and are mostly used with a pole. Radial head spinnakers are always used with a pole, and are designed for similar courses as the tri-radial spinnakers. Gybing with a spinnaker does not involve (unlike the aforementioned gennaker) any sail-turning; however, the spinnaker pole needs to be changed from port to starboard or vice versa. Finally, a spinnaker is attached with a port- and starboard sheet simultaneously. More information about the various spinnaker/gennaker cuts you can find on this page.

Spinnaker.

 

Code Zero

Up to this point, I gave you a short description of the available sails for light-weather conditions. But there is still one missing in the original list: a code Zero (code 0). The dimensions of the code zero are in between a genoa and a gennaker; this makes the code zero ideal for close-hauled courses in up to 10 knots of wind. The big distinction between a code zero and the 4 types of sails discussed earlier is therefore its intended use (closed hauled vs broad reach courses). Code zero sails are used with their independent furling system and are very popular in races since they do not have much impact on the boat’s handicap.

Choosing the right sail

The figure below shows the various sail types and the conditions they are most suited for.

We chose the asymmetric gennaker for our C36 because:

  • you can use it without a pole
  • ideal for short-handed sailing
  • less at risk for chinese gybing (although it can happen with a gennaker as well)

Choosing accessories

Our main dilemma proved to be the last decision we had to make: how are we going to lower the gennaker, with or without a snuffer? (A snuffer is a very big sock-like cover with an oval ring on top, forcing the cloth into the cover as it is pulled down.) Another option is to use a top-down furler. Important things to decide before ordering your sail, since the dimensions of the new sail depend on it. Pros and cons of these options are:

  • top-down furlers are expensive (starting at 2.000,- eu)
  • top-down furlers are not suited for higher wind speeds (as I’m told…)
  • using a snuffer involves a larger number of actions (hoisting the snuffer, removing the snuffer before the sail opens itself)
  • the snuffer can only be lowered when there is no or little pressure in the gennaker; however, the same holds for lowering a gennaker without a snuffer
  • when using a snuffer, the maximum sail area you can use is smaller (because the snuffer uses about 30cm of forestay length, see picture below)
  • snuffer is often recommended for smaller crews
  • a gennaker is more easy to clear away from deck in a snuffer, but also more easy to prepare for launching

Snuffer.

Having studied all of the available information (or at least, we tried to), we decided to purchase a new gennaker for our yacht, and to use it without a snuffer or furler. We asked for some quotations, and noticed big price differences between standard size gennakers and custom made gennakers. Custom made sails are ideal if you don’t want to compromise on dimensions or color patterns/cuts. But in our case, a standard sail would do just fine and save a lot of money. (Let’s be frank: you can only spend it once.) The last thing we did before ordering was to measure the gennaker halyard, in order to select the most suitable standard size sail. We additionally ordered a turtle bag for the gennaker.

Turtle bag.

Using the gennaker

We definitely needed some time getting used to operating the enormous new sail. The first time, we were so distracted launching it, that we nearly bumped into another boat. The second time, I made the classic mistake of holding one of the gennaker sheets in my hand. This resulted in very painful burns on my fingers. And me not wanting to use it ever again! But then we ordered the snuffer anyway, making our life with this big sail more easy. Athough I will never launch it again without putting on my gloves first….!

Two weeks after the gennaker sheet accident.

After use, the gennaker and snuffer are put inside the turtle bag and stowed below deck. Nice-to-know fact: the snuffer with its oval ring is almost as heavy as the gennaker plus turtlebag plus sheets together (!). And because we ordered a standard size sail, we had an additional 30cm left to employ a snuffer anyway.

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