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Types of Spinnakers
Symmetrical vs Asymmetrical vs Gennakers
So, what’s the difference between Symmetrical Spinnakers, Asymmetrical Spinnakers and Gennakers? What are they each best suited for? Let’s find out.
Starting with the basics; a spinnaker is a large balloon-like downwind sail typically used on points of sail between a beam reach and a run. Modern sailboat designs tend to be a little inefficient going downwind and spinnakers help to speed things up. We’re going to cover three types of spinnakers; symmetrical, asymmetrical and gennakers (a cross between a genoa (a big jib) and a spinnaker).
Note: This is a plain english guide so please forgive the lack of terminology if you’re a more advanced sailor.
The key physical differences between spinnaker types
Symmetrical Spinnakers are attached at these 3 points:
- The top is hoisted up the mast typically to about 2/3rds of it’s height.
- The leeward side (side furthest from the wind eg. on the same side as boom) flies freely with a sheet attached coming back to the cockpit.
- The windward side (side closest to the wind eg. opposite side to boom) is attached to a pole and a sheet; the sheet goes back to the cockpit and the pole is clipped on it’s other side to the mast.
The pole is typically supported by two sheets; an uphaul and a foreguy. The uphaul holds the pole up and is connected to a higher point on the mast. The foreguy is attached to a point towards the bow of the boat and pulls the pole forward towards the bow or is loosened to allow it to move further back towards the cockpit.
Asymmetrical Spinnakers are attached at these 3 points;
- The top is typically attached to the top of the mast by a halyard.
- The bottom is attached to a bowsprit (essentially a pole sticking out from the bow of the boat)
- The remaining end has two sheets attached to it, these allow it to be sheeted in back at the cockpit. One sheet is for the port side while the other is for the starboard side.
When the spinnaker is out on the port side for example, the port side sheet will be connecting this end of the spinnaker to the cockpit. If the boat is gybed then the starboard sheet is used to pull the spinnaker around to the starboard side of the boat. The sheet not in use is either led through the gap between the forestay (wire connecting mast to bow of boat) and the top of the bowsprit or if space doesn’t allow then it is led around the front of the bowsprit.
Gennakers are attached at these 3 points:
- The top is attached to the top of the mast by a halyard.
- The bottom is attached to the bow of the boat. ( This is the key difference between a gennaker and an asymmetric spinnaker)
- The remaining end is sheeted back to the cockpit with a similar sheet setup to that described for asymmetrics above.
So, a gennaker is basically the same as an asymmetric spinnaker except it is attached to the bow of the boat rather than to a bowsprit.
Pros & Cons and best use for each type
Symmetrical
Pros
- Well suited to deeper downwind courses from broad reaches to straight runs.
- Large & Powerful sail
Cons
- Can be difficult to set up and handle due to the pole.
- Requires more experienced crew to fly effectively.
- Gybing is a trickier process.
Best Use
Symmetrical spinnakers are best suited for sailing straight downwind (a run). They provide the best power on this point of sail and are one of the few sails suited to this point of sail.
Asymmetrical
Pros
- Easier to handle, set up and gybe than symmetrical due to the lack of a pole.
- Efficient on beam reaches through to broad reaches.
- Simpler equipment
Cons
- Inefficient on runs as they fall into the wind shadow of the mainsail.
- Requires boat to have a bowsprit.
Best Use
Asymmetrical Spinnakers are best suited to sailing between beam and broad reaches. Many competitive sailors find it is faster to sail in a zigzag course of broad reaches using an asymmetrical rather than to sail on a run with a symmetrical. This is made easier by the fact that they are simpler to gybe with also.
Gennaker
Pros
- Requires minimal equipment (eg. no bowsprit or pole required)
- Really simple to set up, handle and gybe.
- Efficient on beam reaches through to broad reaches.
Cons
- Inefficient on runs as it’s also in the wind shadow of the mainsail.
- Less powerful than asymmetrical or symmetrical.
Best Use
Gennakers are best suited for sailing between beam reaches and broad reaches where the boat does not have a bowsprit. It may be more suitable than an asymmetric for stronger winds and /or less experienced crews due to its lesser power and greater ease of use.
Overview
Hopefully you now understand the main differences and best use cases for these sails! To do a quick recap:
To sail effectively on a straight run; use a symmetrical spinnaker. Just make sure you practice the process of setting it up and handling it with your crew as the pole can make it a tad more difficult than other sails.
For the best efficiency and ease of use; consider using an asymmetric spinnaker, it has great power and is a lot easier to handle and gybe with. Best suited to broad reach zigzags downwind rather than straight runs.
For simplicity and ease of use, especially in stronger winds; use a gennaker, it’s basically as easy to handle and set up as a Jib while being considerably more powerful for points of sail between beam and broad reach.
Related Read:
The Top Best Comfortable Drysuits for Dinghy Sailing
The 5 Best Offshore Life Jackets for Sailing
Thanks for reading! Have any questions or feedback? Feel free to leave a comment below.
Bill
Bill has been involved in sailing for the past 11 years and previously worked as an ISA sailing & powerboat instructor.
Thanks for this. So I have never sailed with any of these large spinnaker type sails…but am about to I think. My understanding is there is also a “drifter’ which is more of an upwind light air sail…is that true?
Hi Gerry,
No problem, thanks for getting in touch! Exciting stuff, they are definitely exciting and challenging sails to get started with. A day with lighter winds (5-10 knots) would be ideal for getting to grips with them. So, a drifter is essentially a very lightweight genoa which can be used effectively in light winds when a heavier spinnaker may not fly effectively, here’s a link to a nice article I found about them; https://www.riggingdoctor.com/life-aboard/2018/7/9/most-useful-sail-the-drifter
Cheers and thanks for reading,
Bill