Most modern sailboats don’t need big overlapping headsails to ensure performance when sailing upwind. In the old days, sailboats were really heavy, their keels were long, and the sail area was the most crucial part that made the boat moving. However, nowadays light masts and rigging are available and facilitate many things while sailing. For example, if you increase the mast’s height and apply a high-aspect sail plan with a jib that overlaps no more than 105%, well this is quite an efficient rigging. So, are you are thinking of going offshore and wondering what sails are the best for your sailboat? Do you want to clarify the difference between a jib and a genoa? Then, follow me and keep reading!

Description of a Genoa

The main characteristics of a genoa are its shape and size. Genoas go past the mast, are triangular, and tend to overlap the mainsail, to some extent. It’s also one of the many headsails that can be set on a Bermudian rig. The numbers 130,150 etc refer to a percentage that has to do about the relationship of the length of the foot of the genoa and from the forestay to the front of the mast. As a result of this operation, i.e. the Luff Perpendicular divided by J (the distance), you get the overlap percentage of the sail.

Keep in mind that the larger the number you get the larger the sail would be. In general, in order to measure genoas, we often use the length of their Luff Perpendicular. In order to construct the LP, you can draw a line from the sail’s clew to the luff, and carefully intersect the luff at the right angle. 

Description of a Jib

The Jib is also a triangular sail that increases sail area and improves handling. Therefore, it increases the sailboat’s speed. Basically, the mainsail controls the stern of the ship whereas the headsail, which sits forward the mast, is most of the time a jib. One of the main functions of the Jib is that it funnels the airflow along the front of the mainsail. This improves the airflow. Moreover, the jib gives control over the bow of the boat, thus making it easier to maneuver the boat. There are different sizes for a jib with the smallest being a storm jib.

In case the boat has a furler, then the size of the genoa or jib can be adjusted according to the wind’s strength, direction, and speed. Usually, jibs are 100% to 115% LP and are used in areas with strong winds. Also, a jib won’t be longer than 115% LP of the fore-triangle dimensions. Lastly, to ensure better performance in high wind speed the smaller area of the jib the better.

>>Also Read: Names of Sails on a Sailboat

Genoa VS Jibs – What Is The Difference Between Them?

Generally, Jibs and Genoas are triangular sails that are attached to a stay in front of the mast. Jibs and genoas are employed in tandem with the mainsail in order to stabilize the sailboat. They usually run from the head of the foremast to the bowsprit. A genoa is like a jib but is larger and reaches past the mast. But, as aforementioned, when the jib overlaps the mast we refer to it as a genoa. Also, a genoa overlaps the mainsail to some degree. Both sails are measured by their Luff Perpendicular percentage, i.e. the area within the fore-triangle that they use. Sometimes, there are large genoas that cover the majority of the mainsail. This mainly happens in light wind conditions where the most sail area is used to increase performance.

And again, when the headsail doesn’t overlap the mast is considered a jib. On the other hand, an overlapping sail is a genoa. Generally, smaller jibs are more lightweight, less expensive, and easy to handle. Jibs might also have a better lifespan as their leeches aren’t dragged across the mast, shrouds, and spreaders. So, all these characteristics make the jibs easier to trim and change. Furthermore, as they weigh less they will heel and pitch less. Lastly, keep in mind that there are different sailcloths weights, and materials that can be used on jibs and genoas. The sail design of each sail is always based on the type of sailboat and the sailing conditions will determine the sailcloth’s weight.

Having Multiple or Less Sails on your Sailboat

In case your sailboat has a larger genoa then you ought to think about getting a smaller headsail. For example, a sail with an LP of around 115% or maybe less. You can use the smaller sail when the wind is getting stronger and keep your genoa in storage. It’s essential to store, protect, and generally take care of your sails a few times per year. So, it’s recommended to often change your sails once in a while. Remember that for every boat has its own sail plan. For example, a boat might need one, two sails, three, etc that will enhance its performance. Each one used for different weather conditions and for different sailing plans.

The rule of thumb says that the fewer the sails less the drag will be. Meaning that you can sail higher to the wind with a single sail rather than having multiple sails of the same aspect ratio and total area. Furthermore, for the same total sail area and same geometrical shape, having multiple sails means that they’ll be less tall. In other words, they’ll catch slower wind closer to the ground. However, for the same total sail area, multiple sails will provide less heeling. This means that you can have lighter structures that support them.

Sail Area and Furling

In the old times, boats used to have long and shallow keels therefore it was crucial to fly a significant amount of sail in order to produce horsepower. But, when a vessel has a light material construction, light masts, and rigging then the height of the mast can be taller without having an effect on the righting moment. So, an overlapping jib, around 115%, results in more efficiency and less dependence on the additional overlap. But, when furling away sail shape from a large genoa you might reduce the sail’s shape efficiency. This is because when using a genoa for strong winds, it’s going to gradually cause an uneven stretch to the Dacron.

Remember that not all sails suit for all kinds of boats. Some boat owners might recommend a specific sail for a specific vessel. But the most important factors that determine what sails suit your boat are the location in which you sail, the type of the vessel, and the captain’s experience. For example, a sail made for Oceanis 331 in Florida will be completely different than a sail made for the same boat that sails in the Meditteranean.

But, what is the best sail size for cruising boats? A 130 or 135% headsail is great because this sail shape is flat thus can be reefed efficiently. However, a 130% headsail doesn’t have a good sheeting angle but is great for offshore sailing. On the other hand, non-overlapping headsails have a narrow sheeting angle so they’re not appropriate for offshore sailing.

In general, light-air sails are large sails and need adequate camber depth to work in light winds. So, when rolling them up and use them reefed you can’t take in enough of the camber to make the sail work windward. And that’s why there are several roller-furling headsails that include lengths of rope or a strip of dense foam that runs along the luff of the sail from the head to the tack.

Apart from that, any sailboat traveling offshore is going to need a small 130% headsail in order to withstand harsh weather conditions. It’s always better to use more than one headsail when voyaging overseas. Last but not least, don’t forget to take into consideration the trade-offs when sailing upwind.

Improve your Sailboat’s Performance

As aforementioned, remember that the most crucial factors that determine the right sail size for your sailboat are the type of your vessel and the kind of passage you’re planning. There are certain things that you can do to improve your sails’ performance, no matter the kind of headsail you have. The first one refers to adding a means of adjusting the sheeting position when reefing and unreefing the headsail. For instance, you can add a block-and-tackle system that can pull the genoa lead forward when the sail is reefed. And when unreefed you can ease it aft. Generally, when moving a lead forward or aft, this changes the angle at which the sheet pulls down on the clew. And when pulling the clew down it trims the top of the jib, but when moving it aft it opens the top of the jib.

The Bottom Line

Modern technology and sail engineering have improved the development of sailcloths, sails’ versatility, and design tools to enhance their performance. Nowadays, you can choose between different types of sails according to the type of your sailboat, location, and experience. So, what’s the difference between a jib and a genoa? In order to clarify the main difference between a jib and genoa you should bear this in mind: When the foot of the headsail is longer than the distance from the forestay to the mast then we refer to a Genoa. Otherwise, the headsail is called a Jib. Basically, a genoa is a large jib that reaches past the mast and overlaps the mainsail. I hope that by reading this article you made clear the difference between a jib and a genoa and how you can enhance your sails’ performance. Wish you a lot of adventurous voyages to come!