What Is Sailboat Reefing System


An effective and efficient reefing system is capable of making any sailboat, whether an ocean cruiser, offshore racer, or a small weekender, safer, faster, and much easier to handle. The term reefing system simply refers to how the surface area of the sail is reduced.

While the majority of both experienced and beginning sailors know that sail reefing systems do exist, they may not know how they work. In this article, we will focus on looking at different sail reefing systems, how they work, and the benefits they offer sailors. If you have been reefing your sailboat using only one reefing system, this is your chance to know whether there are other sail reefing systems you can try.

The Common Sail Reefing Systems

1. Slab Reefing System

The common choice for the majority of modern yachts is the slab reefing system. In most instances, typically 3 reefs are usually pulled down progressively to shorten the sail as the wind increases.

If you make sure that this reefing system is optimized before grabbing your sailing bag and heading out to the open waters, you should have the ability to tuck the slab reef in approximately 60 to 90 seconds, on your own. If you are yet to invest in sailboat winches, you should be able to tuck the reef alone for boats up to 40 feet without too much effort. If your boat does feature electrically powered winches, the boat length can be realistically increased to approximately 50 feet.

The majority of slab sail reefing systems do suffer from issues that often make the reefing not only time-consuming but also a crew intensive core. The most common issue is where the sailboat halyard is led aft to be handled at the boat’s cockpit and everything else is supposed to be handled at the mast.

While this could work well if you have a strong crew, it could be a different matter if the majority of the people on your boat are new to sailing or when you are sailing short-handed. Additionally, this could be a problem if several of your crew members become incapacitated by seasickness.

Another major problem is too much friction. This is generally acute on sailboats which feature banks of similar coachroof clutches. These were near-standard for 2 decades from the mid-1980s. While it is easy to underestimate the effect of friction, it could easily double the loads on the reefing, which could end up making shaking the reef out unnecessarily difficult.

How Can Sailors Optimize the Slab Reefing System?

If your slab reefing system features a good layout, you will not have to deal with the problems we have outlined above. While handling everything, including the halyards, at the masts can be considered to be a traditional arrangement, it has the advantage of ensuring that the friction is minimal. This means that just a single person should have the ability to handle the halyard, ensure that the luff cringle goes under the hook available at the gooseneck, make sure that the leech pennant is tight, adjust vang, and even top the lift as required.

It is, however, worth noting that having the ability to reef from the security and safety of the cockpit has benefits. If after wearing your sailing pants and shorts you will be boarding a sailboat in which the main halyard and leech reefing pennants have already been led aft, the ideal and easiest adaptation is to take a pennant from every luff cringle to the clutches available at the sailboat cockpit.

Ideally, the luff cringles are supposed to be slightly further back than for the boat sails, in which you hook the cringle at the gooseneck, over the ram’s horn. If the reefing and halyard lines are led aft, they should pass through the smallest angles as possible, keeping in mind that the friction increases as the angle at which a line is deflected increases.

If when rigging the sailboat you ensure that the single-line sail reefing systems are set up properly and they feature a low-friction pulley system, you should have significantly fewer issues with reefing. The only issue with the single-line reefing is that you can only use it with the initial 2 reefs. However, this issue can be easily fixed by running the luff pennant aft so that none of your crew needs to leave the cockpit.

2. Lazyjack Reefing System


If you have been wearing your sailing jacket for a while now, you probably already know that the Lazyjack reefing system is not used alone. The system is often used in conjunction with the slab reefing system to ensure that the sail stays under control when you are lowering it. In most instances, the sail almost self-tows between the Lazyjack system lines.

If your sailboat does feature the Lazyjack reefing system, some of the limitations you should expect after wearing your sailing boots include:

  • Increased complexity
  • A marginal increase in windage
  • A chance of the battens getting hooked in the lines when you are hoisting your sail.

Due to the above limitations, the Lazyjack reefing system is not included in boats whose length does not exceed 30 feet. As the boat length increases, the reefing system does offer a bigger advantage. The Lazyjack reefing system makes it possible for a single person to lower and also stow the mainsail of a yacht whose length ranges between 60 and 70 feet, in just a couple of minutes.

3. In-Mast Reefing System

This is one of the sail reefing systems featuring a wide range of benefits. If the boat you will be boarding after wearing your sailing gloves features the in-mast reefing system, all you will need to do is ease the outhaul and then pull in on the boat’s reefing line to reduce the mainsail to the ideal size. To set the sail, you won’t need to spend your time heaving up the rig, simply reversing the reefing process will be enough.

When considering the in-mast reefing system simplicity, appreciating its drawbacks in comparison to the slab reefing system is a good idea. The biggest drawback is that it does not offer an ideal sail shape. The shape is usually relatively flat after setting the full sail and fuller when deeply reefed. If you ask anyone who has the sailing experience, he or she would tell you that this is the wrong way round.

If you check a mainsail using the in-mast reefing system, one thing you will notice is that it is smaller than the slab-reefed mainsail. This is because the length of the luff is generally reduced to accommodate the furling gear top swivel. Since the conventional battens cannot be used, the sail features a negative roach.

It is possible to find sailmakers who offer vertical battens capable of rolling neatly around the furling foil. The battens may allow a modest roach amount. Some cruisers using the in-mast reefing system opt to rig specifically for roller furling, in most instances, with a taller mast to allow for the sail area reduction. Despite these improvements, it is worth noting that both the stability and performance will still suffer compared to a sailboat featuring the slab reefing system, considering that there will still be more windage and weight aloft.

4. In-Boom Reefing System

Some companies do manufacture booms capable of allowing the full-batten main to be rolled into the boom. This system, when compared to the in-mast reefing system, offers a more boating system. If the reefing system happens to fail or jam, it is possible to drop the sail to the boat’s deck and get it down. On the other hand, if the in-mast reefing system jams, you will be stuck with a portion of the sail flapping in the wind.

The in-boom reefing system works perfectly on large boats where the boom is too high to furl and cover the main. The in-boom reefing system can be a retro-fit for an older boat. In some instances, it can be specified for new sailboats.

Globo Surf Overview

Having an ideal reefing system on your boat can make your life much easier once you wear your sailing hat and head out to the ocean. As you have probably noticed, some of the sail reefing systems do allow a single sailor to reef the sails pretty easily while others require crew members to work together to achieve the required sail surface area. If you will be short-handed when heading out with your sailboat, investing in a reefing system that you can use on your own is a much better idea.

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Globo Surf
My name is David Hamburg. I am an avid water sports fan who enjoys paddle boarding, surfing, scuba diving, and kite surfing. Anything with a board or chance I can get in the water I love! I am such a big fan I decided to start this website to review all my favorite products and some others. Hope you enjoy!