Common Furling Mainsail Problems

Common Furling Mainsail Problems

Sailing is a fun and rewarding pastime, but it can be challenging to keep your vessel running smoothly. A boat’s furling mainsail should be in tip-top shape to efficiently move it during a day of cruising. However, there may be some issues that can arise when it comes to managing your sails.

The common furling mainsail problems are broken or damaged battens, sail luff roundness, too much pre-bend, incorrect leech tension, and excessive weather helm.

As a sailor, you know how important it is to keep your sails in good condition. They can be difficult to maintain, as they are often exposed to the elements and require regular upkeep and repair. Read on and discover how to address the challenges of your boat’s furling mainsail so you can sail away to your next trip without any hitches.

Broken or damaged battens

Common Furling Mainsail Problems

Battens are a key component of the mainsail furling system, providing support to keep the sail luff round. When they break or become damaged, they can cause an issue with the sail’s shape and performance.

It is prudent practice to inspect them closely and make sure they are in good condition. You should also check the batten pocket stitching to make sure it is secure. If any of the battens are bent or have cracks, they should be replaced. Should you find that the battens don’t fit snugly in the pocket or have excessive movement, they should be adjusted or replaced as needed.

Sail luff roundness

When the sail luff is not properly round, it can cause problems when furling or unfurling the sail. As the mainsail is unfurled, a luff with too much fullness (or “puff”) can make the sail difficult to manage, causing it to wrap around the forestay, while a luff with not enough fullness will result in an unattractive appearance.

To determine if your mainsail has the correct luff roundness, check for even distribution of tension along the length of the luff and across its width. If you find that your sail’s luff roundness is off, there are a few ways to address the issue. 

First, check to make sure that all of the battens are correctly placed and undamaged. If the battens are fine but you’re still seeing issues with luff roundness, you may need to adjust the leech tension of the sail. This can be done by either manually tweaking the tension on the leech line or by using a downhaul system. If all else fails, consult a professional rigger who can give you more detailed advice on how to fix the problem.

Removing a Furling Mainsail: 4 Steps

Too much pre-bend

One of the most common furling mainsail problems is too much pre-bend in the luff of the sail. Pre-bend is when the luff of the sail curves forward more than necessary, resulting in poor aerodynamics and an inability to shape the sail properly. A variety of factors, such as incorrect halyard tension or mast bend can cause this.

To adjust the pre-bend on a furling mainsail, you will need to adjust both the halyard tension and the mast bend. The halyard should be adjusted first; start by releasing tension until the sail is flat and then gradually increase tension until the correct pre-bend is achieved. Once you have done this, you can then adjust the mast bend to match the desired pre-bend.

When adjusting the pre-bend, it is important to remember that too much pre-bend can cause excessive weather helm and reduce the effectiveness of the sail. It is best to err on the side of caution when adjusting the pre-bend, making sure that it is not set too high.

Incorrect leech tension

Common Furling Mainsail Problems

Incorrect leech tension occurs when the leech of the sail (the back edge) is not properly tightened, allowing the fabric to become loose and flutter in the wind. This can cause the sail to lose power and performance, and it can be difficult to control the boat.

To fix this issue, you’ll need to adjust the luff and leech lines, which are typically made from either rope or webbing, and run along the entire length of the sail. You’ll want to make sure that they are taut and evenly tensioned so that the leech of the sail is tight and firm. Once you have set these lines correctly, you should be able to feel the difference in performance immediately.

If you’re still having problems with incorrect leech tension, it may be necessary to adjust the shape of the sail itself. Depending on your particular setup, you may need to use a sail shape adjustment tool or even an adjustable track. This will allow you to tweak the sail shape until you get it just right.

How to Reef a Roller Furling Mainsail

Excessive weather helm

Excessive weather helm is a common problem with furling mainsails and occurs when the mainsail is not properly balanced. This means that the sail generates too much power to the leeward side of the boat, causing it to turn into the wind rather than away from it.

To solve this problem, adjust the pre-bend and leech tension of the sail as necessary, then adjust the traveler and outhaul settings on the boom to ensure an even spread of pressure along the sail’s foot. 

You may need to make sure that your mast is in the correct position relative to the boat and that it is completely vertical. Then, try trimming the sail slightly differently, or adjusting the rigging or sail shape until you find a setup that works.


How to Remove a Mainsail From an In-Mast Furler for a Beneteau Unit.

Mainsail furlers are an invaluable tool for sailors, allowing them to quickly and easily adjust their mainsail while underway. However, they can be prone to problems, such as broken or damaged battens, sail luff roundness, too much pre-bend, incorrect leech tension, and excessive weather helm. It’s important to be aware of these common issues that can arise and the steps you can take to troubleshoot and fix them.

Changing a Mainsail Furler to a Standard

Frequently Asked Questions

  • What should you do to maintain your in-mast furling mainsail?

To ensure your in-mast furling mainsail is properly maintained and cared for, it’s important to regularly inspect it for wear and tear, clean it after each use, and have it professionally serviced at least once a year.

  • What is the slowest sailing point?

Perhaps the “easiest” attitude of sail, dead downwind is also the slowest. On a reach, modern boats routinely sail faster than the true wind speed due to the phenomena of apparent wind.


This blog post is provided for informational purposes only. The information contained is not intended to constitute legal advice or to substitute for obtaining legal advice from a qualified attorney.

Shawn Chun

Aloha! My name is Shawn and I Love the Beach and Ocean! From surfing to beach sports to boating and fishing I like it all. More importantly, I Love the people I get to meet who also share a passion for the sand and surf. Living and growing up near the ocean my heart has always been connected to the beach and its lifestyle. I wish to share my experience with those around the world. Mahalo (Thank You) for visiting and enjoy your stay here on my site!

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