What Do the Wrinkles in Your Sails Mean?

We’ve all seen it, a beautiful boat sailing along on blue water, but with wrinkles in its sails. Why would someone spend all that money on sails that have wrinkles in them? Why are they there? What do they mean? When is it time to buy new sails?

Why are there wrinkles in sails?

Some wrinkles in sails are supposed to be there, they are actually designed into the sail and sewn that way, and increase the overall performance of the sail. Some wrinkles are not supposed to be there and can be signs of poor design or wear and stretching of the cloth.

When are wrinkles in sails a good thing?

Speed wrinkles as they are many times called are a good thing. You will most often see these in new sails, and in many racing sails which are trimmed by professional sailors. These wrinkles are supposed to be there.

They are found in the luff (the leading edge or front) of the sail, usually where it attaches to the mast, forestay, or furler.

Surprisingly, the optimal design of a sail is not a perfect triangle. Sailboat masts and forestays are also not perfectly straight, they are designed to bend just a little bit to allow the sailor to make adjustments.

Designed for Adjustability and Performance

For example, in light wind, generally you want more power and a curved shape in your sails. In heavy wind, you want to be able to have your sails make less power and that can be accomplished by making the sail flatter.

Of course, the conditions are not the same each time you go sailing. When you purchase new sails, the sail designer can optimize the sails for the conditions you sail in, so he or she can make them flatter or with more draft (curved shape) depending on your needs.

Most of us, outside of very specific applications like the America’s Cup, get the best value in our sails when they can be adjusted to suit a variety of conditions. This is where the wrinkles come in.

Wrinkles in the genoa, jib, or headsail

This is where most people notice wrinkles in their sails first. It is also how most new sailors are introduced to this concept when learning how to sail.

Most people see wrinkles and think: “they did not raise their sail enough.” Actually, most of the time this means people are sailing in light air, and have lowered or “eased” the headsail halyard just a few inches, taking the tension off of the front of the sail.

Think of a string, when pulled very tight it is perfectly straight (no wrinkles) but when you let go a bit, it curves some, sagging in the middle. This curved shape adds lifting power to the sail, which helps acceleration and increases speed in light air or wavy conditions, but lots of curve in a sail also adds aerodynamic drag, which can slow you down in smooth water or very windy conditions.

What the horizontal wrinkles are doing is allowing the curve in the sail (draft) to be deeper. When the halyard is pulled tighter in your genoa, these wrinkles can be flattened out, and this makes the draft shallower and further forward.

Wrinkles in the mainsail

The exact same concept applies to the mainsail, but sometimes to an even greater extent. In most cases, it is the same. The mainsail halyard can be slackened just a bit to allow for a deeper setting on the sail, creating more power. When it is windy, the halyard can be tightened to make the sail flatter and control the heel angle of the boat.

To a greater extent, some boats have adjustable backstays (some racing-type boats have even more adjustments like check stays, deflectors, runners, and shroud adjustments) and more adjustable points like the outhaul and cunningham. The backstay allows the mast to bend. If the sail had no wrinkles the sail would have a poor shape when the mast was bent more than normal with the backstay.

Another Example of How Wrinkles in the Sail Work

If you have ever flown on a large passenger airplane and sat next to the wings you may have noticed lots of noises, or even the back of the wing moving in and out as the airplane takes off and lands.

What the pilot is doing by moving these flaps in and out is adjusting the draft in his wings, just like you would do for a sail (kind of).

When the airplane is taking off or landing, it is flying much slower. When the airplane is going slow, it needs more lift and drag does not have as great of an impact. Sound familiar? So in this case the extra flaps come out and create more curve or draft in the wings.

When the airplane is up to speed, the extra flaps are retracted to make the wing flatter, with less drag. Think about this like the F-14 Tomcat in the famous movie Top Gun. When going fast, the wings are swept back and smooth! Your boat is just like an airplane, but flying horizontally through the both water (dense, small wings, keel and rudder) and air (less dense, big wings, headsail and mainsail).

U.S. Air Force photo by Tech. Sgt. Rob Tabor (RELEASED)

Speed Wrinkles are a Good Thing

Of course, sailboats don’t have metal wings with adjustable flaps, so using halyard tension and designing sails with adjustability and wrinkles allows you to accomplish the same thing with your sails (to an extent).

So this means that most of the time when you see small horizontal wrinkles in a genoa, jib, or mainsail in light air conditions this is usually a sign that the sail is designed well and the trimmers have trimmed it properly.

We should rarely see vertical wrinkles in a sail, this means something completely different.

When are Wrinkles in a Sail Bad?

Both horizontal and vertical wrinkles in a sail can also indicate something is wrong, either with the way you have your sail trimmed, the way it is mounted on the boat, how it was furled, how it was stored, or perhaps an error in design or manufacturing.

The wrinkles in this genoa are not coming out!

Vertical Wrinkles in a Non-Furling Sail

Quite often vertical wrinkles in a non-furling sail are a sign the sail has aged and the fabric has stretched past its optimal shape. This is quite common with aged dacron sails, especially if they have been sailed in heavy weather, have lots of miles on them, or were raced hard and often.

When you see this, it is time to talk to your sailmaker about inspecting your sails and possible replacement.

If your new sail has vertical wrinkles, that tells another story altogether. The designer or sailmaker may have a specific reason for this and should be consulted if you have any questions. However, this also means that the stitching of your sail could be less than optimal, essentially there was some binding or uneven stitching while the sail was being sewn.

The bottom line is, when you are seeing lots of vertical wrinkles, it is probably time to talk to a pro about it.

Vertical Wrinkles in Furling Sails

Sometimes you will also see vertical wrinkles in your furling genoa or furling mainsail, often where it meets the furler, and you have the sail partially furled in heavy winds. Usually, this is normal, but not optimal.

The designer can add a foam luff or rope “spacers” in your furling sail to offset this, but often when partially furled a sail will always have some vertical wrinkles near the furling attachment points. This is normal, as remember, we still need that adjustability designed into the sail.

If you have lots of wrinkles at your furling points, it could mean that your sail fabric is starting to stretch, or it could also mean that you need to make some adjustments to your furling technique.

Furling sails will sometimes get wrinkles in the head and tack areas when furled under high tension in a big breeze. It can also happen when furling with too little halyard tension, or not enough backstay tension.

If all of this talk about tension gives you wrinkles on your forehead, it is time to give your local or online sailmaker a call and have him on board your boat to review or send some pictures to discuss. Many times furling related wrinkles can be solved with a few small changes and extend the life of the sail.

Horizontal Wrinkles in New and Stored Sails

Optimally we would always store our sails laid flat or gently rolled, let’s face it though, this is not practical for most boats that are large enough to spend the night on. Most of us have some compromises and at some point have to fold our sails.

Mainsails are normally stored “flaked” or folded on the boom. Over time, continuous “flaking” in the same place will create a fold line or large horizontal wrinkle. Use over time will take these out again, but many of us only use our sail for the day then fold it again and leave it for the week while we go back to work. Wrinkles from flaking or folding a sail are par for the course.

When you receive new sails they usually have to be shipped to you somehow. If your sail needs to go inside of a box, it will likely be “bricked” or folded carefully on itself several times to fit into a box or a delivery van.

In this way, it is completely normal for new sails to have wrinkles, which will start to release over time of normal use.

Should I Use an Iron To Remove Wrinkles from a Sail?

NO. More experienced sailors will likely comment that this should be left unsaid, but no question is stupid if it helps. If you are new to sailing, this may seem like a good option. Unlike your T-shirt or plants, the materials and fibers inside your sail material are all engineered for specific use.

Without going into too much detail, applying lots of heat in some areas of the sail may cause these fibers to interact differently or change shape. This would be a bad thing as your sails are designed to be shaped a certain way for optimal performance. In the case of laminate or membrane sails, you also risk damaging the layers in the sail and completely ruining your expensive assets.

When is it time to buy new sails?

Wrinkles don’t always mean why they say, and they are not a definitive reason why sails are worn, mis-shapen, or need to be replaced. Some “speed wrinkles” are a good thing. Some wrinkles, can mean the sail is worn. If you aren’t sure, our best advice is to call a trusted sailmaker and discuss it with an expert. 

Photos of the situation are always a tremendous help. Sail safe, sail fast (or slow if that is your thing), and have fun!

If you are in need of new sails, we highly recommend you contact our friends at 180 Sails (www.180sails.com) as a long phone discussion with them about our own sails is what inspired this article (we were measuring the mast bend for our mainsail). We use an Evolution Expedition Carbon/Taffeta Genoa on board and we are currently in discussion of a new mainsail from the same material.


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