Why Does A Sailboat Need A Keel?

If you have ever seen a historic, old fashioned wooden boat out of the water, you have probably been impressed by the gigantic structure that shoots out from under its belly. Old-fashioned sailboats had majestic keels with beautiful, graceful lines to help them navigate through the ocean. Today, most sailboats have some kind of keel as well.

Why Does A Sailboat Need A Keel?

Why does a sailboat need a keel? A sailboat needs a keel to avoid capsizing when the sails fill with wind. A keel also makes it possible to steer without sliding to the side, especially when going upwind. Without a keel, boats are much harder to steer and more likely to capsize.

Here is everything you need to know about why sailboats need keels, as well as different options for choosing a keel for your boat and how keels differ from daggerboards. 

What Does A Keel Do?

The keel serves two essential purposes for your monohull sailboat:

1. It keeps your boat from tipping over. The keel serves as a ballast for your boat, keeping your boat from flipping over when the wind fills the sails.
2. Helps with steering. The keel keeps your boat from sliding sideways when the sails fill with wind, enabling the boat to go straight

Multihull sailboats need help from a keel or daggerboard with steering, but tipping over isn’t a concern in the same way as it is for monohulls. 

What Is A Keel?

The keel is a thin, flat blade that goes down from a sailboat’s underbelly into the water. Keels come in a variety of styles, but all keels are heavy at the bottom with something called the ballast.

Traditional

Traditional keels are built into the hull, creating a fluid, graceful line. This is how old-fashioned wooden boats were built. Generally, the keel would have been built of whatever the boat was built of. 

Traditional keels are still built today. They may be created of fiberglass, wood, or aluminum. The ballast is typically lead. This design is time-honored and still very effective, especially for cruising boats that have a tendency to run aground. 

A traditional keel is much less likely to be damaged by a reef or flat. However, traditional keels tend to be slower. This is becuase the keel creates resistance when it drags through the water.

What Is A Full Keel Sailboat?

A full keel runs over at least 50% of the hull. These sturdy keels keep a boat from tipping over at the bow or strern, even in rough water. They also help a boat to turn to the waves and take less damage if they run aground. 

Fin

These keels offer much higher performance than traditional keels. They’re usually made of lead and bolted to the bottom of the hull. Fin keels have a very streamlined, modern appearance.

They offer a ballast just as the traditional keel does, but they are better at stopping the boat from going sideways when the sails fill with wind. 

For this reason, fin keels are typically used for boats that often sail to windward. A fin keel doesn’t just work as a ballast. It acts as a wing to streamline your boat’s movement through the water.

Which Keel Is Better For What Boat?

These keels offer very different advantages. The traditional keel, especially a full keel, is generally best for bluewater sailboats that spend most of their time on open water.

The fin keel is best for cruising boats who need a lot of maneuverability in shallow water or close quarters and racing boats that need the best possible handling. 

Daggerboard Verse Keel

Both the daggerboard and keel serve the same purpose on a sailboat: They both provide ballast to keep the boat going in the direction you want to go and keep it from tipping over. However, daggerboards are used for multihull boats, which do not need as much help staying upright. 

The daggerboard is more dedicated to keeping the boat going in the right direction and helping you steer. That said, some multihulls do have a keel. Here are some important differences between daggerboards and keels.

• Daggerboards are faster. A multihull equipped with daggerboards will generally go faster than one with a fixed or fin keel. This is because they are able to have the same or superior steering but not as much weight as a keel.
• Daggerboards help your multihull sail into the wind better. If you do a lot of upwind sailing, you’ll appreciate how daggerboards help you maintain an upwind reach.
• Daggerboards draw less. Daggerboards can be lifted up, dramatically reducing what your boat draws.
• Daggerboards are more expensive. Daggerboards are constructed in pairs for multihull boats and they need a pulley system to raise and lower them, so they can cost considerably more than a keel.
• Daggerboards are more delicate. If you’re worried about going aground, you can pull up your daggerboards to protect them. However, it can be hard to predict when you are about to run aground, and many sailors forget to pull up the daggerboards, resulting in expensive damages. 

Which Boats Should Have A Keel And Which Should Have A Daggerboard?

For many boats, the keel and daggerboard can be interchangeable. Many boats are made with keels instead of daggerboards because daggerboards are more expensive. Here are some cases when the daggerboard might be important to you.

• Boats that are used in shallow draft and open water. Daggerboards give you the versatility to drop them for very good ballast and control in deep water and raise them up entirely for safe shallow draft sailing.
• Speed is important. Daggerboards make boats go faster, so choose a daggerboard if you want your multihull to move as rapidly as possible.

When Is A Keel A Better Choice?

• Most monohulls. Most monohuls benefit from a keel because they need more weight and ballast than a daggerboard can offer.
• Boats that run aground often. Be honest, if you aren’t confident that you can predict when you might run aground, it’s best not to put a daggerboard in danger of running aground frequently, as they are considerably more delicate.
• More affordable sailboats. Daggerboards cost more, so if you want a lower-cost sailboat, a keel is probably a better decision for your money, unless you have an excellent reason to choose a daggerboard. 

Do Small Sailboats Have Keels?

All monohull sailboats need a keel or daggerboard to keep them from capsizing or sliding sideways across the water when their sails are full of wind. Multihull sailboats also need a daggerboard or keel to help them avoid sliding sideways and steer upwind. 

Daggerboards are more common on small sailboats, and they may be removable. They frequently lift up and down on smaller sailboats. 

What Else Can You Do To Keep Your Boat From Tipping Over?

If you are worried about capsizing, you’ll want a sturdy boat with a good daggerboard or keel.

However, there is more that you can do to keep from capsizing. Here are some tips to avoid ending up in the water on your next trip.

• Choose the right size sails for your boat. Don’t be tempted to go up a size in sails, especially if you’re not an experienced sailor. Larger sails make it much easier for a boat to flip over.
• Only use a Spinnaker in predictable, calm conditions. It can be very alluring to throw up the Spinnaker on a calm afternoon, even if there are thunderstorms on the horizon. However, you should think very carefully about putting up this large sail if there may be a storm. A sudden gust of wind that catches the spinnaker could easily send your boat over.
• Use all of the weight at your disposal. Your weight and the weight of your passengers is important on a small sailboat. To keep your sailboat upright while maintaining high speeds, lean over the windward side to help balance out the boat and keep it from tilting over and capsizing. 
• Use your daggerboards in heavy weather. If you are in a multihull sailboat and heavy surf, you can use your daggerboards to keep your boat from capsizing. Adjusting the daggerboard can let you avoid tripping your boat up and capsizing. 

What If You Run Your Keel Aground?

The keel is the deepest part of your boat, so the chances are good that if you are going to run aground it will be the keel that takes the damage. Running your keel gently aground on sand or mud is unlikely to do any damage. 

However, if you hit reef or rock with any kind of speed, you can crack the keel or even drive the keel from the hull, cracking the hull.

Do Power Boats Have Keels?

Most powerboats don’t need keels. Powerboats are propelled from behind, rather from the side like a sailboat. That means that they don’t have sideways pressure to resist and they don’t have the tendency to tip over as sailboats do.

 Some of the fastest powerboats, such as cigarette boats, may have a keel and ballast so that they don’t flip over backward when they are under full power.