The keel sticks out the lowest part of the boat hull. The sailboat utilizes long keels, skegs, or blades to hold a straight course.
Keels are one of the most essential elements of the sailboat configuration. Shipwrights often lay the keel as the first major part during manufacturing. The keel is the foundation of the sailboat. It typically includes a considerable amount of ballast to hold the sailboat steady.
Generally, there are various types of sailboat keels.
How Does A Sailboat Keel Work
How Does A Sailboat Keel Work
Generally speaking, the keel of sailboats operates as the water foil. It will help to hold the sailboat on a straight course. The keel also functions similarly with the centerboard or the leeboard with extra fundamental integrity.
Yet, why does a sailboat need one extended keel while a powerboat uses one flat keel? A sailboat does not keep navigating with the wind right behind it. If so, it will not be necessary for a long keel.
To put it another way, a sailboat can sail in almost all directions to the wind. The reason is that the keel will help transfer angled forces to forward motions. If there is not a keel, a strong side wind will merely drive the sailboat sideways or capsize it.
The keel also provides extra stability and lets the sailboat move on without capsizing. A long, heavy keel reduces rolling movements in harsh weather. A thin, sporty keel reduces friction and increases speed in the light wind.
In the next part, we are going to discuss the most popular types of sailboat keels as well as their functions.
An Overview Of Sailboat Keel
If you crave a quick review of sailboat keels, we will offer a list of the most popular keel types followed by short descriptions.
- Full keel: It runs from front to rear. It is the most steady keel type which makes it the most common cruising keel.
- Modified full keel: It runs deep and long like the full keel but with a cutoff at the front. The biggest benefit is to decrease heeling.
- Fin keel: It offers the top performance but provides less comfort. This feature makes it well-known for racing. The fin keel is integrated onto the base and normally runs deep with thin form.
- Bulb keel: It is a variant of the fin keel. It often carries extra ballast in tips, which offers more stability.
- Wing keel: It is a variant of the fin keel. It has two tips at the head of keels, reducing crossflow, increasing directional steadiness.
- Bilge keel: It consists of two fin keels or full kees. It will allow the sailboat to be beached, which makes it the most common keel for tidal waters.
If you want more information, let’s keep reading on.
Types Of Sailboat Keel
The designer and engineer have developed the construction of sailboat keels through the years. Each type of keel varies between sailboats depending on the size and the function of the sailboat.
Fixed keels are typically the essential part of the medium and large sailboat. They include the full keel, modified full keel, fin keel, bilge keel, wing keel, and bulb keel.
A traditional sailboat often utilizes one full (or deep) keel. This extended and heavy keel will flow with the shape of the sailboat. It will cover at least 50% of the hull length.
The full keel runs the length of the sailboat. It is particularly the deepest part at the stern of the boat. The rudder often normally will run deep and match the dimension of the keel.
A deep keel sailboat is generally heavier and displaces a larger amount of water than any other boat with the same length. It also has an extremely deep draft. That fact causes the boat to cruise in the shallow water off-limits in many situations.
A deep displacement hull is perfect in harsh weather. It is rather stable at acute angles. It is because the additional weight and depth of the sailboat body reduce the risk of knockdowns.
Yet, some full keel constructions are likely to heel aggressively to some particular angles. It causes some sailors to feel annoyed. The ‘sweet spot’ angle of full-keel sailboats is normally a little more moving than normal.
Modified Full Keel
A sailboat with a modified full keel
Modified full keels are an upgraded version of out-of-date displacement hulls. It can run the length and the depth of the hull like a full keel with a loss at the front.
The modified full keel is very popular. They tend to create less drag than the old deep keel.
One advantage of modified full keels is a decrease in heeling. This kind of sailboat offers excellent performance, but it is not suitable for shallow water. Similar to the full keel, rudders run long and deep along the modified keel. A modified keelboat is considerably comfortable on the ocean. Still, nothing can beat the full keel.
Types of sailboat keels
The fin keel is rather popular on modern sailboats. They vary in size and depth among numerous vessels. The fin keel normally sticks out from the center of a boat and extends many feet below the bottom of the hull. The fin keel is generally no longer than one-third of the sailboat’s waterline length.
The fin keel usually offers powerful windward performance in comparison with the full keel. They aim at reducing heeling, which can enhance occupant comfort in certain weather conditions.
This type of keel usually includes a layer of steel covering lead. Manufacturers can also weigh the keel down in other ways. This extra ballast will improve stability and balance the sailboat.
Speed is one more big advantage of fin keels. The fin keel sailboat achieves outstanding speeds with the great help of decreased drag.
The racing boat usually employs the fin keel to speed up. However, the fin keel has more benefits beyond competition craft. Increasing some knots of velocity on a long journey can shorten your traveling time. It is the reason why the fin keel sailboat is very common for ocean cruising.
A fin keel typically runs as deep or deeper than a full keel and a modified full keel. Any sailor needs to be mindful of this thing because a fin keel boat running aground can cause serious damages to both the keel and the base of sailboats.
The fin keel is more suitable for coastal and bluewater crossings. Although the fin keel is better for bluewater cruising, it may offer less good feelings than the full keel in cruel weather.
Skeg Rudder Fin Keel
A few fin keels have skeg rudders. The depth of skeg rudders is quite deep and usually equals the depth of keels.
Yet, far from full keels, a skeg rudder and a keel are a large gap apart. In some cases, keels re-emerge right before skeg rudders. It will offer extra protection for this skeg rudder.
Spade Rudder Fin Keel
The quickest fin keel model often consists of spade rudders and long, thin knife-style keels. Fin keels followed by spade rudders have the lowest amount of drag. Then, they can outpace any other keel model.
Still, high speed will come at a cost. Windward performance becomes less efficient and rough water provides less comfort.
In addition, the sailboat with the spade rudder fin keel has no additional rudder protection. All contacts with the base of sailboats can harm the rudder. Rough water and rubbish are also quite undesirable. In some situations, they can pose a severe threat.
Bulb keels are considered a subcategory of fin keels, but this model may deserve its own type. The bulb keel is perfect for the shoal-draft boat. It is because they decrease draft but do not sacrifice a great performance.
The bulb keel is a shortened fin keel accompanied by one torpedo-like bulb at the bottom. This bulb can increase the surface area of fin keels. Also, it does not significantly increase the depth as well as contains the necessary lead ballast to hold stability.
In addition, the bulb keel is more durable to grounding than the traditional fin keel.
Specifically, bulb keels are less steeper. Then, they are less likely to contact the base of sailboats. Yet, unlike the fin keel and the full keel, the bulb keel is blunt. In other words, they will not shear the seafloor like a knife. They are also easier to escape from the muck.
The purpose of wing keels is similar to bulb keels. Still, the accomplishment is quite different.
The wing keel is a shortened fin keel with a horizontal outcropping part at the bottom.
If you look at the wing keel from either the front or rear, it looks like a T. This overturned ‘T’ shape protrudes from the bottom of the sailboat.
This kind of keel is excellent for shallow water. They also provide considerable balance and windward performance.
The bilge keel is a type of keel including various keels. Bilge keels are possibly the most magnificent shoal draft transformation for fixed-keel models.
Rather than only one extended keel in the center, the bilge keel sailboat features double shortened fin keels on two sides of the base.
They stick out at opposite angles. It will help to reduce draft and come into vertical alignment when sailboats heel over.
Double-keel sailboat performance can vary widely, but this kind of vessel can make impressive seaworthiness.
Grounding is not the endpoint of your voyage since the bilge keel allows the vessel to stay flat on the mud but not dig in. Thanks to double bilge keels, it is not necessary to sweat them when tides go out.
How To Choose The Most Suitable Keel
There are some main factors that will decide the most suitable keel for your boat. They consist of velocity, movability, and comfort.
Every type of sailboat will require different features. The liveaboard will take interest in balance and comfort at first. The cruiser will pay more attention to comfort and velocity. The daysailor will want a shoal draft and excellent movability.
As a result, which type of keel is the most suited for you will all come down to which type of sailor you desire to be.
For every circumstance, the following keel type is normally a good bet:
- Cruises: the modified full keel or the fin keel features a skeg rudder.
- Coastal liveaboards: the full keel
- Coastal daysailors: the fin keel features either a skeg rudder or a centerboard.
- Racing boats: the fin keel or the wing keel.
Which Type Of Sailboat Keel Is The Best?
The most steady and trustworthy keel is the full keel. This type of keel has the greatest weight and the most length. It is also the most durable.
The full keel is completely integrated into the hull of sailboats. It can reduce the chance of damage if the boat runs aground. Its heaviness will ensure maximum heel decrease.
Although it will depend on the way of using the boat, the full keel is typically considered the greatest keel for almost all sailors. Yet, it is quite slow. If you are looking for great performance, the recommendation is to pick up the fin keel.
Which Type Of Keel Is The Best For Offshore Sailing?
The most suitable sailboat keel for offshore sailing is the full keel or the modified full keel.
The full keel decreases heeling the most. It also provides the greatest directional stability among various types. These two functions are very essential in weather conditions on the ocean. Because there will be wind power and wave drag that can affect your boat’s straight course negatively.
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There are various types of keels to match each sailboat in a certain water area or the length of voyages. However, when it comes to the most suitable sailboat keel, you will need to consider three main factors: speed, movability, and comfort. Windrider of The Rockies!
After all, the best sailboat keel is the full keel. It will cover all features and can handle the most problems on the water.
Reference: Boat Keels & Fins: 7 Types Explained