A keel is an element of the hull of watercraft, including yachts. Although it is almost unnoticeable, it is responsible for the boat’s stability and maneuverability in difficult weather conditions. On its type and design depends not only the sailing comfort, but also the performance of the yacht. Find out exactly what a keel is in a boat, and how it affects the behavior of the vessel.
Keel — what is it?
A keel is a beam connected to the hull of a yacht that runs from the bow to its stern. It is located at the bottom of the boat and is in direct contact with the water. Its main function is to stabilize the vessel, improve its nautical properties and increase the structural strength of the hull.
What materials is a yacht keel made of?
The yacht’s keel is made of materials with exorbitant parameters when it comes to strength. Materials used in its production include:
- steel or cast iron — they provide optimal ballast and resistance to damage,
- lead — its use lowers the yacht’s center of gravity and improves its stability,
- composites — lighter materials are used in advanced, modern designs, sometimes in combination with lead ballast.
Yacht keel — features
The keel’s tasks are:
- course stabilization — it acts as a counterbalance to lateral forces caused by the wind. This prevents excessive lateral drift and helps maintain course even in windy weather on the sea or lake;
- reduction of heeling — the keel has a stabilizing function, reducing the heeling of the vessel under the influence of wind and waves. The weight of the ballast placed in the keel lowers the center of gravity of the yacht, which increases its stability;
- structural support — the keel is an integral part of the hull structure, reinforcing it and contributing to its rigidity and solidity;
- optimized performance — the keel can be optimized for hydrodynamics to reduce water resistance and increase boat speed.
Types of keels in boats
There are different types of keels, which are selected depending on the purpose and design of the yacht.
Fixed keel (traditional)
Fixed keel is the most common type of this structural element. It is an integral part of the hull permanently attached to its lower part. It contains no moving components, which distinguishes it from swing or lift keel.
Swing keel
A swing keel is a type of keel equipped with a mechanism that allows it to change its position in the vertical plane.
Its mechanism of operation is based on a pivot or guide system. Swing keel operation can be manual (using capstans) or automated. It is then based on hydraulic or electric systems. The swing keel is mainly used in yachts that require a different level of draft — sailing in shallow waters.
Lifting keel
A lifting keel is a mechanism by which the depth of immersion can be adjusted. Thanks to this solution, the yacht can sail both deep and shallow waters. The lifting keel makes it easy to transport the yacht on the trailer and launch it from the slip.
An example of a yacht equipped with such a mechanism is the N Fun 30. It has a heavy bulb keel which is raised hydraulically with a pump. In the lowered position, it provides stability and optimal nautical characteristics, while in the raised position it reduces draft and makes it easier to enter ports or navigate shallower water channels or lakes.
The lifting keel is lowered under the pressure of its own weight. The speed of this process can be reduced via a valve that restricts the flow of hydraulic fluid.
False keels
These are additional, usually smaller hydrodynamic components. They improve the nautical properties and stability of the ship and its maneuverability.
False keels are fixed and flat fins. They protrude from the hull toward the bottom of the body of water. A hinged rudder can be attached to their underside. False keels are used in boats with narrow and deep hulls. They are installed to improve the performance of a given vessel in harsh conditions, among other things.
Bulb keel
A bulb keel is a type of keel used in the construction of yachts and other vessels, which is equipped with an additional “bulb” shaped widening at its lower end.
The bulb acts as ballast and lowers the yacht’s center of gravity and increases its stability. It is used in both racing yachts and those designed for marine tourism. They are used in large and shallow yachts with a fairly flat bottom. Bulb keels allow yachts to combine stability with maximum hydrodynamic performance.
Scheel keel
The Scheel keel was invented by the American engineer of the same name. It provides additional lift by changing the appearance at the tip of the keel. Its bulb is flatter. This type of keel usually appears in racing yacht designs.
Deep fin keel
Deep fin keels are not integrated into the hull, they are bolted to it. This type of ballast is much better for upwind sailing, as it provides more buoyancy.
Each vessel (even if the drift is only a few degrees) creates an angle of attack between the fin keels and the surrounding water when sailing upwind. Like a sail or an airplane wing, this structural element generates a low-pressure area on one side and a high-pressure area on the other. The fin keel can move in a lower pressure zone, so the drift is effectively reduced and the yacht moves to windward.
The keel of the yacht — things to remember!
The yacht’s keel affects the safety and maneuverability of the boat. The primary function of this element is to guarantee the stability of the vessel and to prevent it from tilting heavily. This helps maintain the course, especially in high winds and during more difficult weather conditions. The keel also serves a ballasting function. It lowers the yacht’s center of gravity, which is particularly important for racing and performance vessels. Therefore, choosing a boat with the right keel will affect the comfort of steering it and the vessel’s behavior on the water.
