Marine buoys are of the utmost importance in maritime navigation. Their presence ensures ships’ safe passage. Despite their value, many people don’t understand the basics of marine buoys. This is because buoys have many types, which cause confusion.
Some of them are used at a trim level to navigate small boats. On the flip side, some large buoys help maneuver the large vessels. Buoy selection depends on the needs. In this article, I’ll explain the purpose of buoys. You’ll also learn a few essential basics that can significantly impact buoy selection and use. So, let’s get started!
Overview of Marine Buoys
Marine buoys are floating devices installed in water bodies. They can be used at sea level and in river water. Their purpose is to show boats and vessels safe passage or channels in water. Remember, different buoys are available, and their purpose and work vary.
Have you heard of navigational or mooring buoys? Navigational ones help in navigating the ships in safe ways. The mooring buoys help keep the vessel in place. Just like that, there are many other types of buoys. Each of those buoys has its properties and characteristics.
Remember, buoys float at the water body’s surface, but they remain attached to the seabed or riverbed with an anchor and chain. The anchor’s weight does not move the buoys, keeping them in one place. Ships and boats can be anchored with these buoys and stay in one place.
You might get confused by a subtype of buoy known as boating buoys. These are also smaller-sized marine buoys. Their purpose is to navigate small boats in the water that may be unsafe for traveling. These boating buoys have many types, which we covered in the previous article.
6 Basics of Marine Buoys
Have you understood marine buoys? Let’s discuss some basic things related to them. This will help you better understand and choose the right buoys for your needs.
1- Materials of Buoys
Different materials are available for making buoys. However, the performance of each material varies. As you know, buoys remain in the water most of the time, demanding excellent durability and ruggedness to stay in good condition. Common materials include metals, plastics, and foam.
I don’t like metal as a buoy-making material. Why? It gets rusty when it remains in salty water for a long time. Plastics and foam offer exceptional performance and durability, making them stand out. Plastics can make buoys for many years if they remain safe from UV rays.
Manufacturers generally use High-density polyethylene (HDPE) plastics in buoys. It keeps the buoys lightweight yet very durable. However, foam is the ultimate solution for creating buoys. The question is: are foam-made buoys made of 100% foam? The answer is NO!
These buoys have an outer sheath of copper or metal. Inside, the cover and foam are filled. In simple terms, such buoys are known as Foam-filled Buoys. The significant advantage of foam-filled buoys is that their buoyancy is excellent. Even if the buoy is somewhat damaged, foam keeps it floating. Three main types of foams are used in such buoys.
Here is a table showing the difference between these foams:
| Factor | Polyurethane Foam | Copolymer Foam | Syntactic Foam |
| Cost | Low | Medium | High |
| Depth Suitability | Shallow (<1m) | Up to 600 meters | Deep (>600 meters) |
| Water Absorption | High (requires complete isolation). | Moderate (closed-cell foam, some water resistance). | Very low |
| Durata | Low | Moderate (may deform under prolonged pressure). | Very high |
| Applicazioni | Surface buoys, shallow water markers. | Mid-depth temporary applications. | Deep-sea equipment, riser buoys, long-term use. |
2- Buoyancy and Anchoring
Buoyancy indicates the floating nature of buoys. As I said earlier, all types of buoys are very lightweight and can easily stay on the surface of a water body. Even those buoys having outer covers made of metal also show decent buoyancy. If buoys don’t float, they are of no use. Remember, they help navigate by staying at the surface.
Have you ever seen a buoy staying in one place? They are lightweight and have buoyancy. Why do they not float and leave their position? That’s because of anchoring. Buoys consist of anchors, just like ships consist of anchors. Ships drop their anchor in water when they need to stay in one position.
The anchor is heavyweight and keeps the ship from drifting, right? The marine buoys are also attached to similar anchors. The buoy is connected to an anchor through chains. The anchor’s weight ensures buoys don’t drip away when the weather is terrible. If there is no anchor, tidal waves would displace those buoys.
3- Structure of Buoys
The shape of buoys can vary from one type to another. Remember, both shape and size have nothing to do with their basic structure. Buoys with tiny or more significant sizes will have the same basic structure. Let’s discuss the key components that make the structure of buoys.
- Body: This is the primary component of the buoy that supports its buoyancy. Some buoys consist of foam in their cores. But that is not always the case, as some buoys don’t use foam in their core. The outer shield or covering then covers it.
- Hull or Outer Shell: The outer layer or cover protects the buoy’s body. This hull is generally made of robust, durable material. Such material can easily bear the shocks and are resistant to wear and tear. Generally, metal such as aluminum or plastic is used to make this outer shell.
- Reinforcing mesh: Reinforced mesh is added between the core and outer shell. It has no connection with the foam present inside the core of the buoy. This reinforced mesh aims to increase the strength of the buoys. Some buoys also consist of pads that enhance shock absorption.
- Ballast: Stability is a crucial parameter when it comes to buoys. If the buoy is unstable, it may not serve its purpose effectively. Ballast is the weightage point present at the bottom of buoys. It puts weight and keeps the buoy very stable at its point. Generally, metal is used to make this ballast.
- Mooring System: Buoys consist of mooring systems to keep ships in one place. As I said earlier, an anchor keeps a buoy at one point. This buoy is connected with an anchor through chains. So, it remains stable. Ships can be attached with buoys as they do not move due to their anchoring system.
4- Signals & Sensors of Buoys
In the past, buoys had limited features. However, things have changed, and buoys are now equipped with modern technology. The signals and sensors on the buoys collect data on the water bodies. The sensors keep the operator tracking water movement, salinity, and temperature.
Sensors and radar are also critical in the marine world. They help other ships and vessels know the location of these buoys. Remember, these buoys cannot be seen if the boats are far away. So, signals sent from the buoys help ships find these buoys. The radar of these buoys helps detect other ships in the sea.
Another critical parameter is marking and colors. Remember, buoys are marked with specific numbers and colored with different paints. These markings of the buoys convey meaningful information to boaters and other ship captains. You should read our article about the meaning of different buoys that we’ve already written.
5- Buoy Clamping System
A buoy clamping system helps in installing the buoy at any structure. It also helps when you attach an anchor to the buoy. Installing a buoy at any location requires a strong connection with the structure. In such cases, clamping systems come in handy. It consists of clamps, fasteners, or brackets.
The clamp and fasteners ensure that the buoy doesn’t show instability. Remember, these claiming units are made with strong materials such as stainless steel. So, their chances of getting rusty are very minimal. Moreover, the workers take care of these clamps to ensure they remain in good shape for long.
6- Buoy Level Gauge
A buoy level gauge is used to check the water level. As I said earlier, modern buoys collect data about water bodies, making them very useful and profitable. Understanding the water depth, change in depth, speed, and tidal movement is crucial. It helps monitor stations, keep the ships and vessels in safe water, and prevent accidents.
But the question is, how does this gauge system work? Gauges consist of sensors that move up and down according to the rise and fall of water. By tracking the movement of this sensor, operators easily check the water depth. They can also accurately determine the change in water depth over time.
Conclusione
There is no doubt that marine buoys are a great invention. In the past, their role and functionality were minimal. People used to use wood-made buoys to identify safe or unsafe water passages. However, innovation has taken over, and buoys have undergone significant changes with time.
Now, buoys with many sensors, radars, and markings are available in the market. Their usage has made marine traveling a lot easier. The boaters and ship captains easily understand the meaning of buoys and maneuver their ships accordingly. In this article, I’ve explained all the basics of buoys.