Are you looking for ship barriers? Bulkheads are an essential part of any ship’s structure and help separate the ship into compartments that are water and fire-resistant. In this article, we will delve into the details of the different types of barriers and their specifications.
To do this, we will explore the various uses of bulkheads, their location on the ship, and the types of construction they use. We will also review the three main fire-resistant classifications according to the International Convention for the Safety of Life at Sea (SOLAS).
After reading this article, yacht engineers will be able to understand the uses of different bulkheads and some details that help differentiate them. Let’s get started.
Uses of Bulkheads on Board
Bulkheads are walls inside a ship’s hull that separate the hull into smaller compartments. These barriers are believed to have appeared on Chinese sailing ships in the 12th century and were widely used by Western navies in the early 19th century.
This barricade serves a variety of purposes:
Enhance the structural integrity of the hull – Dividing the ship into smaller sections helps to increase its strength. Bulkheads also support the deck, making it more durable and resistant to damage.
Controlling flooding in case of damage – Bulkheads can seal and isolate damaged compartments from the rest of the ship. This way, the captain can keep the ship afloat while the rest of the compartments (cargo, accommodation, engine room) remain usable during ship repairs.
Hull divisions for storage and accommodation purposes – Dividing the hull into different sections allows sailors to carry different types of cargo on the same ship. Depending on the type of ship, this section can have different uses. For example, engineers use bulkheads to separate passenger cabins from crew cabins on yachts and merchant ships.
Creating fireproof compartments – Certain types of bulkheads can help control fires on board. Just like flooding in a watertight compartment, we can isolate a fire from the rest of the ship by sealing it with a bulkhead. Additionally, the crew can easily focus on putting out a fire in a specific part of the ship.
We classify barriers based on three main characteristics: purpose, location, and structure. Below, we will discuss each category and its subcategories in detail to provide you with a more comprehensive understanding of all the different types of ship protection.
Types of bulkheads on ships by location
The first classification of bulkheads is based on their location in the ship. There are two main types of ship barriers at each location:
Transverse bulkhead
Transverse bulkheads separate one side of the ship from the other and are usually used to create watertight compartments. They also strengthen the ship’s structure and prevent deformation and bending stresses.
Longitudinal bulkhead
Longitudinal bulkheads extend to the bow and stern of the ship, dividing the hull along its length. Engineers use them within transverse bulkheads to further increase the number of compartments. Therefore, when some compartments are flooded and isolated, the ship can still maintain greater buoyancy.
In addition, these bulkheads are key structural components that enhance the longitudinal safety of the ship. Therefore, they are essential for large ships such as tankers and merchant ships.
Types of Bulkheads Based on Purpose
The second way to classify barriers is based on purpose. Below, we will introduce some of the main types of ship anti-collision devices based on their purpose.
Watertight Barriers
As the name suggests, watertight bulkheads have one main purpose, which is to divide the ship into smaller, more watertight compartments. Depending on the size of the vessel, it can be:
Made from a single sheet, it is suitable for small vessels.
After being reinforced, bulkhead rigidity can be increased for larger vessels. This way, the barrier can withstand the maximum hydrostatic pressure when the compartment is flooded.
After installation, shipyard engineers test watertight bulkheads using pressure hoses to provide sufficient information about possible leaks. Another less invasive method of leak testing is to pressurize the bulkhead chamber with air and check if there is a drop in pressure.
Finally, it is worth noting that watertight bulkheads are usually equipped with watertight doors that allow the crew to move freely within the vessel.
The size of the doors is kept to a minimum, and the openings are tight to maximize the integrity of the barrier.
The size of the door is kept to a minimum to maximize the integrity of the barrier. In addition, the opening is reinforced with additional metal sheets (double plates) to ensure durability around the watertight door.
Non-watertight barriers
Ship manufacturers install non-watertight bulkheads for other types of uses where it is not necessary to isolate the compartment in case of flooding. Their installation divides the existing section into smaller rooms to create a wheelhouse, storage compartments, engine hoods, tool storage rooms, etc.
However, these bulkheads increase the rigidity of the yacht, making it resistant to the deformation forces generated by sailing.
Crash barriers
A crash bulkhead is a type of watertight barrier located in the front of the ship. This part of the ship is particularly durable because, as its name suggests, it limits the damage caused by a full-scale collision with other ships or parts of land. Anchors are usually located in this part of the ship.
To determine the exact location of the crash barrier, engineers must meet the following requirements:
The barrier should not be too far forward to avoid being easily damaged in a head-on collision.
Bulkheads should not be so far back that the vessel creates too much friction with the stern when launching. Apart from the obvious safety issues, this also allows the captain to save fuel when returning to shore when the vessel is damaged.
It should provide maximum cargo space.
More precisely, the crash barrier should be 5% to 8% away from the bow of the ship.
If you are interested in learning more about the additional regulations for crash barriers, watch the video below.
Isolation Barriers
Finally, the last category of ship fenders in terms of usage is the isolation fenders. Fires are a major concern on ships, as they constantly carry large amounts of flammable substances (fuel and oil).
Engineers create these types of barriers to isolate fire-hazard compartments from the rest of the ship. Therefore, bulkheads around fuel tanks and engine rooms must be fire-resistant as per SOLAS fire protection requirements.
Types of Bulkheads on Ships by Construction Method
The final classification of barriers depends on how they are constructed. Based on this feature, there are two main types of ship bulkheads:
Simple Barriers
Simple barriers are easy to identify because they are made of a straight piece of metal. On smaller vessels, such as yachts, simple bulkheads do not require any reinforcement.
On larger vessels, engineers need to reinforce simple bulkheads to provide maximum resistance. To achieve this, they weld or screw stiffeners to the guardrail sheeting.
Corrugated guardrails
Corrugated guardrails are made from corrugated metal sheets. The corrugations are used in engineering to provide natural stiffness to a variety of materials, including cardboard and metal.
Due to this property, engineers do not need to reinforce corrugated guardrails with stiffeners. As a result, these guardrails are lighter and more durable than ordinary guardrails.
Classification of bulkhead types according to fire resistance ratings under the International Convention for the Safety of Life at Sea (SOLAS) Finally, a final classification is given to barriers, covering their insulating properties.
Section A
Section A includes all watertight barriers. To fall into this category, you must meet the following criteria:
- Made of metal and reinforced accordingly.
- Prevents the spread of smoke and flames for the first 60 minutes after a fire breaks out.
- These panels are insulated to prevent heat transfer to the unexposed side for a specified period of time. The temperature should not be higher than the original temperature by an average of 140°C.
- The temperature of the joints should not be higher than the original temperature by an average of 180°C.
- Based on the time frame for which these panels provide insulation, we can classify them into the following subcategories:
- Class A – 60 minutes of insulation.
- Class A – 30 minutes of insulation.
- Class A – 15 minutes of insulation.
Class B Section
Class B panels have the following characteristics:
- Made of non-combustible materials, and all materials used in their construction are likewise non-combustible.
- These panels prevent the spread of flames for the first 30 minutes after a fire breaks out.
- Insulated to prevent heat above 140°C from spreading to the unexposed side.
- The temperature of the joints should not be higher than the original temperature by an average of 225°C.
- Finally, Class C panels are made of fire-resistant materials. However, you do not need to meet additional requirements such as thermal insulation or smoke protection.
In summary
In this article, we discussed the different types of seawalls, how to identify them, and their role on a yacht. In short, we have divided them into three major categories, each with subcategories:
- By location
- Cross
- Linear
- By purpose
- Waterproof
- Non-waterproof
- Anti-collision
- Isolation
- By construction
- Basic
- Corrugated
In addition, we have detailed the different grades of barriers (A, B, C) based on their fire resistance and insulation capabilities. In short, a seawall is an essential component in the construction of any vessel, big or small. It strengthens the vessel and protects against fire and flooding.
