Generally speaking, the standard pressure range for marine airbags is roughly between 0.1MPa and 0.5MPa, but the specific value needs to be determined based on the actual application scenario and the manufacturer’s technical specifications. Marine airbag is an auxiliary equipment that uses high-pressure gas to generate elastic deformation to carry and move ships, and is widely used in ship launching, shifting, maintenance and other operations.
Ship Launching Airbags
The technical principle is mainly based on the compressibility and elasticity of gases. By injecting a certain pressure of gas, the airbag expands, providing sufficient buoyancy or support force. In terms of application scenarios, the selection of standard pressure for marine airbags needs to consider factors such as the tonnage of the vessel, the size and quantity of airbags, and the operating environment. For example, for small vessels or light operations, the standard pressure of airbags may be relatively low to meet the requirements of economy and safety; For large vessels or heavy operations, it is necessary to choose airbags with higher standard pressure to ensure sufficient load-bearing capacity and stability. In terms of industry standards, the production and use of marine airbags must comply with relevant international and domestic standards, such as ISO, GB, etc. These standards provide clear regulations on the materials, manufacturing processes, performance parameters, and testing methods of airbags to ensure their quality and safety. For example, the standard may specify key indicators such as deformation, compressive strength, and service life of airbags under specific pressures, providing important basis for the design and selection of airbags.
Marine Airbags
In addition, the standard pressure of marine airbags is also affected by manufacturing processes and material properties. Advanced manufacturing processes and high-quality materials can improve the pressure resistance and sealing performance of airbags, allowing for the use of higher standard pressures. Therefore, when choosing marine airbags, in addition to considering their standard pressure, attention should also be paid to their manufacturing process and material quality. When using marine airbags, it is necessary to strictly follow the technical specifications and operating instructions provided by the manufacturer to ensure the safety and effectiveness of the airbags. Especially during the inflation and deflation process, it is necessary to control the rate of pressure change to avoid damage to the airbag due to sudden pressure changes. At the same time, regular inspection and maintenance of airbags are also important measures to ensure their long-term stable operation.
Sea surface buoy is a landmark device floating on the sea surface, mainly used to mark waterways, divide water areas, or mark specific locations, providing spatial reference for ship navigation, marine scientific research, and resource development. Its core function is to continuously transmit position information and reduce navigation risks in complex sea conditions through its striking appearance and stable floating performance. According to different application scenarios, offshore buoys can be divided into waterway buoys, meteorological buoys, scientific research buoys, and other types. Among them, rolling plastic buoys have become a common choice for offshore operations due to their strong weather resistance and low maintenance costs. 1、 Structural Design and Technical Principles: Sea surface buoys usually consist of three parts: the float, the identification system, and the anchoring device. The floating body is formed by rotational molding process, using high-density polyethylene (HDPE) as raw material. The plastic particles are melted and uniformly attached to the inner wall of the mold through high temperature heating, and after cooling, a hollow structure is formed. This process endows the floating body with seamless, impact resistant, and corrosion-resistant characteristics, making it suitable for long-term seawater erosion and ultraviolet radiation. The identification system often uses orange or red high reflective coatings, and some models are equipped with solar LED lights to ensure night visibility; The anchoring device is connected to the sinking block through steel cables or chains to keep the buoy vertically stable and avoid being overturned by wind and waves. 2、 Anti aging and adaptability optimization: In view of the characteristics of high salinity, high humidity and strong ultraviolet ray in the marine environment, the anti oxidant and ultraviolet absorber are added to the materials of the rotomolding buoy to form an anti-aging coating. Experimental data shows that the service life of such buoys in coastal areas can reach more than 10 years, far exceeding traditional metal or wooden buoys. In addition, polyurethane foam can be filled inside the floating body, which can not only increase buoyancy but also prevent water seepage. Even if the outer layer is damaged, it can still remain floating. In terms of color selection, orange and red have the highest contrast in the seawater background, which meets the visual identification standards of the International Association of Navigational Aids (IALA). 3、 Customized applications and operating standards: The cylindrical buoy supports customized design of size, color, and identification system. For example, research buoys can be equipped with sensor modules to monitor real-time data such as water temperature, salinity, and wave height; Channel buoys can adapt to different water depths and flow velocities by adjusting the volume of the float and the weight of the anchor system. Attention should be paid during operation: Before installation, check the sealing of the floating body to avoid transportation damage; The anchor length should be greater than 1.5 times the water depth to prevent the buoy from being dragged and displaced; Regularly clean the surface of the floating object of biological attachment to ensure clear labeling. The customization process usually includes requirement communication, scheme design, mold making, and sample testing, with a cycle of about 15-30 working days. 4、 Spot supply and scene coverage: The standardized buoy inventory specifications are complete, covering the needs of coastal and inland waterways across the country, and can be adapted from shallow water aquaculture areas to deep-sea operation platforms. The spot models mainly have a diameter of 1.2 meters to 3 meters, a buoyancy range of 500kg to 3 tons, and support 24-hour technical consultation. For special scenarios such as polar expeditions or areas with frequent typhoons, reinforced buoys can be customized to enhance their resistance to wind and waves by increasing the thickness of the float wall and anchor strength. Its self operated model ensures full process quality control from design to after-sales, reducing communication costs caused by intermediate links.
Unless otherwise specified, tests shall be performed under the following conditions:
a) ambient temperature: 10 degree ~35 degree
b) media: (1) dry clean compressed air, and (2) clean fresh water for bursting test.
Testing instruments, including pressure gauages and testing machine, shall be calibrated.
The test shall be performed using a full-sized air bag. If the air bag is too large to be mounted on the test machine, the test may be performed on a scaled-down air bag. In order to maintain a proper representation of the full-sized sample airbag, the diameter of the scaled-down air bag shall be no less than 1/2 of the full-sized sample air bag diameter while the length (L) shall be no less than 3 times the diameter of the scaled-down air bag.
Compression Test
Compression test under the initial internal pressure specified in Table 3 should be carried out after the tests of 5.1, 5.2, 5.3 and 6.3
The air bag is to be put on a press with large enough width and length to ensure that all parts of the compressed air bag is within the press. The test should be conducted as follows:
a) fill the air bag to the initial pressure in Table 3, start the test machine and press the air bag perpendicularly till the percentage deformation reaches 70%. Observe to see if the air bag is functioning properly;
b) gradually reduce the compressive force on the air bag until the air bag, by its own flexibility, returns to the height of its original state. Record the internal pressure;
c) apply a compressive force perpendicularly to the air bag again, till the percentage deformation reaches 70%
During the course of compressing and releasing, the reaction forces, internal pressures and deformation rate should be recorded at every 10% deformation interval.
The compression performance curve of a QG6 air bag is shown in Figure A.1. The rated working pressure of the air bag is as specified in Table 3.
Ship Launching Airbags are also referred to Marine Airbags, which is a ship operation equipment made of high-strength rubber and synthetic fiber, featuring a reinforced layer of fabric and wear-resistant rubber structure. It includes an inflation valve and a tow-end assembly, generating buoyancy to support the ship’s weight through inflation. Its production complies with the JT/T 302-1996 “Technical Specification for Marine Airbags,” and has obtained international certifications such as from China Classification Society and French Bureau Veritas. It is primarily used in scenarios like ship launching, caisson transportation, and heavy cargo handling, capable of withstanding the launching pressure of vessels with a deadweight tonnage of 100,000 tons. The burst pressure exceeds industry standards, and the air tightness pressure loss is less than 3% within 24 hours.
What is bearing capacity of air bag?
It is maximum load carrying capacity of the air bag, while it suffers no permanent deformation or damage
What is body of air bag?
It is cylindrical part of the air bag after being fully inflated with compressed air
What is burst pressure?
It is internal pressure at which the air bag bursts
What is diameters of air bag?
It is diameter of the air bag body
What is head of air bag?
It is conical parts connecting the body and the mouth of the air bag
What is initial internal pressure?
It is air pressure that fully inflates the air bag, before compression
What is length of air bag?
It is lenght of the air bag body
What is mouth of air bag?
It is metal valves mounted on both ends of the air bag for charging air
What is percentage of deformation?
It is ratio of the deformed height to the original diameter of the air bag while the air bag is being compresssed
P= (D-H)/D
Where
P is the percentage deformation(%)
is the original diameter of the air bag (%)
H is the height of the compressed air bag (m)
What is rated working pressure?
It is maximum allowable internal pressure of the air bag while supporting a weight or load equal to the rated bearing capacity of the air bag
What is Synthetic-tire-cord layers?
It is reinforced layer of the air bag which is made of rubber coated synthetic-tire-cord fabrics
What is total length of air bag?
It is overall length of the air bag
What is the type and model of air bags?
Marine air bags are categorized by the following two types according to the bearing capacity, per meter in lenght:
a) QP – ordinary air bag’
b) QG – high-bearing capacity air bag
What is the size of ship launching airbags?
Diameters of air bag (d) varies such as 0.8m, 1.0m, 1.2m, 1.5m and 1.8m, etc.
Length of air bag (L) is to be specified by the user.
Foam filled fender, also known as solid polyurethane fender, is a floating fender system made of foamed polyurethane, foamed EVA, or foamed rubber, primarily used for ship-to-berth protection in scenarios such as ports, docks, offshore oil platforms, and ship-to-ship operations. This product employs lightweight, high-elasticity foam as the cushioning medium, with closed-cell foamed material internally and polyurethane elastomer externally sprayed to enhance corrosion resistance. The fender has floating properties, allowing installation positions unrestricted by tidal fluctuations, and is secured via chain suspension. It exhibits significant reaction force variation at 60% compression with high energy absorption efficiency, a service life of 10-15 years, and features high strength, strong adhesion, maintenance-free operation, acid and alkali resistance, and anti-permeability. Product specifications range from 0.5 to 3.3 meters in diameter, with non-standard sizes available for customization, and exterior colors adjustable to meet identification requirements. Some models have received international certifications such as those from the China Classification Society and the French Classification Society.Foam Filled Fenders are versatile, robust and suitable for almost all applications. The performance of foam filled fenders can be modified to meet the specific specification requirements, its manufacturing process allows for virtually any size of fender to be constructed selecting the appropriate grade of foam core and elastomeric skin.
Foam Filled Fenders share a construction technology centered on a closed-cell polyurethane foam core and an outer skin of reinforced polyurethane elastomer. The closed-cell foam structure retains performance even if a fender’s skin is punctured. The closed-cell internal structure prevents water from ingressing into the foam.
The polyurethane floating fender is a compression-type fender, with a polyurea material serving as the outer protective layer and closed-cell rubber-plastic foam as the cushioning medium. Its interior features a closed-cell polyethylene foam core, and the fender surface is coated with polyurethane elastomer. The foam fender incorporates a spiral reinforcement layer (ZL201120207212.9), with the exterior made of polyurethane elastomer. Based on external assembly, it is categorized into sleeve-type, sleeveless-type, and rotating ear-type. R1: “Foam” must be translated as foam. Foam fenders can absorb impact energy through compressive deformation like a sponge [8]. By compressive deformation, they absorb the impact energy of vessels, thereby reducing damage to docks and ships [12]. When compressed by 60%, the reaction force increases significantly from small to large, and the energy absorption capacity is substantial.
The core of the solid polyurethane fender is made of EPU and a new type of polymer material with adjustable high elastic modulus. The internal buffer medium is high-density closed cell rubber plastic foaming material, such as polyethylene or EVA foam. Some products use 100% closed cell EVA foam hot lamination technology, which does not use adhesives. To enhance toughness and puncture resistance, some fenders use spiral wound embedded nylon tire cords or spiral reinforcement layers inside. The external protective layer is formed by spraying polyurethane or polyurea elastomer onto the surface using high-pressure airless spraying equipment. After manufacturing, the fender needs to undergo inspection and pressure testing to ensure compliance with relevant standards.
What is Foam Filled Fenders Classification?
The classification of foam fenders includes polyurethane foam fenders, floating fenders, etc. The interior of polyurethane foam fender is EVA elastic foam body. After adding cord layer in the middle, polyurethane polyurea is sprayed on the exterior to protect the middle core body. The outer protective layer of the floating rubber foam fender is a rubber layer, which is wrapped in the foam core to form a protective sleeve through high-temperature vulcanization.
What is Foam Filled Marine Fenders Performance?
The foam filled fender is made of closed-cell foam material, capable of absorbing 1.2-1.5 times the energy of an inflatable fender, effectively dissipating impact energy during compression. Its reaction force coefficient can be as low as 40-60 kN/m, approximately 30% lower than the traditional DA-type rubber fender’s 60-80 kN/m, helping to reduce hull stress and dock damage risks. The closed-cell foam structure evenly distributes stress under compression, preventing localized stress concentration. The outer surface of the fender is protected with a polyurethane elastomer layer, offering strong resistance to seawater corrosion and a service life of up to 15 years. The standard design lifespan is typically 10-15 years, while some products can last 15-30 years under suitable conditions. These products require no regular inflation checks, pose no risk of leakage, and demand minimal maintenance. The weight of the fender is reduced by 60%-70% compared to steel fenders of the same specifications, making it lighter and facilitating handling and installation. It possesses self-floating capability, allowing automatic position adjustment with tidal water levels, and installation is not restricted by tidal variations. As a solid structure, it eliminates the risk of explosion, and its external protective layer offers scratch and abrasion resistance. R1: “Foam” must be translated as foam. The polyurethane elastomer combines the high strength of plastics and the high elasticity of rubber, exhibiting properties such as wear resistance, oil resistance, acid and alkali resistance, and low-temperature resistance. The internal foam material can be recycled and reused, reducing waste generation.
What is Foam Filled Fenders Advantages?
1. It has floating performance and its installation position is not affected by tidal range 2. No need for inspection during use, no need for inflation, not afraid of scratching, not afraid of friction, resistant to seawater, acid and alkali, with a service life of up to 10-15 years Year, maintenance free 3. There is no danger of explosion and it is safe 4. It has better energy absorption performance and lower reaction force performance. When compressed by 60%, the reaction force decreases from small to large and the energy absorption is extremely high. 5. The product specifications are manufactured according to the needs, with the largest specification in ship fenders 6. The exterior of the fender can be coated with various colors, making the product smooth and beautiful, with clear markings 7. Adopting chain suspension, easy installation and mobility, the chain tire mesh can be freely selected to increase the service life of the fender
What is Foam Fenders Specification and Certification?
The conventional standard size range for solid polyurethane fenders is diameter (D) 0.5 meters to 3.3 meters and length (L) 1.0 meters to 6.5 meters In addition, manufacturers can produce products of unconventional sizes according to customer needs. According to the external assembly method, solid polyurethane fenders are mainly divided into three types: sheathed, unsheathed, and rotating lifting ear. The products of mainstream manufacturers have passed quality certifications from multiple international classification societies, including China Classification Society (CCS), French Classification Society (BV), Det Norske Veritas (DNV), American Bureau of Shipping (ABS), etc. The product performance parameters include specifications (diameter and length), reaction force (tons) and energy absorption (tons · meters) at 60% compression deformation, and body weight (kilograms). The specific values cover a wide range, such as specifications ranging from a diameter of 300 millimeters and a length of 500 millimeters to a diameter of 3000 millimeters and a length of 6000 millimeters, corresponding to a reaction force of 1.5 tons to 160 tons when compressed by 60%, energy absorption ranging from 0.18 tons · m to 114 tons · m, and body weight ranging from 4 kilograms to 1988 kilograms. These parameters are measured based on a static state with a tolerance of ± 10%.
What is Foam Filled Marine Fenders Features?
Wide range of standard and custom sizes
Low reaction and high energy options
Operate floating or suspended
No chain/tyre required
No-marking even against while hulls
Unsinkable design
Widely used in naval application
Since it is not air filled it is virtually maintenance free
What are Foam Filled Fenders Application?
Cruise Ships
Container Vessels
Bulk Cargo
RoRo and Ferries
Oil and Gas Tankers
General Cargo
Navy Berths
Ship-to-ship transfers
What is Foam Fender Effect of Temperature?
Polyolefin foams are used in foam filled fenders. When subjected to high temperatures, these foams can lose some of their compression resistance, and therefore lose some energy absorption capacity. Likwise, when these foams are subjected to low temperatures, they become stiffer and gain energy capacity. This effect is temporary in both cases, if not carried to the extreme.
The graph above shows the effect of temperature on the various types of foam used in foam fenders. The energy absorption is shown relative to the foam in a standard fender compressed at a rate of 2 in/min(51 mm/min) at 75 (24 degree), which is assigned a rating of 100. This does not reflect the performance of the fender as a whole, because other factors come into play in determining the energy absorption capacity, such as skin thickness and the confining effect of the skin on the foam.
However, the general trend will be evident. In general, if a fender will be constantly exposed to elevated temperatures, such as in installations in hot climates, a slightly larger fender size than normal may be recommended.
What is Foam Filled Marine Fenders Effect of Compression Speed?
At a given percent compression, foam compressed at a high strain rate will absorb more energy than foam compressed at a low strain rate. Polyolefin foams compressed at high strain rates are stiffer than when compressed at low strain rates, where strain rate is defined as the fraction of the foam thickness compressed in a given time interval. This trend shows up in fender performance, although other factors come into play in determining fender energy absorption, such as skin thickness, temperature, and the confining effect of the skin on the foam.
Floating pneumatic rubber fender is fender which is made of synthetic-cord-reinforced rubber sheet with compressed air inside to enable it to float on the water and work as a shock absorber between to ships, or between ships and berthing structures when they come alongside each other on the water. This high pressure floating pneumatic rubber fenders have sometimes been colloquially referred to as “Yokohama fenders” or “Yokohama type fenders”.
What is Outer Rubber?
It is rubber layer that covers the outside of the pneumatic fender to protect the cord layers and the inner liner rubber from abrasion and other external forces
What is Inner Rubber?
The liner of rubber membrane that seals the pressurized air inside the fender
What is synthetic-tyre-cord layer for reinforcement
Layer made of synthetic-tyre-cord fabric, which maintains the internal air pressure of the fender. As the main fibres of the synthetic-tyre-cord fabric are not braided like synthetic canvas fabric or synthetic belt fabric, there are advantages for its fatigue-resistanceperformance and pressure-holding performance.
Where is the bead ring?
Steel ring which is placed at one end (or both ends) of the fender and holds the end of cord layers
Where is the flange opening?
Steel flange, which is mounted on the pneumatic rubber fender, to which an air valve or safety valve can be adapted
What is guaranteed energy absorption?
It is energy that the floating pneumatic fenders can absorb without permanent deformation or failure
What is reaction force?
It is force produced by a fender reacting to a compressive force, the reactive force is equal to the force of the air pressure of the fender multiplied by the area of the fender in contact with the ship or berthing structure
What is the initial internal pressure?
It is air pressure at which can uncompressed fender operates
What is endurable pressure?
It is inner pressure at which a fender bursts
What is net-type floating pneumatic fender?
It is fender which is covered by a protection net consisting of either chain, wire or fibre and usually with tyres or rubber sleeves.
What is sling-type pneumatic rubber fender?
It is a fender which is designed to be used without a protection net
What is bearing capacity of air bag?
P= (D-H)/D
Floating pneumatic rubber fender is fender which is made of synthetic-cord-reinforced rubber sheet with compressed air inside to enable it to float on the water and work as a shock absorber between to ships, or between ships and berthing structures when they come alongside each other on the water. This high pressure 
