The detailed technical drawings of all the typical sizes of Donut Buoys, followed by data tables with weights, sizes, and other details.
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Modular
Anchor-Pendant Buoys, better known as “Donut Buoys” due to their shape, are a
specialized rotating steel core buoys with two or four modules attached to the
sides.
Their rotating steel core
is surrounded by specialized polyethylene foam, and covered with a soft skin
that brings them resistance to impacts, sudden movements, and makes them
suitable for harsher environments.
Donut Buoys are a type of heavy duty support buoy, connected to a segment of a mooring line, typically on offshore or deep water environments.
NOTE: Weight in kg. Measurements in mm.
These are our standard dimensions, after product customization deviation margins might apply.
Data Buoys can be built in sizes as small as 20 kgs of Buoyancy. Our standard sizes start at 1 ton of buoyancy, and up to 2.2 Tons of buoyancy for the Offshore applications in industries such as the Oil & Gas, or even Offshore Wind. These buoys are between 1.5 and 2.3 meters, they are large, stable, and allow heavy instrumentation to reliably be installed on top, with accessories such as solar panels, processing units, and anything that the customer decides to install on their large surfaces. Smaller and larger sizes are available upon request without inconvenience, as we are specialized not only on standard sizes, but also on custom sizes.
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Our Medium sizes start at 16 Tons, achieved with simply two modules of 3 meters each, and can range up to 34 Tons of Net Buoyancy, using four modules of 3.2 meters each. These sizes are commonly used on pipeline deployment (also referred to as pipe-laying), and other sorts of installation support and even recovery operations. Their rotative core offers a degree of stability, even on harsher environments with waves and currents, which is one of the characteristics that makes them so desirable for use in the offshore industry, especially on the Oil & Gas environments during project construction and installation.
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These are our most commonly used Donut Buoys for offshore anchor handling operations. The simple version with two modules of 3.2 m in diameter starts providing 23 Tons of Net Buoyancy, with the complete Four Modules model providing up to 46 Tons of Net Buoyancy, fit for the heaviest applications in the Offshore Oil & Gas and Offshore Wind Industry. They are our largest standard size, but not the largest available, as we are capable of offering even larger sizes on request without any problem, simply let us know your project details and technical requirements.
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Offshore Industry Compliance:
"Donut" Buoys are primarily used in the Offshore Oil & Gas industries, where extensive testing and certification is expected. Osaka Industry provides true End to End Certification, where every step from Design to Materials and Manufacture is carefully controlled, results are evaluated and reported, the customer has control over every stage, and a final and complete certification is delivered. Every batch of Donut Buoys is tested and inspected at professional independent testing facilities, with proper laboratory-grade equipment, and verifies the quality of our buoys independently. Furthermore, donut buoy design, components, materials and methods of manufacture are not only made to fully meet the standard requirements for use in the Offshore, but also made to meet any additional requirements from our customers for their specific projects.
ISO 9001:2015 Quality Assurance:
Quality Assurance and Certification undergoes strict control from our management at Osaka Industry, as we fully meet the requirements stated in ISO 9001:2015 for Quality Management Systems. This is a fairly common standard among suppliers and manufacturers, but Osaka is proud to state it as it is fundamental for ensuring a consistent quality in production, and it enables us to manufacture a buoy in our home country, ship it to our customer, and it can be used in Europe, America, Asia, or anywhere else in the world because its quality is consistent and its properties are accurately measured.
quality@osakaindustry.com
Adjusting Standard Donut Buoys:
Our standard sizes of Anchor Pendant Donut Buoys can be delivered "As is" or can be customized to achieve a proper fit for your offshore project. Donut buoys are composed by modules, each of which can be adjusted in length and in diameter, which therefore alter their buoyancy. The number of in-between sizes is virtually infinite, plus, we are able to offer sizes smaller than the smallest, and larger than our largest standard size. These modifications despite being fairly simple and routinary, make a considerable impact on the suitability for the offshore mooring line they are supporting, as it provides the engineers with total control over the buoyancy, and a higher degree of certainty on the behavior of the complete structure on any planned conditions.
Purchasing Custom Donut Buoyancy:
Offshore industry is regulatory heavy, especially in Europe and America. Besides offering tailored sizes, at Osaka Industry we work with custom foams, materials and coatings, that ensure that our buoys delivered comply with your customer requirements, such as environmental regulations and eco-friendlier materials or other means to reduce carbon footprint and achieve CO2 neutrality, extended life-span for Long Term Mooring projects, special reflective colors for enhanced visibility even at night combined with extreme weather, or even offshore decommissioning friendly design that accounts for the entire product life cycle.
Know What to Avoid:
Since there is no ISO or equivalent standard for the design or manufacture of Donut Buoys, neither exist class certificates for them, it is fundamental to compare the quality of the products from different suppliers, just like you would compare their prices. Donut Buoys are part of a larger, more complex and expensive structure, Offshore Moorings, where a critical failure can cost over 100.000 times the value of the buoys itself, cause human accidents, or even death. Osaka Industry warns against quality claims that are not backed by explicit and objective evidence. At Osaka, for example, we have a detailed dataset with all our batches produced, the details of every project and the requirements from every customer, as well as our results. This dataset is not only hard earned collective experience, but it is a crucial part of our decision-making process, and makes solutions objective and verifiable. For choosing a decent quality donut buoy the most important is to judge the explicit statements and hard evidence over a pretty stock photo, or over a famous brand that isn't backing their products with explicit statements, objective data, and most important of all lack of explicitly mentioned sufficient certification for the Offshore Oil & Gas industry. Otherwise there is a risk over the control of the quality of the products purchased, or might even be harmful for the environment if its certification does not explicitly mention that it covers the materials ends or their finishings. These are crucial aspects to verify before decision making.
technical@osakaindustry.com
Superior quality Donut Buoys are designed to achieve a long life span, withstand the harsher weather conditions in the Offshore, with minimum maintenance and inspection. Their specialized design is backed by superior quality materials. While no ISO standard exists for Donut Buoys, we manufacture them with materials that are ISO or ASTM regulated, with existing verifiable standards, that allow our buoys to be of a consistent quality. The quality of our buoys is verifiable, as it meets the requirements of the US Coastguard, one of the strictest sets of requirements in the maritime industry.
Rigid Internal Core:
The core of the donut buoys is the component withstanding the force generated by the buoyancy opposing the weight of the mooring line that the buoy is supporting. Structural integrity of the core is critical, which is why it is made with a high grade steel rod, that is extremely rigid, able to withstand effort and mechanical stress in the offshore. The core is at the same time rotative, as it allows the connection with the main mooring line to be stable even during harsh weather with strong waves and variable conditions, reducing the exposure of the main components from such harsh conditions. While this rotative property is fairly standard in donut buoys, it is our rigid rod design that prevents bending, which blocks the rod and prevents it from spinning, a failure that tends to occur only during the most extreme conditions, which is precisely where the rotative core capabilities are needed the most.
Enclosed Foam Core:
Enclosed around the steel core is the rigid foam core, it is extremely buoyant, and serves as an enclosure that sets the rotative steel core in place. Its rigid design allows the buoy to withstand compressions without damaging the steel core. This component is 100% enclosed, as it is molded directly into the outer part of the core, which prevents water from interfering with the buoy.
Bonding Foam Layer:
Instead of placing the outer skin directly over the foam core, we decided to include an intermediate layer of a more flexible foam that bonds the two together. This bonding foam is flexible instead of rigid, and is chosen because it has excellent impact absorption capabilities, similar to how a Foam-Filled Fender is constructed, which further protects the donut buoy in extreme conditions in the offshore. This bond is stronger than the foam itself, achieving a buoy construction that prevents it from laminating under stress or impacts, even with an Offshore Service Vessel (OSV), which is an achievement that we are very proud of.
Outer Soft Skin:
The Soft Skin is the ultimate layer of protection and durability for the buoy. We would not call its design "Superior" without the Soft Skin layer. While normal buoy layers are rather rigid or tough, our Soft Skin is elastic and flexible, it does not crack like a normal buoy skin. It is UV resistant and non-marking. It withstands polluted environments such as waters with toxic spillage. This is achieved with a combination of super-resistant nylon cord reinforced filaments wounded in a helix pattern around the entire buoy body, finished with a special coating similar to those of the aforementioned foam-filled fenders. The buoy is constructed to last, and withstand the extreme.
technical@osakaindustry.com
