SEAWARD SEA CUSHION MARINE FENDERS TECHNICAL MANUAL

Transcription

1 SEAWARD SEA CUSHION MARINE FENDERS TECHNICAL MANUAL

2 Offshore California, USA: Tanker Lightering

3 Fender installation: General Cargo Berth SEA CUSHION MARINE FENDER TECHNICAL MANUAL

4 Fender installation: Norway: Fendering of moored LNG carriers SEA CUSHION MARINE FENDER TECHNICAL MANUAL

5 1. Introduction Originally introduced in 1974 as the world's first foam filled marine fender, the SEA CUSHION Marine Fender sets the standard in the industry for high performance and reliability. SEA CUSHION Fenders are now in use on every continent and in over eighty countries worldwide. Applications include tanker lightering; offshore oil, shipyard use and dock operations; and military use. The resilient foam-filled construction provides an unsinkable fender body that permits high energy absorption with a relatively low reaction force compared to most other fendering systems. The SEA CUSHION Fender of today retains much the same outward appearance as the original, but the similarity ends there. Today s SEA CUSHION Fender is the result of significant changes to the original design. The Standard version offers 40 % more capacity through upgraded energy-absorbing closed-cell foam, and the chain and tire nets have been upgraded as well, consistent with this increased capacity. Low Reaction and High Capacity foams are also available, in addition to Standard foam. An Offshore SEA CUSHION Fender is also available, featuring an even thicker outside skin than the already rugged Standard Model. The SEA CUSHION Fender combines quality assurance standards with new elastomer technologies, making it the answer to many specialized fendering requirements. Its urethane skin is unique in that it is reinforced with nylon, which is wrapped in an overlapping helical pattern and integrated within the skin itself. This reinforcement technique gives the SEA CUSHION fender's skin a tear strength up to six times greater than an unreinforced skin. Available in a wide variety of diameters and lengths, from the 3 ft x 6 ft (0.9 m x 1.8 m) size to the supertanker-scaled 14 ft x 28 ft (4.3 m x 8.5 m) size, all Seaward fenders meet the operational performance expectations the industry has grown to depend on. SEA CUSHION fenders are manufactured exclusively by Seaward International, Inc. a worldwide leader in innovative uses of plastics and elastomer technology. Seaward International is a recipient of the President s Export E Award for excellence in exporting fenders and related products. Seaward continues to develop and supply the marine technologies that keep you on course. Contact Seaward s technical staff to help solve your fendering needs through the time-tested applications of Seaward's marine fenders. Fender installation: Missouri, USA: Tank barge SEA CUSHION is a registered trademark of Seaward International, Inc

6 Fender installation: Gulf of Mexico, USA: Tanker lightering (photo courtesy of Arco Marine, Inc.) 2 SEA CUSHION MARINE FENDER TECHNICAL MANUAL

7 2. Features and Advantages Seaward SEA CUSHION Fenders feature a design proven through testing and service to provide the best performance for today's demanding marine operations. The unique SEA CUSHION Fender construction provides a number of features and advantages not found in other fenders. 2.1 LOW REACTION FORCE SEA CUSHION fenders are soft fenders; i.e., they have a low reaction force and low reaction pressure (only 3.6 kip/ft 2, or 17.6 ton/m 2 ). The reaction force is lower for smaller vessels or more gentle berthing, unlike stiff rubber buckling element fenders, which impart the same high load for all types of berthings and vessel sizes. 2.2 HIGH ENERGY ABSORPTION The SEA CUSHION Fender has the highest energy absorption for its size of any fender available (up to 90 % greater than a 0.5 kg/cm 2 pneumatic fender). Even higher energy absorption is available with High Capacity foam, for specialized situations. 2.3 LARGE STANDOFF DISTANCE Standoff distances up to 16 feet (4.9 m) can be achieved with the SEA CUSHION Fender. Unlike rubber buckling element fenders, the SEA CUSHION Fender maintains its standoff even under constant loads due to winds or currents. 2.4 EASY INSTALLATION SEA CUSHION Fenders are mounted with standard components, such as wire rope, chain, swivels, and shackles, available from Seaward. Dockplates are also available for use in ship-to-dock applications. No complex attachments are required, and SEA CUSHION fenders can be easily relocated. 2.5 ADJUSTS TO WATER LEVEL When used in the floating mode, the SEA CUSHION Fender rises and falls with the water elevation. This makes it an excellent choice for areas with high tides or rivers with high seasonal water level changes. Above shows three stages of compression of SEA CUSHION Marine Fenders, from 0 % in the top photo, 20 % in the middle photo and 80 % compression in the bottom photo. Actual working compression, however, should not exceed 60 % compression

8 2.6 LOW MAINTENANCE SEA CUSHION Fenders have no safety valves or air pressure to maintain. The chain and tire net components have been designed for a long life with minimum maintenance. 2.7 COST EFFECTIVE, LONG SERVICE LIFE SEA CUSHION Fenders are unimpaired by seawater, sunlight, or oils. They are unsinkable and continue to perform even if punctured, unlike pneumatic fenders. The SEA CUSHION fender can work in virtually all environments, including rough seas and against abrasive surfaces. 2.8 QUALITY Seaward s quality system incorporates a fully documented inspection system that meets U.S. Government requirements, including a calibration system in accordance with ANSI/NCSL Z540 (ISO ). Materials testing, verification and inspection are in accordance with the standards and practices of: ASTM (American Society for Testing and Materials) ISO (International Organization for Standardization) AWS (American Welding Society) AISC (American Institute of Steel Construction) SSPC (Steel Structures Painting Council) Statistical techniques include statistical process control and sampling plans. Seaward s quality system has been audited and approved by the following U.S. Government organizations: ABS (American Bureau of Shipping system and type approvals) DCMC (Defense Contract Management Command formerly DCAS) DGSC (Defense General Supply Center Quality Vendor Awards) 2.9 PROVEN TRACK RECORD SEA CUSHION Fenders have proven their performance through extensive testing and in-service use for over 25 years. Their rugged design has been continually improved and upgraded over this period. The most recent design upgrades have been tested using the international PIANC test methods, and the fender ratings reflect these standards. Today the SEA CUSHION Fender is unequalled in performance and reliability. Fender installation: Port of New Orleans, Louisiana, USA: Fendering of Cruise Ships 4 SEA CUSHION MARINE FENDER TECHNICAL MANUAL

9 3. Construction Features Chain and Tire net Nylon filament reinforced elastomer skin Closed-cell flexible foam SEA CUSHION Fenders incorporate a number of construction features that make them unique compared to other types of marine fenders. 3.1 FOAM-FILLED CONSTRUCTION The interior of the SEA CUSHION Fender is completely filled with a resilient closed-cell foam, which has been specially formulated for maximum impact energy absorption. The use of this foam-filled construction process makes SEA CUSHION fenders unsinkable and allows them to continue to function even if accidentally punctured. Seaward uses a unique process of laminating the foam together with heat into a one-piece integral construction. This process produces a durable product that retains its energy absorbing capacity even after years of service. In operation, SEA CUSHION Fenders absorb energy by compression of the many tiny closed cells within the foam interior. The walls of these miniature cells contain the pressure of compression. Because of the strength of the many cell walls throughout the foam, the pressure buildup at a point of compression is not transmitted significantly to other parts of the foam, and the exterior skin is not required to act as a pressure containment membrane. SEA CUSHION Fenders are normally supplied with Standard Foam, which is preferable for most applications. However, Low Reaction Foam (having 60 % the Reaction Force and Energy Absorption of Standard Foam) is available for situations requiring very low hull pressures (approximately 2.2 kip/ft 2 or 10.8 tom/m 2 ). Also, High Capacity Foam is available for situations where more energy absorption is required for a given fender size. High Capacity Foam has 130 % the Reaction Force and Energy Absorption of Standard Foam. 3.2 FILAMENT-REINFORCED SKIN The skin of the SEA CUSHION Fender is constructed of a special synthetic elastomer that is reinforced with nylon tire cord filaments. Materials used in the skin are among the most

10 abrasion-resistant and durable materials known. Multiple layers of continuous nylon filament reinforcing are applied by a filament winding machine specifically developed by Seaward International, Inc. for producing high strength reinforced coatings. The filament winding process produces a fender skin that has reinforcing fibers oriented in the optimum direction for maximum strength. This also results in a completely seamless outer coating. Due to the continuous filament winding, local loadings are distributed over a wide area of fender surface, minimizing stresses in the fender skin and increasing its tensile strength. Also, there are no stress concentrations caused by metal fittings in the skin, because such fittings do not exist in a SEA CUSHION Fender. Most SEA CUSHION Fenders are supplied with a Standard skin thickness, which has been proven effective for use in normal marine operations over its 25-year history. However, SEA CUSHION Fenders can also be supplied with an increased skin thickness, such as that supplied in the Offshore SEA CUSHION style. Specifications for skin thickness of the Standard and Offshore style SEA CUSHION fender are given in section EXTERNAL CHAIN AND TIRE NET SEA CUSHION Fenders employ an external net for carrying the tensile loads imposed on the fenders, and for handling and making attachments to the fenders. This design minimizes stresses in the fender skin, since the tensile loads are carried by the external net. Also, since no rigid strength member is used inside the fender itself, SEA CUSHION Fenders are capable of both longitudinal and angular compression. The chain and tire net design uses heavy galvanized chain, fitted with heavy tires (normally aircraft tires) at the net intersections. The advantages of the chain net are the ease of repair of individual segments of the net and the good corrosion resistance of galvanized chain. The longitudinal chains are joined by rugged terminations at both ends of the fender. The tires provide abrasion resistance and additional standoff distance. The chain and tire net configuration for each size of SEA CUSHION Fender (both Standard and Offshore style) is shown in Section 5. 6 SEA CUSHION MARINE FENDER TECHNICAL MANUAL

11 5. Fender Data 5.1 FENDER DATA SUMMARY The following tables summarize the energy absorption, reaction force, and weight of Standard SEA CUSHION Fenders. The first table shows the data for English sizes from 3 ft x 6 ft to 14 ft x 28 ft. The second table shows the data for metric sizes from mm x mm to mm x mm. The values presented in these tables are based on the maximum recommended working compression of 60 %. This compression should not be exceeded. Actual values may vary plus or minus 15 % from stated values due to variations in test conditions and material properties. Tons are metric tons of kg or lb. The energy and reaction force ratings are derived from laboratory tests of fenders of various sizes, using the PIANC test protocols. Energy and force ratings for other sizes of SEA CUSHION fenders are available on request, or may be approximated by interpolation of, or extrapolation from, the data shown. SIZE ENERGY ABSORPTION REACTION FORCE WEIGHT WITH CHAIN DIAMETER x LENGTH AT 60% COMPRESSION AT 60% COMPRESSION AND TIRE NET ft mm ft kip kn m ton m kip kn ton lb kg 3 x x x x x x x x x x x x x x x x x x x x x x x x x x x x SIZE ENERGY ABSORPTION REACTION FORCE WEIGHT WITH CHAIN DIAMETER x LENGTH AT 60% COMPRESSION AT 60% COMPRESSION AND TIRE NET mm ft ft kip kn m ton m kip kn ton lb kg x x x x x x x x x x x x x x x x x x x x x x x x x x x x

12 SEAWARD INTERNATIONAL, INC Martinsburg Pike, P.O. Box 98 Clearbrook, VA USA 1 (800) Phone: (540) Fax: (540)