Lifting Chain & Chains for Towing Bridle Arrangements
Lifting chain is designed for use with hoists, cranes, winches, and other material handling equipment. It is also used in rigging slings and for lashing. There are two standard grades for lifting chain: grade 80 lifting chain and grade 100 lifting chain. Other grades of lifting chain may also be available from some suppliers.
Nowadays the market uses as well Studless Chains Quality 818-4-8 ( Grade 80 ) for Towing Bridle Arrangements. Advantage: it's less heavy then anchor-chain with studs easier to handle + an higher MBL. Check our downloads for your demands , remember the Tonnage Mentioned is the Safe Working Load. If you want to know the MBL multiply the SWL by safety factor 4 ( this for Chain DIN EN 818-4 )
For Tugboats / Shoalbusters your Bollard Pull multiplied by factor 3 in The Netherlands with this outcome you are able to check the correct diameter of chain needed with the right MBL .
Sample: Tugboat has 40 Tons of Bollard Pull, Safe Pulling Factor in The Netherlands for towing is 3. The outcome is 120 Ton and this should be equal with the MBL of the requested chain diameter. In this case we would get a Chain Diameter of 32mm as it has 32 Ton SWL, if you multiply this with 4 you will get 128 Ton MBL this will match the bollard pull of your tug including the Safety Factor 3.
The chain we are supplying for towing bridles are nowadays special black lacquered, see picture one !
Grade 80 lifting chain is made from alloyed steel and is specifically designed for overhead lifting applications. This grade of lifting chain has a good strength-to-weight ratio and excellent durability. Grade 100 lifting chain is also made of alloyed steel, but is hardened and tempered for superior durability and fatigue resistance. Most Grade 100 lifting chain is made of Herc-Alloy 800, a heat-treated alloy with very high strength. Although many types of chain fittings are available, Grade 80 fittings should not be used with Grade 100 chain.
Selecting lifting chain requires an analysis of performance specifications. Lifting chain size is measured in inches (in.) or millimeters (mm). Common sizes include 7/32 in. (5.5 mm), 9/32 in. (7.0 mm), 5/16 (8.0 mm), 3/8 (10.0 mm), 1/2 in. (13.0 mm), 5/8 in. (16.00 mm), 3/4 in. (20.0 mm), 7/8 in. (26 mm), and 1 1/4 in. (32.0 mm). Nominal dimensions include inside length and inside width. Other important considerations for choosing lifting chain are the approximate number of links per foot (ft.) and the approximate weight (lbs.) per 100 ft.