There are 3 types of chains in the fender system: tension chain, weight chain, and shear chain.
- The main function of the tension chain is to protect the fender from damage while under local compression
- The main function of the weight chain is to support the weight of frontal panel and face pad.
- The main function of the shear chain is to protect the fender from damage while in shear deflection.
The following items should be noted for the design of the chain:
- The chain dimension should be as exact as possible, not too loose or too tight.
- The chain can not be twisted as this reduces the load capacity.
- Open link is preferred.
- The initial (static) angle of the chain is important. Normally weight chains are set at a static angle of 15-25° to vertical and shear chains are set at 20-30° to the horizontal. Any failure will cause the chain ineffective.
- All the chains must be with safety factors which should be 2-3 times of the workload.
- Shackle Selection. The dimension of the shackle is usually the same as the dimension of the chain. but if the shackle is required to bear the same load as the chain, then a thicker shackle is preferred.