http://www.mermaid-consultants.com/ship-towline-arrangement-verification.html
Online calculator to verify capacities of following towing equipments for specified bollard pull.
1 Smith Bracket (Tow attachment point )
2 Chafing chain or Bridle wire
3 Shackles (Bridle chain to Bridle wire)
4 Bridle wires (with hard eye)
5 Shackles (bridle wire to founder plate)
6 Founder plate
7 Shakles (Founder plate to lead chain or pendant wire)
8 Lead chain or pendant wire
9 Norwegian buoy