what is thrust blocking used for
Thrust block. A thrust block, also known as a thrust box, is a specialised form of thrust bearing used in ships, to resist the thrust of the propeller shaft and transmit it to the hull. Early thrust boxes. Multi-collar thrust box, with shaft.
Thrust blocks have fallen out of favor because thrust block design is based on unknown characteristics of soils. Thrust blocks were generally used on unrestrained connections (bell and spigot) for underground work. Most piping is now restrained in some manner using restraints such as megalugs.