Engine Chocking and Holding-Down Arrangements
How a main engine is secured to its seating: epoxy and cast iron chocks, long holding-down bolts, distance tubes, side chocks, end chocks and the afloat chocking sequence.
Engine chocking and holding-down arrangements are how a main engine bedplate is secured to the ship’s seating: on cast iron or poured epoxy chocks, through long elastic holding-down bolts with cast iron distance tubes, with athwartship restraint by side chocks and fore-and-aft restraint by end chocks. The three devices restrain three different directions and are designed separately.
The full article will cover chock material selection and the compressive modulus that decides it, resin pour depth, cure schedule and shrinkage, taper conventions on liner-fitted chocks, bolt pre-tension and hydraulic tightening, the seating structure in the double bottom, the sequencing that defers final chocking until the vessel is afloat, and the survey and re-chocking case after a bedplate or alignment repair.
The chock properties and the side-chock and end-chock arrangement as they apply to a large two-stroke are covered today in A-frame and column design .