Abstract: This paper calculates the structural reaction and bending moment of the three saddles under locally concentrated load and uniformly distributed load through analysis on the force characteristics of the three-saddle vessel. And the conclusions are as follows: when the three saddles are arranged, the locally concentrated load is set in the middle of two adjacent saddles and the middle fixed saddle is arranged in the middle of the vessel, then the force on the vessel is uniform and the force on the three saddles are reasonable; the vessel has minimal local stress when it’s checked.

Key words: three saddles, stress, bending moment, horizontal vessel