THIS CHAPTER DISCUSSES the brittle fracture of the Ingram Barge which occurred in 1972. This ship had a notch toughness level of about 55 ft-lb at the service temperature, well above what would generally be considered adequate to prevent a brittle fracture. However, in this case, the three-dimensional constraint based on the design was such that the principle stresses, σ1, σ2, and σ3, were relatively high in tension. This triaxial state of tensile stresses prevented the development of significant shear stresses at the fracture origin. Thus, as would be concluded from strength of materials principles, brittle fracture could occur when the three principal stress components are large.