The computation of the deformation of this dam under the pressure from the water of one of the largest storage lakes in Switzerland was one of the first outside orders which IAM received after its foundation in 1948. Mathematically it involved the solution of a boundary value problem with a two dimensional elliptic partial differential equation which could only be computed by using relaxation methods. At the start when the programmable computer Z4 was not yet available and only electromechanical  calculators existed at the institute, Southwells' point relaxation method was used. Stiefel engaged for this a former German naval officer, Dr. F. Krantz, but he worked on the tedious computations also personally. Often he followed the recommendation of a famous instructor in the Swiss army  "If the 24 hours of the day are not sufficient for achieving your work then use also the night" and computed during a whole night. Several times I  joined him in these strenuous nightly exercises. I think that this rather dull and tiring effort also motivated him to find a better method for solving the system of linear equations. In support of this I found recently that David M. Young, one of the developers of the successive overrelaxation method, stated in his article “A historical review of relaxation methods” (published in “A history of scientific computing”): „ my propensity for making numerical errors was so strong that I knew that I would never be able to solve significant problems except by machines “ and this determined him to continue his PhD thesis on relaxation methods suitable for the use with computers.