Sonar self noise data describe the acoustic quality of a sonar carrier and are needed to get reliable statements about the performance of the own sonar systems. In the first part a short overview about the significance of self noise, possible sources, transmission paths and measurement techniques is given. The main issue of the presentation relates to the difference between stave and beam responses of noise. The real correlation and phase velocity of self noise result in a greater value for the array gain than it is valid for isotropic noise. This behavior is demonstrated by evaluation of measured towed array and flank array data. The spatial correlation which is determined for a towed array depends strongly on the dominating noise, at low speeds: ambient noise, at high speeds: self noise. For the evaluation of the flank array data a wave-number analysis is applied. In case of a linear array with equidistant stave positions, a 2-dimensional Fourier transformation is appropriate to perform the analysis. The results state, that self noise responses lay partly outside the target related sector. For the flank array and the medium frequency arrays installed on a modern submarine some self noise levels depending on speed are presented. The data demonstrate that at typical operational speeds self noise influences can be neglected mostly.