The present work presents a series of experimental distortion analysis of square shipbuilding steel plates with an attached stiffener. Two approved fillet welding configurations are applied to attach the stiffener using shielded metal arc welding at Port Said Shipyard. The specimens are welded using continuous and intermittent chain fillet welding for variant plating thicknesses with constant stiffener geometrical configurations, where two welding passes are applied. The effect of different fillet welding geometry on the induced initial imperfection amplitudes for different base plating thicknesses is investigated. The imperfection shapes are tracked, and the amplitudes are measured during and after the welding process. The imperfection amplitudes for each plating thickness and welding geometry are analyzed considering both preheat after the first pass and heat relief. Several relationships considering the welding time and the amount consumed electrodes are performed for different plating thicknesses and welding geometries. A comparison between existing empirical formulations and the observed results is performed in the form of plate slenderness, showing reasonable conclusions.