Submerged-arc welding is studied with special attention to hot cracking and to change in gap width in butt-welding of tack-welded plates. The most important welding parameters are the welding speed, the arc energy per unit length of the weld and the number of tack-welds for a given length of the weld. Eight cases are analyzed using the finite element method. The change in gap width and the risk for hot cracking are studied for two different values of each of these welding parameters. It is concluded that it is possible to find a practical combination of welding parameters that minimizes the change in gap width. The welding speed in that combination should be fairly high. The location of the maximum value of calculated change in mechanical strain across the weld, , agrees well with available experimental observations of the location of that crack front which is closest to the edge in the end portion of butt-welded plates. The transverse stresses become compressive at the edge and tensile at a short distance (about 0.1 m) from the edge shortly (about 30 s) after removal of the heat source. Therefore it is believed that the hot cracks nucleate at temperatures around 1200°C due to high transverse strains and then propagate towards the interior of the plate due to the transverse tensile and compressive stresses. It is then concluded that the highest risk for hot cracking is to be found at the end portion of the butt-welded plate for low welding speeds and large values of the arc energy per unit length of the weld.