The Foster lock-gate of the dry dock in Barcelona Harbor was replaced because it was reaching the end of its usefull life period. The dealer MARINA BARCELONA 92 put us in charge of the operation to switch it for a new one. This operation was difficult due to the dimensions of the gate and its weight. Besidese displacing the new gate, driving it by a floating system and placing in in the right position, it was necessary to perform an intermediate operation, rotate the pavement to be able to assemble the temporary floats, finish welding it and paint the unreachable face of the gate. To do so, the old hinges were used. These ones were also replaced by anchoring them in concret blocks.