Accurate weighing on board of a seagoing fishing vessel is no sinecure. First and foremost, the ship is continuously rolling and stamping because of the waves. Furthermore, the motors, hoisting tools, winches and the like cause a plurality of vibrations with the corresponding harmonics. Using existing instrumentation, PENKO Engineering developed a weighing system with built-in compensation for all mentioned disturbing effects. This arithmetic compensation is possible due to the unmatched high measurement speed and internal resolution these instruments possess. The availability of a reliable weighing data is the basis for dosing the captured fish in batches. In practice, thanks to this method, it appears possible to assemble the batches of fish with a, for these conditions of use high, accuracy ≤ 1%. Because the batches are carefully dosed, the fisherman reduces give away due to overweight and does not need to freeze it either. That means two times profit, in money and for the environment. Finally, with the PENKO program TP Datareporter the weighing data is immediately available, recorded and processed. This turns measurement results into knowledge.