Introduction on Delayed Mode QC: Recalibration is generally not possible due to the no recoverable nature of floats, so float datasets are usually check to an indirect way. Here we present the application of a method based on mapping a set of calibrated data by objective analyzing to the float profile position. The method applied at the Coriolis Data Center is the method of Annie Wong et al (2003) [1] adapted to North Atlantic environment by Lars Böhme [2] to produce the delayed mode data for Gyroscope project in a first time. Recalibration is set up to correct sensor drifts by using historical hydrographic data. The used objective mapping method takes into account the high spatial and temporal variabilities of the North Atlantic [2]. Assuming that a conductivity offset changes slowly over time, the float measurements are fitted linearly to the mapped salinities in potential conductivity space by weighted least-squares. The result is a set of calibrated salinity data with corresponding uncertainties. [NOT CONTROLLED OCR]