Maintenance-free radars are strongly demanded by customers, because radars are more and more frequently relied upon for ensuring safe navigation of vessels-consequently making the maintenance costs burden to replace magnetrons with limited life. On the other hand, radar frequency band is demanded to be narrowed because of the present congestion of radio frequency resources. In response to those demands, JRC has developed X-band solid-state radars for Safety Of Life At Sea (SOLAS) vessels. Due to the stable oscillation by the solid-state device and the waveform optimization technique applied, the developed radar has successfully reduced the necessary bandwidth down to 70%. Furthermore, we have confirmed through the field evaluations on a practical vessel that the developed solid-state radar achieves the matching sensitivity despite its 300 W of transmission, and the superior clutter suppression performance in comparison with the existing magnetron radars, as the benefit from the pulse compression and the coherent processing.