Complex sentence: Sea trials were planned beginning in March 2017 with delivery expected in May 2017, but in January 2017 it was reported that there were "technical issues" delaying her sea trials to mid 2017.
Split into simpler sentences: Sea trials were planned beginning in March 2017 and delivery expected in May 2017. It was reported in January 2017 that there were "technical issues" delaying her sea trials to mid 2017.