Complex sentence: Puget Sound believed that they could complete work on "Maryland" in 123 calendar days (about four months)--if the work would be given a priority equal to that of s refit and higher than new construction.
Split into simpler sentences: Puget Sound believed that they could complete work on "Maryland" in 123 calender days--about four months. This was assuming that the work would be given a priority equal to that of s refit and higher than new construction.