DL 3913 then DL 474 at Seattle
Portland (Oregon) → Seattle → Boston
Timetable, Seattle time
20:50DL 3913 from Portland (Oregon) at the gate
13:40DL 474 to Boston leaves the gate
16 h 50 apart on the timetable, overnight
DL 474 leaves 16 h 50 after DL 3913 arrives on the timetable: more than half a day, so not a connection we count.