Chinese have a bonus that their docks “work 20% faster”, but it seems to be indiscriminately adding 1-3 seconds to everything, except Fishing Boats and Transport Ships.
Trade Ship/Baochuan/Navigator Lookout/Swivel Ballista/Extra Hammocks/Explosives
Base Time: 60 Seconds. 60*0.20 = 12. 60-12=48
Chinese Time: 49 Seconds
Junk/Explosive Junk
Base Time: 35 Seconds. 35*0.20=7. 35-7=28
Chinese Time: 29 Seconds
War Junk/Additional Sails
Base Time: 45 Seconds. 45*0.20=9. 45-9=36
Chinese Time: 37 Seconds
Extended Lines
Base Time: 75 Seconds. 75*0.20=15. 75-15=60
Chinese Time: 62 Seconds
Chaser Cannons:
Base Time: 90 Seconds. 90*0.20=18. 90-18=72
Chinese Time: 75 Seconds