Question: When were the first magnetic compasses used by chinese ships?
Answer: 1040 -- 44
Disambiguated annotations:
qaPairs: question: When were the first magnetic compasses used by Chinese ships for maritime navigation?
answer: 1111-1117
question: When were the first magnetic compasses used by Chinese ships for navigational orienteering?
answer: 1040-1044
1040 -- 44