Is it true that Shanghai recruits seafarers to do general work?

Not reliable. There are a lot of false information on the internet about the so-called high-paid recruitment of seafarers and merchandisers. They are basically liars. Liars who cheat money by handling passports, seamen's certificates, visas, border defense certificates, medical examination fees, training fees, referral fees, security deposits, etc. Be careful of being cheated.