I am a sailor with a mainland passport. Do I need a Hong Kong and Macao Pass to go to Hong Kong?

Of course you need it. Mainland passport holders who are destined for Hong Kong should use the Hong Kong and Macao Pass and Hong Kong endorsement, unless they travel to and from foreign countries (transit) through Hong Kong, they can transit directly without a Hong Kong and Macao Pass.

If you go to Hong Kong by boat, you may be able to enter the country with a seaman's card, but if you go directly with a seaman's card, I'm afraid not.