lockrd posts (A)

[CyberSlappingBunny]

how do you lock certain posts that you only want viewable by crew members and captains in a guild?  

[Ebania]

You can lock a thread by clicking the button on the bottom left of any thread in a guild (of which you are a crewmember, vice captain, and captain) which will make your thread read-only. This means that only crewmembers will be able to post in that thread or edit any posts in that thread, but any member will be able to read the contents of the thread.

You can't create a thread and make that thread only viewable by crew. You can, however, create a subforum only viewable by guild crew and post the thread in there.