Section - Swimming
Swimming in is an action applying to one visible thing. Understand "swim in [something]" or "wade in [something]" as swimming in.
Carry out swimming in: say "You don't see a good place to swim here."
Vague swimming is an action applying to nothing. Understand "swim" or "go swimming" as vague swimming.
Carry out vague swimming: say "You don't see a good place to swim here."