At the start of the Star Trek episode "The Tholian Web" the crew of the Enterprise can somehow "see" the wreck of the Defiant although it doesn't register on the ship's sensors. Then they beam over to check things out.
If it doesn't register on the sensors then where did they get the coordinates for the transporter?
If they can see it visually, that's enough to know its distance and orientation. With that, because it's a sister ship, they exactly know the size and interior layout, so that's enough to go on. Of course they might not know the exact location of crew members, so might take a risk of beaming into one, but maybe the writers didn't think of that.
