B-24s equipped as "Snooper" or SB-24s did not need to visually site the target.
Here is a description on 868th Squadron history.
"The squadron was equipped with RADAR equipped Liberators (unofficially designated as the SB-24 "Snooper") with an extra crew member to operate the SCR-717 10 cm RADAR; the SCR-729 Aircraft RADAR beacon and a number of other specialized devices. The mission of the squadron was for low level, anti-shipping strikes under the cover of darkness. They had this capability because the radar-sighting devices permitted operation of the bomb-release mechanism irrespective of visual sighting of the target."
A book by Stephen M Perone on the topic.
http://www.amazon.com/World-War-B-24.../dp/188754402X