THE YEAR WAS
The Haunted Shipwreck
Written by Ray Bailey(artist), Don Segall(writer)
#4 - 14 pages - Skooby and his dolphin friend come upon an intact sunken wreck but one with its indoor lights aglow. It is really just a doorway to a tunnel to the underground lair of General Zomba who has an army of "mindless one".
Here are the pages I have of it.