The Doombolt Chase Series 1 1978 Written by Don Houghton, directed by Robert Fuest and Peter Graham Scott. A 6 episode series from ITV that's only vaguely science fiction. It's mostly a teen adventure story involving the British Navy.
Commander David Wheeler re-directed his Navy ship to run down a small boat. It didn't appear to be occupied but they don't stop to check. Wheeler gives no explanation to the Navy and is court-martialed. Wheeler's son Richard doesn't get any explanation from him. Richard decides to investigate with the help from friends Pete and Lucy. Pete is a junior seaman and was on the bridge when the incident happened.
They stumble on some baddies who are lead by a scientist. He worked on the Navy's beam weapon project but quit about a year ago. He's improved the beam weapon and plans to blow up a giant supertanker if they don't give him £5 million. The teens help thwart the plan. At the end it's revealed that Commander Wheeler was court-martialed as part of a plan to smoke out the baddies.
It's mostly entertaining, there's a lot of running through fields. Helps pad out the 6 eps, I guess. I probably wouldn't watch it again.