Coach Ed Cavanaugh knew what his Army football team had to do today to defeat Navy and give him some chance to keep his job.

"We have to play a very solid, not-beat-yourself game, pretty close to perfect," Cavanaugh said, before the Cadets almost certainly assured him a place in the unemployment line by beating themselves--with a big assist from a stingy Navy defense.

A fumbled punt and a pass interception gave Navy a 10-point lead in less than five minutes, more points than Army managed all game as the Midshipmen ground out a 24-7 victory before 67,307 at Veterans Stadium.

"It wasn't pretty, but we won," Navy's Gary Tranquill said after his first game against Army as a head coach. He also was a winner all four times he assisted George Welsh, departing the Naval Academy the year before the only West Point success of the last decade, in 1977.

Apparently touched by Army's early gifts, Navy fumbled at its 15 to set up the Cadets' touchdown. At that, Army needed six plays to reach the end zone. Then the teams took turns displaying offensive ineptitude until a 25-yard punt return by Napoleon McCallum got the Midshipmen moving in the third quarter.

Navy's offensive line began to push the Cadets back and sophomore quarterback Ricky Williamson, who had played tentatively the first half, threw for a touchdown on his team's only pass of the second half. That gave the Midshipmen breathing room. Another McCallum punt return, of 15 yards, had a personal foul added on to it and the Midshipmen then drove 27 yards in eight running plays to complete the scoring.

Army was limited to 58 yards rushing, its fewest against Navy since 1952. Among Navy's defensive heroes were rover back Brian Cianella of Langley High School in McLean, Va., with 10 tackles, an interception and two passes broken up; defensive end Rick Pagel, eight tackles, three for losses, and a key fumble recovery, and linebacker Andy Ponseigo, whose 15 tackles brought his Navy one-season record to 168.

"Luckily, we held them on defense until the offense could get it going," Cianella said. "They scored seven points, but they got the ball on our 15 and had to fight for that. There was no way we were going to let them score today."

The first touchdown in this rivalry since 1980 came early, after Army's Dee Bryant fumbled a punt at the Cadets' 24 and Pagel recovered at the eight. Three running plays produced the score, with McCallum driving the last two yards through right tackle.

On the third play following the kickoff, Cianella cut in front of fullback Art Zarone to intercept Rich Laughlin's pass into the flat. Cianella caught the ball at the 29, got back to the 14 and griped later, "After I picked it off, I figured what an idiot I was for not scoring."

Tranquill felt even worse. A personal foul against the Cadets gave Navy a first down with three yards to go at the Army seven. Instead of following the previous successful touchdown plan, Tranquill ordered three straight passes, all poorly thrown by Williamson, and Navy had to settle for Todd Solomon's 24-yard field goal.

"That was dumb, wasn't it?" Tranquill said.

Rich Clouse, playing his first game as a fullback, fumbled at his 15 and Army tackle Mike Staver recovered to set up his team's touchdown, scored by Laughlin on a three-yard keeper as his faked pitch to fullback Warren Waldorff made two defenders pirouette out of his path.

Solomon missed on a 49-yard field-goal attempt in the second quarter, then was good from 42 yards. That made it 13-7, right? Wrong. Army's Tom Morgan was offside, giving the Midshipmen a first down at the 20. When three plays gained nothing, Solomon missed from 37 and old salts had to wonder whether the lost three points might prove decisive.

"An old coach told me when you have points on the board, not to give them up," Tranquill said. "But the score was 10-7 and I felt 13 wasn't good enough."

Actually, 10 were enough. The Cadets did not mount another serious threat, although Laughlin's 38-yard pass to a wide-open Waldorff against a Navy blitz brought them close enough for Craig Stopa to come up short on a 49-yard kick at a tying field goal.

McCallum, ranked 10th nationally in punt returns, slipped three tackles on his 25-yard run to the Army 40 midway through the third period. Seven running plays produced a second and nine at Army's 17, then Williamson redeemed himself for a two-for-13 first half.

Calling an audible when he saw Army's great safety, Mike Williams, cheating too close to the line of scrimmage, Williamson threw to split end Bill Cebak in the end zone.

"The play was supposed to have been a short pass to Napoleon, but the free safety came up and locked on the tight end, so I figured I could throw behind him," Williamson said. "They backed up, but Bill got free. That was my first touchdown pass, and coming against Army makes it really big."

The next time Army punted, McCallum caught the ball at his 43 and got upfield to the Army 42, from where the personal foul was tacked on. Once again, the scoring drive required eight plays, with fullback Jim Scannell plunging across from the one.

With the game virtually out of reach, Cavanaugh called on quarterback Billy Turner, the freshman out of Virginia's Fort Hunt High. Turner completed his first two passes, carrying the Cadets from their 35 to a third and inches at Navy's 43. With Pagel leading the defensive charge, Army was unable, in two tries, to get those inches.

Turner completed eight of 16 passes for 79 yards and gave promise of better offensive ability for the Cadets next year. Cavanaugh, almost certainly, will not be around to enjoy it.

"Nothing has been said about next year," Cavanaugh said. "I like to eat, but it's understandable if I'm not back. It's a matter of wins and losses."

While Navy finished at 6-5 for its fifth straight winning season, Army closed at 4-7 for its fifth straight losing season.

"There is no question our program has progressed under Ed Cavanaugh," said Carl Ullrich, Army athletic director. "The question is whether it has progressed as much as it should have. We felt that the last two years we had the personnel for a winning season."