The U.S. Navy has put a "secret" stamp on an unpublished article that questioned whether two American aircraft carriers "survived" simulated Soviet submarine and surface ship attacks in Ocean Venture '81, the largest exercise ever held by the Atlantic Fleet.

The writer of an article solicited by the nonofficial Naval Institute's Proceedings magazine, Lt. Cmdr. Dean L. Knuth, was the chief analyst of Ocean Venture '81, and its 1980 predecessor. In both naval exercises he was the American adviser to the British Navy's Vice Adm. John Cox, who was responsible for protecting the North Atlantic Treaty Organization "Blue" team's nuclear-powered USS Eisenhower and conventionally powered USS Forrestal from attack by the enemy "Orange" team in the Norwegian Sea.

While the U.S. Navy's official position is that both aircraft carriers did well enough in the exercises to warrant the purchase of two more nuclear-powered carriers, Knuth is critical of that interpretation.

"It is hard for me to accept the proposition that the Eisenhower and the Forrestal reached the Norwegian Sea from the North Atlantic without being attacked successfully, even though the Orange threat was very low," Knuth said in one of several interviews from his home in Morristown, N.J.

"What happened after that is of lesser importance, partly because most of the Orange submarines and surface ships went into port. The fact is, our aircraft carriers were attacked by torpedoes or missiles from submarines in our major exercises. And yet the Soviet submarine force is many times larger than the handful of Orange submarines in Operation Venture," he said. The Soviets have 260 attack and cruise-missile submarines.

In December, Knuth submitted a draft to Proceedings, which is published in Annapolis. Later that month, the institute asked Navy security officials to review the paper so that no classified material would appear in the final version, which was being considered for the May issue.

Last Thursday, the Senate Armed Services Committee staff made inquiries of the Navy about the draft. On Friday, the Navy phoned Fred H. Rainbow, managing editor of the Proceedings, to say that it had classified the paper "secret."

The survivability of the aircraft carriers is at the heart of a bitter dispute about whether to spend $6.8 billion on two more nuclear-powered carriers, the most expensive single item of weaponry in the fiscal 1983 Defense Authorization Act.

The Senate began to debate the bill yesterday. The key test will come later in the week on a substitute proposal from Sen. Gary Hart (D-Colo.), who wants to delay consideration of one of the large carriers and to buy two "multi-mission" light carriers, at an estimated cost of $3.3 billion, in place of the second.

Hart recently received a copy of Knuth's draft. On April 26, Hart sent it to Sen. William S. Cohen (R-Maine), chairman of the Senate Armed Services sea power and force projection subcommittee, which on March 16 was briefed about the maneuvers by Adm. Harry D. Train III, the commander-in-chief of the Atlantic Fleet. The Navy has not yet provided a sanitized transcript of the testimony.

"While the specific conclusions presented in the briefing are classified," Hart wrote in an accompanying letter, "they are, as you know, strongly favorable toward the large aircraft carrier, in terms of its survivability and ability to operate even in high-threat areas. The conclusions were used explicitly to support and justify the current Navy program, which includes the two large carriers. . . . "

But, Hart continued, he had recently received Knuth's paper. "Far from proving highly survivable," the carriers were "effectively attacked by both submarines and surface ships," Hart wrote. The paper "raises serious questions concerning the accuracy of the information presented to the subcommittee by the Navy," he wrote.

In his letter to Cohen, Hart asked for an investigation of the results of Ocean Venture and of the Navy briefing and for a "hold" on authorizing the two large carriers "until the fate of the carriers in Ocean Venture '81 can be determined accurately." Cohen's staff began to make "preliminary inquiries" Thursday.

Yesterday, Cohen sent a letter to Hart in which he disagreed with Hart's interpretation of the briefing. After a review of all the pertinent materials, Cohen said in a statement: "The subcommittee was not misled and the conclusions of the exercise Ocean Venture as presented remain valid." He also said there is no reason not to buy the two large carriers, which are of the Nimitz class.

In reporting the defense authorization bill last month, the Senate Armed Services subcommittee said: "The Nimitz-class carrier remains the most cost-effective and survivable means of deploying aircraft to sea."

Hart disagrees. "We need to disperse our naval aviation onto a significantly larger number of ships--and two is not a significant number," he wrote other senators in a March 19 letter. "Yet, if we keep building Nimitz-class carriers, we simply cannot afford more than a 15-carrier force. We have priced ourselves out of the market."

Knuth, who is now in the Naval Reserve, was also in charge of the Atlantic Fleet unit that "reconstructed" the exercises from computer and other data. Navy Capt. Meredith A. Smith, director of operations for the Atlantic Command before his retirement in 1977, said in an interview from Norfolk: "I did in fact see the reconstructed report on Ocean Venture, as a Navy consultant. I have very much faith in Dean Knuth. He's very bright, and a super-analyst."

Smith described himself as "a great believer in the large aircraft carrier, and I wish we could have 18, 20, or more of them. But a carrier deck is the most expensive horizontal real estate in the world, and the cost of the carrier is just the tip of the iceberg, when you take into account the protection it requires. The cost boggles the mind. Can we afford it? I don't know."