The United States will have more naval power concentrated off Iran today than at any time since the hostage crisis began.

Navy officials, in confirming there would be 37 ships and 34,000 men in the Indian Ocean region as of today, said last night that there were no signs that President Carter intended to use this power.

However, if the president should surprise these officials, he could order into action about 400 aircraft aboard four carriers and 1,800 Marines on amphibious assault ships off Iran.

The official explanation is that the aircraft carriers Constellation and Eisenhower are going to relieve the carriers Coral Sea and Nimitz. The Coral Sea, Navy officials said, has been in the Indian Ocean since Feb. 10 and the Nimitz since Jan. 14.

The nuclear powered Nimitz launched the eight helicopters which were to rescue the hostages from the U.S. Embassy in Tehran. Before launch, an administration official said yesterday, the Nimitz raced away from a Soviet electronic eavesdropping ship, leaving it 80 miles in her wake so the Soviets could not detect the start of the ill-fated rescue mission.

The Coral Sea and Nimitz have been on station so long that their relief would be standard procedure. The president, in an effort to make a show of force off Iran, conceivably could keep all four carriers in the Indian Ocean, however.

Although option papers written by the Joint Chiefs of Staff over the last several months include bombing Iran from carriers, this action has been rejected to date, presumably because it would not guarantee the release of the hostages. t

Since the Iranian takeover of the U.S. Embassy in Tehran last November, the United States has increased its naval presence in the Indian Ocean and improved the military facilities on the island of Diego Garcia.

The number of ships in the Indian Ocean region during this crisis period has averaged between 20 and 25, the Navy said, with crews averaging 20,000 people.

Besides showing the flag with this naval presence in the Indian Ocean, the Carter administration has been sending B52 bombers from Guam over the area, apparently to dramatize U.S. long-distance bombing capability.

B52 bombers could land and take off from Diego Garcia, a senior defense official said, by lightening the usual load of bombs and other weaponry. With a maximum load of bombs, the wings of a B52 droop so low that wheels under the wingtips roll along the runway on take off. The runways at Diego Garcia are too narrow to accommodate wingtip wheels.