Eleven Coast Guardsmen were missing and presumed dead last night after their training vessel, the 41-year-old cutter Cuyahoga was rammed Friday night by an Argentine freighter and sank in one of the Chesapeake Bay's major shipping lanes.

Coast Guard spokesmen called the accident "one of the worst" in the service's recent history.

Details of how the Cuyahoga, on a weekend, training exercise in the Bay, collided with the 561-foot Argentine freighter Santa Cruz II remained unclear last night.

But the only survivor permitted by the Coast Guard to talk with reporters yesterday told of seeing the southbound Argentine ship off the cutter's starboard (right) side moments before its bow struck the smaller Coast Guard vessel.

"When I got up on deck I saw the vessel Santa Cruz off the starboard beam . . . ," said Petty Officer 1st class Roger Wild, 32, one of 18 Coast Guardsmen who was pulled from the Bay by rescuers Friday night. "It looked like he was going to come pretty close to hitting us on the stern.

"From where I was it looked like we were going to have a starboard-to-starboard passage," said Wild, who was second in command on the Cuyahoga. He said the two ships had exchanged whistle blasts moments earlier - signals of each ship's maneuvering intentions.

But suddenly four sharp blasts of the Santa Cruz's whistle cut through the night - a signal that the freighter feared it was in danger, Wild said. "Five to 10 seconds after the danger signal, he hit us on the starboard side," Wild said.

The Coast Guard cutter immediately heeled over to a 50-degree list. "We started pulling people out of the (ship's) bridge and trying to put them over the side of the vessel and into the water," Wild said.

Many of the cutter's 13 crewmembers and 16 officer cadats on their first training cruise from a Yorktown, Va., base, were trapped below deck, he said. The cutter, the oldest of its class still in service, stayed afloat "three or four minutes and then she went out of sight," Wild said.

In those minutes the crew managed to free a small service boat and place some injured crewmen in it. Others clung to the side of the small boat.

Initial rescue efforts were hampered by strong currents in the area, about four miles off Smith Point on the Virginia side of the Bay near the mouth of the Potomac River and the busy Baltimore shipping channel. The site of the collision is near the Maryland-Virginia border and currents in the Bay there were described as strong by one Coast Guardsman.

The rescue efforts were also slowed by what a guardsman called "massive confusion" over the precise location of the 9:10 p.m. accident. The survivors were taken aboard the Santa Cruz which had left Baltimore four hours earlier with a load of coal for Buenos Aires.

None of the 28 crewmembers aboard the year-old Santa Cruz II, owned by an Argentine shipping company, was injured. The ship's bow was punctured, leaving a 10-by-6-foot hole, but was otherwise undamaged, the Coast Guard said. The Santa Cruz was being piloted by a Chesapeake Bay pilot from the Association of Maryland Pilots at the time.

Pilot John Hamill of Baltimore, a seven-year veteran of Bay sailing, was described by his superior yesterday as "competent and experienced." George Quick, president of the Maryland pilots group, said he spoke with Hammill yesterday and said that Hammill "sounded concerned, but I wouldn't say upset."

Most of those aboard the Cuyahoga were officer candidate students between the ages of 23 and 30 and had completed six weeks of classroom training at the service's Yorktown Reserve Training Center.

"Their role on board ship was to observe; it was practical training," said Cpt. Charles Blaha, head of the Yorktown base. The students had received "some" emergency training before they had embarked Friday afternoon on what was to be a three-day exercise on the Bay.

Maryland, Coast Guard and Navy units searched the scene throughout Friday night and at dawn yesterday divers went into the bay. They located the Cuyahoga, lying on its port (left) side under 57 feet of water, spokesman said.

Divers, seeking signs that some of the crew might have been able to survive in airpockets in the sunken ship, rapped on its hull yesterday afternoon. "There were no signs of life," said Cmdr. Jack Goldthorpe, a Coast Guard spokesman.

Shortly after midnight Friday, four of the survivors were taken by Coast Guard helicopter to the Patuxent River Naval Air Station Hospital in Maryland. One survivor remained hospitalized yesterday with head injuries.

Late yesterday afternoon, the other survivors were flown to Newport News to be reunited with families.

Names of the missing Coast Guardsmen were being withheld pending notification of next of kin.

During the day yesterday, up to five helicopters from the Coast Guard, Maryland State Police and Marines for Quantico assisted in the search for survivors.

"What really hurts the Coast Guard," said Lt. John Kerchen, commander of a rescue boat after a night of searching, "is that each of us knows some of these men."

The area around the collision site was divided into 60-square mile search sections and Coast Guard cutters were assigned to each section.

Searchers at the collision site Friday night said the waters were littered with pieces of wood, oranges and hair brushes afloat on a slick of oil where the cutter had gone down.

After the collision the Santa Cruz dropped its anchor. Workers tried yesterday to complete make-shift repairs on the vessel which Coast Guard officials said would probably return to Baltimore and dock for the duration of an investigation.

The Coast Guard convened a board of inquiry yesterday, headed by a rear admiral, to investigate the collision.

The Coast Guard cutter was commanded by Chief Warrant Officer Donald K. Robinson of Yorktown, a 20-year Coast Guard veteran who survived the tragedy.

Coast Guard officials said the sinking of the Cugahoga was the worst Coast Guard disaster in 10 years. In 1968, the White Alder, a Coast Guard buoy tender, was struck by a ferry in the Mississippi River and sank with all 20 crewmembers lost.