The deafening noise emanating from the vicinity of Hains Point Friday will have nothing to do with 707s making approaches to nearby National Airport. It will be merely the world's biggest and fastest hydroplanes trying to qualify for the 46th President's Cup Regatta this weekend on the Potomac River.

An eight-boat field, incuding two former President's Cup winners - Atlas Van Lines and Miss Budweiser - will view for the first-prize slice of the $30,000 purse. The drivers will earn points in each of the four heats (two Saturday and two Sunday) leading up to the final race Sunday at approximately 5:10 p.m. The winner's share is determined by total number of points.

An expected crowd of 40,000 will witness the debut here of Bill Muncey's new cabover boat, which was designed by master engine-builder Jim Lucero.

It's the Atlas Van Lines, which became only the second thunderboat in three years to win its first race when it captured the Chapmion's Spark Plug Regatta last week in Miami. Muncey, a five-time winner of the President's Cup, drove his new machine to a course-record 108.893 miles per hour over a 1 2/3-mile course in Florida. It was the 39th career victory for the 48-year-old corporate president.

The Rolls-Royce powered boat has the cockpit positioned in the front rather than near the stern.

All the boats will have to complete two laps on the 2 1/2-mile course at an average speed of 95 m.p.h. today to qualify for the heats.

The races were hampered by rain the past two years. General chairman Tom Hurney said that, weather permitting, this should be one of the most successful regattas.

"It cost $80,000 to stage the regatta and we have to beg, borrow and steal every penny we can to cut costs," said Hurney. Everyone volunteers their time and this is a nonprofit public-service event."

The 73-year-old event, which has drawn crowds of more than 200,000, rank high among the more dangerous sports. Eleven years ago, three persons were killed here during a collision of boats. In the period from 1966 until 1969, seven drivers lost their lives in racing accidents.

The President's Cup is considered by owners and drivers to be one of the most prestigious on the 10-city tour and also the most dangerous because of the debris-laden waters of the Potomac.

The regatta also includes nine other races Saturday and 11 others Sunday. Races get underway at noon.

Admission fees at Hains Point will be $4 for adults and $1 for children under 12. On the Virginia side, the fees are $4 for car and driver, $3 for each passenger and $1 for children under 12.