Jim Kropfeld maneuvered Miss Danash to an impressive victory in the second heat of Grand Prix International hydroplane competition in the President's Cup Regatta yesterday on the Potomac River near Hains Point.

Miss Danash entered the second of three laps even with Golden Nugget, driven by Kropfeld's brother Tom, accelerated sharply from the inside position to pull away. The winner covered the course at an average speed of 91.37 mph before nearly 5,000 spectators.

Long Gone, driven by Kent MacPhail, started well and breezed to victory in the first heat of the Regatta's main attraction, in which four of the 12 entries succumbed to engine trouble.

First-place finishers in each heat are awarded 400 points, second place earns 300 points and third place 225. All finishers receive points.

After two heats today, the six boats with the most accumulated points will vie for the President's Cup at 5 p.m.

Winners for the regatta's seven other boat classes are determined by total points for the two days. Trophies also were awarded to yesterday's top finishers.

MacPhail was not overconfident after averaging 89.552 mph during his victory. "I'd say there's about eight other boats with as good a chance to win it as me. It's good to be out front but with 2 1/2 laps left, every vibration, strange sound and peculiar smell works on you and makes you wonder."

In the 145-cubic inch class, Stuart Shane prodded Hijacker into early leads to win two heats over Doug's Wanton Duchess. Shane takes 800 points and yesterday's title into today's quest for the overall championship.

Yellow Side Up and Creme-de-Menthe traded narrow wins in the super stocks class and both totaled 700 points. The day's championship went to Creme-de-Menthe, based on its slightly lower total elapsed time.

In the 280-cubic inch class, Nudder Bo, driven by Wheeler Baker, negotiated the 1 2/3-mile course at an average of 76.401 and 74.565 mph, easily outdistancing all competitors.

The widest margin of victory occured in the 2.5-liter class, where Chris Oliver averaged 65.406 in Every Penny while second place Camesto Play averaged only 44.887 mph.

Competition was fierce in the Jersey skiff class. Indian Summer garnered 700 points with first- and second-place finishes while Veri Cheri stayed within striking distance with 555 points.