J. J. Isler, Rolex Yachtswoman of the Year, and U.S. Olympic team member Cory Sertl and their respective three-women crews from California and New York tied for the lead after the first day in the Santa Maria Cup championship regatta match race yesterday just outside the Inner Harbor.

The second day of round-robin match racing will continue today from 10 a.m. to 4 p.m., with semifinals tomorrow at 10 a.m. and finals at noon.

The first-time event, headquartered in the HarborView Yacht Club and Marina and sponsored by Crown Central Petroleum Corporation, has attracted some of the top female sailors. They include three-time Rolex Yachtswoman Betsy Alison and her champion Adams Cup crew; Dawn Riley, past co-helmsman of the all-women Whitebread Round the World team and current America's Cup team member; past Italian Olympic team members Paola Ferrario and Paola Porta; and Hannah Swett, with three members of Brown University's No. 1-ranked team.

Each day's course is wind dependant and will be determined each day at 9 a.m. Course Alpha will be between HarborView and Harrison's, and Course Beta between Canton Park and Fort McHenry. Both are visible from shore. For course information call 440-9395.

Spectators are invited to meet the competitors at HarborView Marina and Yacht Club -- off Key Highway past the Maryland Science Center and Federal Hill park -- at the end of racing today at approximately 4 p.m., and at the final awards ceremony tomorrow at 3 p.m.