The Head of the Charles is a three mile race, starting opposite the Boston University boathouse and ending across from Herter Park in Cambridge.

The first race will kick off at 8:15 a.m. tomorrow.

There will be 16 races, organized by age, weight, sex and rowing ability. The featured races are the men's and women's Championship Eights, scheduled to begin around 4:15 in the afternoon. Over 250 boats are scheduled to compete.

Boats are seeded in each event according to previous performances. Favorites in each event can be identified by their starting positions--indicated by the plastic cards affixed to the bow.

Spectators can spot the faster boats as numbers appear out of sequence during the course of the race. For instance, if boat number 10 has passed boat number 5, boat number 10 is racing well.

The Head of the Charles has a difficult race course. Rowers and coxswains must negotiate three sharp turns and pass under six bridges.

Collisions are rare, but hang out by the Weeks Bridge anyway and see how boats negotiate the treacherous turns.

The course record is held by the 1982 U.S. Naval Academy Championship Eight, which finished the three miles in 14 minutes and 24.6 seconds.

The event is sponsored by BayBank this year. Over 250,000 people are expected to attend.