The Cambridge crew used "cleaver" blades, which weren't invented for three years after the film was set.
The depiction of the race includes real footage of the Boat Race in 1997 - the problem being that the crews are the wrong way round. This can be seen during one of the cuts between actor crew and actual Boat Race footage.
Consecutive (in the final cut) shots of the race are inter-cut from takes made at very different states of the tide. The water level in the river goes up and down like a yo-yo between them.
The opening sequence depicts the end of the 1986 boat race and shows the event as being sponsored by Beefeater Gin as the crews cross the finish line. The film makers must have used actual footage from a different year, as Beefeater didn't actually take over sponsorship of the Boat Race from Ladbrokes until 1987, the year when the final race is supposed to take place.