According to witnesses who were on the Annabelle Lee river boat, a small leisure boat came up from behind the river boat, hit a dock, and then hit the river boat.
Brooke Kantack was on the river boat and said the crash took place on the river near Metro Park.
"Two people fell out and three people were left on, but one got out and tried to swim to the fellow victims," Kantack recalled.
Kantack said at least one woman from the smaller boat was plucked from the water and pulled onto the river boat. Kantack said she heard the woman say her leg was in pain.
Kantack said she believed the smaller craft was speeding because it passed the river boat so quickly.
Police were on the scene investigating.
Witnesses said no one on the river boat was hurt.