barge, flatboat, hoy, lighter

a flatbottom boat for carrying heavy loads (especially on canals)

• dredger — a barge or barge-like vessel used for dredging
• houseboat — a barge that is designed and equipped for use as a dwelling
• pontoon — a floating structure (as a flat-bottomed boat) that serves as a dock or to support a bridge
• scow — a barge carrying bulk materials in an open hold
• wherry, Norfolk wherry — (British) sailing barge used especially in East Anglia

• boat — a small vessel for travel on water