"小舟摆渡船" can be translated into English as "a small ferry boat" or more literally as "a small boat for ferrying (people/goods across a river)".
"A small ferry boat" is a concise and commonly used expression that conveys the idea of a small vessel used for transporting passengers or goods across a body of water, which aligns with the function of a "摆渡船" (ferry boat).
If you want to emphasize the action of ferrying, you could say "a small boat used for ferrying", which clarifies the purpose of the boat.
In most contexts, "a small ferry boat" would be sufficient and natural.