It could possibly be used for towing larger vessels. That's the only reason I can see for that much power on that kind of boat. I doubt that it is even capable of going very fast.
I've got a 2-man (2-boy?) Dolphin Jr. sailboat from the 1970's at my grandfather's house. I used to take it out on the lake when I went to stay with him for the summer - what a blast this little boat was! I felt like king of the lake in this thing. It's a 15' boat.
This one isn't mine, but it's about what it looked like: