Question

a speed boat has stream lined shape . why?

Answer 1

so that it can cut through water as the water pressure can reduce its speed

Answer 2

The boats are designed to what they called as streamline the name itself gives an idea about how it is..
The stream means movement acrros any fluid . line means in a aligned manner ..the boats are designed by inspiration for from fishes.. They are designed to reduce friction which causes and stops the motion so to prevent or to avoid the boats are designed as a streamline.. Just to reduce friction